Merge branch 'master' into object-spread

src/compiler/binder.ts

@@ -499,8 +499,8 @@ namespace ts {
                 const saveReturnTarget = currentReturnTarget;
                 const saveActiveLabels = activeLabels;
                 const saveHasExplicitReturn = hasExplicitReturn;
-                const isIIFE = containerFlags & ContainerFlags.IsFunctionExpression && !!getImmediatelyInvokedFunctionExpression(node);
-                // An IIFE is considered part of the containing control flow. Return statements behave
+                const isIIFE = containerFlags & ContainerFlags.IsFunctionExpression && !hasModifier(node, ModifierFlags.Async) && !!getImmediatelyInvokedFunctionExpression(node);
+                // A non-async IIFE is considered part of the containing control flow. Return statements behave
                 // similarly to break statements that exit to a label just past the statement body.
                 if (isIIFE) {
                     currentReturnTarget = createBranchLabel();
@@ -892,8 +892,13 @@ namespace ts {
 
         function bindDoStatement(node: DoStatement): void {
             const preDoLabel = createLoopLabel();
-            const preConditionLabel = createBranchLabel();
-            const postDoLabel = createBranchLabel();
+            const enclosingLabeledStatement = node.parent.kind === SyntaxKind.LabeledStatement
+                ? lastOrUndefined(activeLabels)
+                : undefined;
+            // if do statement is wrapped in labeled statement then target labels for break/continue with or without 
+            // label should be the same 
+            const preConditionLabel = enclosingLabeledStatement ? enclosingLabeledStatement.continueTarget : createBranchLabel();
+            const postDoLabel = enclosingLabeledStatement ? enclosingLabeledStatement.breakTarget : createBranchLabel();
             addAntecedent(preDoLabel, currentFlow);
             currentFlow = preDoLabel;
             bindIterativeStatement(node.statement, postDoLabel, preConditionLabel);
@@ -1111,8 +1116,11 @@ namespace ts {
             if (!activeLabel.referenced && !options.allowUnusedLabels) {
                 file.bindDiagnostics.push(createDiagnosticForNode(node.label, Diagnostics.Unused_label));
             }
-            addAntecedent(postStatementLabel, currentFlow);
-            currentFlow = finishFlowLabel(postStatementLabel);
+            if (!node.statement || node.statement.kind !== SyntaxKind.DoStatement) {
+                // do statement sets current flow inside bindDoStatement
+                addAntecedent(postStatementLabel, currentFlow);
+                currentFlow = finishFlowLabel(postStatementLabel);
+            }
         }
 
         function bindDestructuringTargetFlow(node: Expression) {
@@ -1204,9 +1212,9 @@ namespace ts {
             }
             else {
                 forEachChild(node, bind);
-                if (operator === SyntaxKind.EqualsToken && !isAssignmentTarget(node)) {
+                if (isAssignmentOperator(operator) && !isAssignmentTarget(node)) {
                     bindAssignmentTargetFlow(node.left);
-                    if (node.left.kind === SyntaxKind.ElementAccessExpression) {
+                    if (operator === SyntaxKind.EqualsToken && node.left.kind === SyntaxKind.ElementAccessExpression) {
                         const elementAccess = <ElementAccessExpression>node.left;
                         if (isNarrowableOperand(elementAccess.expression)) {
                             currentFlow = createFlowArrayMutation(currentFlow, node);
@@ -3093,6 +3101,8 @@ namespace ts {
             case SyntaxKind.InterfaceDeclaration:
             case SyntaxKind.TypeAliasDeclaration:
             case SyntaxKind.ThisType:
+            case SyntaxKind.TypeOperator:
+            case SyntaxKind.IndexedAccessType:
             case SyntaxKind.LiteralType:
                 // Types and signatures are TypeScript syntax, and exclude all other facts.
                 transformFlags = TransformFlags.AssertTypeScript;

src/compiler/commandLineParser.ts

@@ -1008,9 +1008,7 @@ namespace ts {
     function convertTypingOptionsFromJsonWorker(jsonOptions: any,
         basePath: string, errors: Diagnostic[], configFileName?: string): TypingOptions {
 
-        const options: TypingOptions = getBaseFileName(configFileName) === "jsconfig.json"
-            ? { enableAutoDiscovery: true, include: [], exclude: [] }
-            : { enableAutoDiscovery: false, include: [], exclude: [] };
+        const options: TypingOptions = { enableAutoDiscovery: getBaseFileName(configFileName) === "jsconfig.json", include: [], exclude: [] };
         convertOptionsFromJson(typingOptionDeclarations, jsonOptions, basePath, options, Diagnostics.Unknown_typing_option_0, errors);
         return options;
     }
@@ -1263,12 +1261,13 @@ namespace ts {
     /**
      * Gets directories in a set of include patterns that should be watched for changes.
      */
-    function getWildcardDirectories(include: string[], exclude: string[], path: string, useCaseSensitiveFileNames: boolean) {
+    function getWildcardDirectories(include: string[], exclude: string[], path: string, useCaseSensitiveFileNames: boolean): Map<WatchDirectoryFlags> {
         // We watch a directory recursively if it contains a wildcard anywhere in a directory segment
         // of the pattern:
         //
         //  /a/b/**/d   - Watch /a/b recursively to catch changes to any d in any subfolder recursively
         //  /a/b/*/d    - Watch /a/b recursively to catch any d in any immediate subfolder, even if a new subfolder is added
+        //  /a/b        - Watch /a/b recursively to catch changes to anything in any recursive subfoler
         //
         // We watch a directory without recursion if it contains a wildcard in the file segment of
         // the pattern:
@@ -1281,15 +1280,14 @@ namespace ts {
         if (include !== undefined) {
             const recursiveKeys: string[] = [];
             for (const file of include) {
-                const name = normalizePath(combinePaths(path, file));
-                if (excludeRegex && excludeRegex.test(name)) {
+                const spec = normalizePath(combinePaths(path, file));
+                if (excludeRegex && excludeRegex.test(spec)) {
                     continue;
                 }
 
-                const match = wildcardDirectoryPattern.exec(name);
+                const match = getWildcardDirectoryFromSpec(spec, useCaseSensitiveFileNames);
                 if (match) {
-                    const key = useCaseSensitiveFileNames ? match[0] : match[0].toLowerCase();
-                    const flags = watchRecursivePattern.test(name) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None;
+                    const { key, flags } = match;
                     const existingFlags = wildcardDirectories[key];
                     if (existingFlags === undefined || existingFlags < flags) {
                         wildcardDirectories[key] = flags;
@@ -1313,6 +1311,20 @@ namespace ts {
         return wildcardDirectories;
     }
 
+    function getWildcardDirectoryFromSpec(spec: string, useCaseSensitiveFileNames: boolean): { key: string, flags: WatchDirectoryFlags } | undefined {
+        const match = wildcardDirectoryPattern.exec(spec);
+        if (match) {
+            return {
+                key: useCaseSensitiveFileNames ? match[0] : match[0].toLowerCase(),
+                flags: watchRecursivePattern.test(spec) ? WatchDirectoryFlags.Recursive : WatchDirectoryFlags.None
+            };
+        }
+        if (isImplicitGlob(spec)) {
+            return { key: spec, flags: WatchDirectoryFlags.Recursive };
+        }
+        return undefined;
+    }
+
     /**
      * Determines whether a literal or wildcard file has already been included that has a higher
      * extension priority.

src/compiler/core.ts

@@ -124,6 +124,13 @@ namespace ts {
         return undefined;
     }
 
+    export function zipWith<T, U>(arrayA: T[], arrayB: U[], callback: (a: T, b: U, index: number) => void): void {
+        Debug.assert(arrayA.length === arrayB.length);
+        for (let i = 0; i < arrayA.length; i++) {
+            callback(arrayA[i], arrayB[i], i);
+        }
+    }
+
     /**
      * Iterates through `array` by index and performs the callback on each element of array until the callback
      * returns a falsey value, then returns false.
@@ -439,8 +446,8 @@ namespace ts {
     }
 
     export function concatenate<T>(array1: T[], array2: T[]): T[] {
-        if (!array2 || !array2.length) return array1;
-        if (!array1 || !array1.length) return array2;
+        if (!some(array2)) return array1;
+        if (!some(array1)) return array2;
         return [...array1, ...array2];
     }
 
@@ -520,6 +527,27 @@ namespace ts {
         return result || array;
     }
 
+    /**
+     * Gets the relative complement of `arrayA` with respect to `b`, returning the elements that
+     * are not present in `arrayA` but are present in `arrayB`. Assumes both arrays are sorted
+     * based on the provided comparer.
+     */
+    export function relativeComplement<T>(arrayA: T[] | undefined, arrayB: T[] | undefined, comparer: (x: T, y: T) => Comparison = compareValues, offsetA = 0, offsetB = 0): T[] | undefined {
+        if (!arrayB || !arrayA || arrayB.length === 0 || arrayA.length === 0) return arrayB;
+        const result: T[] = [];
+        outer: for (; offsetB < arrayB.length; offsetB++) {
+            inner: for (; offsetA < arrayA.length; offsetA++) {
+                switch (comparer(arrayB[offsetB], arrayA[offsetA])) {
+                    case Comparison.LessThan: break inner;
+                    case Comparison.EqualTo: continue outer;
+                    case Comparison.GreaterThan: continue inner;
+                }
+            }
+            result.push(arrayB[offsetB]);
+        }
+        return result;
+    }
+
     export function sum(array: any[], prop: string): number {
         let result = 0;
         for (const v of array) {
@@ -619,12 +647,12 @@ namespace ts {
      * @param array A sorted array whose first element must be no larger than number
      * @param number The value to be searched for in the array.
      */
-    export function binarySearch<T>(array: T[], value: T, comparer?: (v1: T, v2: T) => number): number {
+    export function binarySearch<T>(array: T[], value: T, comparer?: (v1: T, v2: T) => number, offset?: number): number {
         if (!array || array.length === 0) {
             return -1;
         }
 
-        let low = 0;
+        let low = offset || 0;
         let high = array.length - 1;
         comparer = comparer !== undefined
             ? comparer
@@ -1305,7 +1333,7 @@ namespace ts {
      */
     export function getDirectoryPath(path: Path): Path;
     export function getDirectoryPath(path: string): string;
-    export function getDirectoryPath(path: string): any {
+    export function getDirectoryPath(path: string): string {
         return path.substr(0, Math.max(getRootLength(path), path.lastIndexOf(directorySeparator)));
     }
 
@@ -1565,6 +1593,10 @@ namespace ts {
         return expectedPos >= 0 && str.indexOf(suffix, expectedPos) === expectedPos;
     }
 
+    export function hasExtension(fileName: string): boolean {
+        return getBaseFileName(fileName).indexOf(".") >= 0;
+    }
+
     export function fileExtensionIs(path: string, extension: string): boolean {
         return path.length > extension.length && endsWith(path, extension);
     }
@@ -1610,73 +1642,21 @@ namespace ts {
 
         let pattern = "";
         let hasWrittenSubpattern = false;
-        spec: for (const spec of specs) {
+        for (const spec of specs) {
             if (!spec) {
                 continue;
             }
 
-            let subpattern = "";
-            let hasRecursiveDirectoryWildcard = false;
-            let hasWrittenComponent = false;
-            const components = getNormalizedPathComponents(spec, basePath);
-            if (usage !== "exclude" && components[components.length - 1] === "**") {
-                continue spec;
-            }
-
-            // getNormalizedPathComponents includes the separator for the root component.
-            // We need to remove to create our regex correctly.
-            components[0] = removeTrailingDirectorySeparator(components[0]);
-
-            let optionalCount = 0;
-            for (let component of components) {
-                if (component === "**") {
-                    if (hasRecursiveDirectoryWildcard) {
-                        continue spec;
-                    }
-
-                    subpattern += doubleAsteriskRegexFragment;
-                    hasRecursiveDirectoryWildcard = true;
-                    hasWrittenComponent = true;
-                }
-                else {
-                    if (usage === "directories") {
-                        subpattern += "(";
-                        optionalCount++;
-                    }
-
-                    if (hasWrittenComponent) {
-                        subpattern += directorySeparator;
-                    }
-
-                    if (usage !== "exclude") {
-                        // The * and ? wildcards should not match directories or files that start with . if they
-                        // appear first in a component. Dotted directories and files can be included explicitly
-                        // like so: **/.*/.*
-                        if (component.charCodeAt(0) === CharacterCodes.asterisk) {
-                            subpattern += "([^./]" + singleAsteriskRegexFragment + ")?";
-                            component = component.substr(1);
-                        }
-                        else if (component.charCodeAt(0) === CharacterCodes.question) {
-                            subpattern += "[^./]";
-                            component = component.substr(1);
-                        }
-                    }
-
-                    subpattern += component.replace(reservedCharacterPattern, replaceWildcardCharacter);
-                    hasWrittenComponent = true;
-                }
-            }
-
-            while (optionalCount > 0) {
-                subpattern += ")?";
-                optionalCount--;
+            const subPattern = getSubPatternFromSpec(spec, basePath, usage, singleAsteriskRegexFragment, doubleAsteriskRegexFragment, replaceWildcardCharacter);
+            if (subPattern === undefined) {
+                continue;
             }
 
             if (hasWrittenSubpattern) {
                 pattern += "|";
             }
 
-            pattern += "(" + subpattern + ")";
+            pattern += "(" + subPattern + ")";
             hasWrittenSubpattern = true;
         }
 
@@ -1684,7 +1664,83 @@ namespace ts {
             return undefined;
         }
 
-        return "^(" + pattern + (usage === "exclude" ? ")($|/)" : ")$");
+        // If excluding, match "foo/bar/baz...", but if including, only allow "foo".
+        const terminator = usage === "exclude" ? "($|/)" : "$";
+        return `^(${pattern})${terminator}`;
+    }
+
+    /**
+     * An "includes" path "foo" is implicitly a glob "foo/** /*" (without the space) if its last component has no extension,
+     * and does not contain any glob characters itself.
+     */
+    export function isImplicitGlob(lastPathComponent: string): boolean {
+        return !/[.*?]/.test(lastPathComponent);
+    }
+
+    function getSubPatternFromSpec(spec: string, basePath: string, usage: "files" | "directories" | "exclude", singleAsteriskRegexFragment: string, doubleAsteriskRegexFragment: string, replaceWildcardCharacter: (match: string) => string): string | undefined {
+        let subpattern = "";
+        let hasRecursiveDirectoryWildcard = false;
+        let hasWrittenComponent = false;
+        const components = getNormalizedPathComponents(spec, basePath);
+        const lastComponent = lastOrUndefined(components);
+        if (usage !== "exclude" && lastComponent === "**") {
+            return undefined;
+        }
+
+        // getNormalizedPathComponents includes the separator for the root component.
+        // We need to remove to create our regex correctly.
+        components[0] = removeTrailingDirectorySeparator(components[0]);
+
+        if (isImplicitGlob(lastComponent)) {
+            components.push("**", "*");
+        }
+
+        let optionalCount = 0;
+        for (let component of components) {
+            if (component === "**") {
+                if (hasRecursiveDirectoryWildcard) {
+                    return undefined;
+                }
+
+                subpattern += doubleAsteriskRegexFragment;
+                hasRecursiveDirectoryWildcard = true;
+            }
+            else {
+                if (usage === "directories") {
+                    subpattern += "(";
+                    optionalCount++;
+                }
+
+                if (hasWrittenComponent) {
+                    subpattern += directorySeparator;
+                }
+
+                if (usage !== "exclude") {
+                    // The * and ? wildcards should not match directories or files that start with . if they
+                    // appear first in a component. Dotted directories and files can be included explicitly
+                    // like so: **/.*/.*
+                    if (component.charCodeAt(0) === CharacterCodes.asterisk) {
+                        subpattern += "([^./]" + singleAsteriskRegexFragment + ")?";
+                        component = component.substr(1);
+                    }
+                    else if (component.charCodeAt(0) === CharacterCodes.question) {
+                        subpattern += "[^./]";
+                        component = component.substr(1);
+                    }
+                }
+
+                subpattern += component.replace(reservedCharacterPattern, replaceWildcardCharacter);
+            }
+
+            hasWrittenComponent = true;
+        }
+
+        while (optionalCount > 0) {
+            subpattern += ")?";
+            optionalCount--;
+        }
+
+        return subpattern;
     }
 
     function replaceWildCardCharacterFiles(match: string) {
@@ -1771,6 +1827,7 @@ namespace ts {
     function getBasePaths(path: string, includes: string[], useCaseSensitiveFileNames: boolean) {
         // Storage for our results in the form of literal paths (e.g. the paths as written by the user).
         const basePaths: string[] = [path];
+
         if (includes) {
             // Storage for literal base paths amongst the include patterns.
             const includeBasePaths: string[] = [];
@@ -1778,14 +1835,8 @@ namespace ts {
                 // We also need to check the relative paths by converting them to absolute and normalizing
                 // in case they escape the base path (e.g "..\somedirectory")
                 const absolute: string = isRootedDiskPath(include) ? include : normalizePath(combinePaths(path, include));
-
-                const wildcardOffset = indexOfAnyCharCode(absolute, wildcardCharCodes);
-                const includeBasePath = wildcardOffset < 0
-                    ? removeTrailingDirectorySeparator(getDirectoryPath(absolute))
-                    : absolute.substring(0, absolute.lastIndexOf(directorySeparator, wildcardOffset));
-
                 // Append the literal and canonical candidate base paths.
-                includeBasePaths.push(includeBasePath);
+                includeBasePaths.push(getIncludeBasePath(absolute));
             }
 
             // Sort the offsets array using either the literal or canonical path representations.
@@ -1793,21 +1844,27 @@ namespace ts {
 
             // Iterate over each include base path and include unique base paths that are not a
             // subpath of an existing base path
-            include: for (let i = 0; i < includeBasePaths.length; i++) {
-                const includeBasePath = includeBasePaths[i];
-                for (let j = 0; j < basePaths.length; j++) {
-                    if (containsPath(basePaths[j], includeBasePath, path, !useCaseSensitiveFileNames)) {
-                        continue include;
-                    }
+            for (const includeBasePath of includeBasePaths) {
+                if (ts.every(basePaths, basePath => !containsPath(basePath, includeBasePath, path, !useCaseSensitiveFileNames))) {
+                    basePaths.push(includeBasePath);
                 }
-
-                basePaths.push(includeBasePath);
             }
         }
 
         return basePaths;
     }
 
+    function getIncludeBasePath(absolute: string): string {
+        const wildcardOffset = indexOfAnyCharCode(absolute, wildcardCharCodes);
+        if (wildcardOffset < 0) {
+            // No "*" or "?" in the path
+            return !hasExtension(absolute)
+                ? absolute
+                : removeTrailingDirectorySeparator(getDirectoryPath(absolute));
+        }
+        return absolute.substring(0, absolute.lastIndexOf(directorySeparator, wildcardOffset));
+    }
+
     export function ensureScriptKind(fileName: string, scriptKind?: ScriptKind): ScriptKind {
         // Using scriptKind as a condition handles both:
         // - 'scriptKind' is unspecified and thus it is `undefined`

src/compiler/declarationEmitter.ts

@@ -413,6 +413,10 @@ namespace ts {
                     return emitIntersectionType(<IntersectionTypeNode>type);
                 case SyntaxKind.ParenthesizedType:
                     return emitParenType(<ParenthesizedTypeNode>type);
+                case SyntaxKind.TypeOperator:
+                    return emitTypeOperator(<TypeOperatorNode>type);
+                case SyntaxKind.IndexedAccessType:
+                    return emitPropertyAccessType(<IndexedAccessTypeNode>type);
                 case SyntaxKind.FunctionType:
                 case SyntaxKind.ConstructorType:
                     return emitSignatureDeclarationWithJsDocComments(<FunctionOrConstructorTypeNode>type);
@@ -506,6 +510,19 @@ namespace ts {
                 write(")");
             }
 
+            function emitTypeOperator(type: TypeOperatorNode) {
+                write(tokenToString(type.operator));
+                write(" ");
+                emitType(type.type);
+            }
+
+            function emitPropertyAccessType(node: IndexedAccessTypeNode) {
+                emitType(node.objectType);
+                write("[");
+                emitType(node.indexType);
+                write("]");
+            }
+
             function emitTypeLiteral(type: TypeLiteralNode) {
                 write("{");
                 if (type.members.length) {

src/compiler/diagnosticMessages.json

@@ -163,7 +163,7 @@
         "category": "Error",
         "code": 1054
     },
-    "Type '{0}' is not a valid async function return type.": {
+    "Type '{0}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.": {
         "category": "Error",
         "code": 1055
     },
@@ -1071,7 +1071,7 @@
         "category": "Error",
         "code": 2356
     },
-    "The operand of an increment or decrement operator must be a variable, property or indexer.": {
+    "The operand of an increment or decrement operator must be a variable or a property access.": {
         "category": "Error",
         "code": 2357
     },
@@ -1099,7 +1099,7 @@
         "category": "Error",
         "code": 2363
     },
-    "Invalid left-hand side of assignment expression.": {
+    "The left-hand side of an assignment expression must be a variable or a property access.": {
         "category": "Error",
         "code": 2364
     },
@@ -1259,7 +1259,7 @@
         "category": "Error",
         "code": 2405
     },
-    "Invalid left-hand side in 'for...in' statement.": {
+    "The left-hand side of a 'for...in' statement must be a variable or a property access.": {
         "category": "Error",
         "code": 2406
     },
@@ -1411,14 +1411,6 @@
         "category": "Error",
         "code": 2448
     },
-    "The operand of an increment or decrement operator cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2449
-    },
-    "Left-hand side of assignment expression cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2450
-    },
     "Cannot redeclare block-scoped variable '{0}'.": {
         "category": "Error",
         "code": 2451
@@ -1551,15 +1543,7 @@
         "category": "Error",
         "code": 2484
     },
-    "The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2485
-    },
-    "The left-hand side of a 'for...in' statement cannot be a constant or a read-only property.": {
-        "category": "Error",
-        "code": 2486
-    },
-    "Invalid left-hand side in 'for...of' statement.": {
+    "The left-hand side of a 'for...of' statement must be a variable or a property access.": {
         "category": "Error",
         "code": 2487
     },
@@ -1747,6 +1731,34 @@
         "category": "Error",
         "code": 2535
     },
+    "Type '{0}' is not constrained to 'keyof {1}'.": {
+        "category": "Error",
+        "code": 2536
+    },
+    "Type '{0}' has no matching index signature for type '{1}'.": {
+        "category": "Error",
+        "code": 2537
+    },
+    "Type '{0}' cannot be used as an index type.": {
+        "category": "Error",
+        "code": 2538
+    },
+    "Cannot assign to '{0}' because it is not a variable.": {
+        "category": "Error",
+        "code": 2539
+    },
+    "Cannot assign to '{0}' because it is a constant or a read-only property.": {
+        "category": "Error",
+        "code": 2540
+    },
+    "The target of an assignment must be a variable or a property access.": {
+        "category": "Error",
+        "code": 2541
+    },
+    "Index signature in type '{0}' only permits reading.": {
+        "category": "Error",
+        "code": 2542
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
@@ -1839,6 +1851,10 @@
         "category": "Error",
         "code": 2664
     },
+    "Invalid module name in augmentation. Module '{0}' resolves to an untyped module at '{1}', which cannot be augmented.": {
+        "category": "Error",
+        "code": 2665
+    },
     "Exports and export assignments are not permitted in module augmentations.": {
         "category": "Error",
         "code": 2666
@@ -1963,14 +1979,18 @@
         "category": "Error",
         "code": 2696
     },
-    "Interface declaration cannot contain a spread property.": {
+    "An async function or method must return a 'Promise'. Make sure you have a declaration for 'Promise' or include 'ES2015' in your `--lib` option.": {
         "category": "Error",
         "code": 2697
     },
-    "Type literals with spreads cannot contain index, call or construct signatures.": {
+    "Interface declaration cannot contain a spread property.": {
         "category": "Error",
         "code": 2698
     },
+    "Type literals with spreads cannot contain index, call or construct signatures.": {
+        "category": "Error",
+        "code": 2699
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
@@ -2909,7 +2929,11 @@
         "category": "Error",
         "code": 7015
     },
-    "Index signature of object type implicitly has an 'any' type.": {
+    "Could not find a declaration file for module '{0}'. '{1}' implicitly has an 'any' type.": {
+        "category": "Error",
+        "code": 7016
+    },
+    "Element implicitly has an 'any' type because type '{0}' has no index signature.": {
         "category": "Error",
         "code": 7017
     },

src/compiler/emitter.ts

@@ -594,6 +594,10 @@ const _super = (function (geti, seti) {
                     return emitExpressionWithTypeArguments(<ExpressionWithTypeArguments>node);
                 case SyntaxKind.ThisType:
                     return emitThisType();
+                case SyntaxKind.TypeOperator:
+                    return emitTypeOperator(<TypeOperatorNode>node);
+                case SyntaxKind.IndexedAccessType:
+                    return emitPropertyAccessType(<IndexedAccessTypeNode>node);
                 case SyntaxKind.LiteralType:
                     return emitLiteralType(<LiteralTypeNode>node);
 
@@ -1088,6 +1092,19 @@ const _super = (function (geti, seti) {
             write("this");
         }
 
+        function emitTypeOperator(node: TypeOperatorNode) {
+            writeTokenText(node.operator);
+            write(" ");
+            emit(node.type);
+        }
+
+        function emitPropertyAccessType(node: IndexedAccessTypeNode) {
+            emit(node.objectType);
+            write("[");
+            emit(node.indexType);
+            write("]");
+        }
+
         function emitLiteralType(node: LiteralTypeNode) {
             emitExpression(node.literal);
         }

src/compiler/moduleNameResolver.ts

@@ -45,7 +45,7 @@ namespace ts {
     }
 
     /** Adds `isExernalLibraryImport` to a Resolved to get a ResolvedModule. */
-    function resolvedModuleFromResolved({ path, extension }: Resolved, isExternalLibraryImport: boolean): ResolvedModule {
+    function resolvedModuleFromResolved({ path, extension }: Resolved, isExternalLibraryImport: boolean): ResolvedModuleFull {
         return { resolvedFileName: path, extension, isExternalLibraryImport };
     }
 

src/compiler/parser.ts

@@ -138,7 +138,11 @@ namespace ts {
             case SyntaxKind.IntersectionType:
                 return visitNodes(cbNodes, (<UnionOrIntersectionTypeNode>node).types);
             case SyntaxKind.ParenthesizedType:
-                return visitNode(cbNode, (<ParenthesizedTypeNode>node).type);
+            case SyntaxKind.TypeOperator:
+                return visitNode(cbNode, (<ParenthesizedTypeNode | TypeOperatorNode>node).type);
+            case SyntaxKind.IndexedAccessType:
+                return visitNode(cbNode, (<IndexedAccessTypeNode>node).objectType) ||
+                    visitNode(cbNode, (<IndexedAccessTypeNode>node).indexType);
             case SyntaxKind.LiteralType:
                 return visitNode(cbNode, (<LiteralTypeNode>node).literal);
             case SyntaxKind.ObjectBindingPattern:
@@ -2538,14 +2542,39 @@ namespace ts {
         function parseArrayTypeOrHigher(): TypeNode {
             let type = parseNonArrayType();
             while (!scanner.hasPrecedingLineBreak() && parseOptional(SyntaxKind.OpenBracketToken)) {
-                parseExpected(SyntaxKind.CloseBracketToken);
-                const node = <ArrayTypeNode>createNode(SyntaxKind.ArrayType, type.pos);
-                node.elementType = type;
-                type = finishNode(node);
+                if (isStartOfType()) {
+                    const node = <IndexedAccessTypeNode>createNode(SyntaxKind.IndexedAccessType, type.pos);
+                    node.objectType = type;
+                    node.indexType = parseType();
+                    parseExpected(SyntaxKind.CloseBracketToken);
+                    type = finishNode(node);
+                }
+                else {
+                    const node = <ArrayTypeNode>createNode(SyntaxKind.ArrayType, type.pos);
+                    node.elementType = type;
+                    parseExpected(SyntaxKind.CloseBracketToken);
+                    type = finishNode(node);
+                }
             }
             return type;
         }
 
+        function parseTypeOperator(operator: SyntaxKind.KeyOfKeyword) {
+            const node = <TypeOperatorNode>createNode(SyntaxKind.TypeOperator);
+            parseExpected(operator);
+            node.operator = operator;
+            node.type = parseTypeOperatorOrHigher();
+            return finishNode(node);
+        }
+
+        function parseTypeOperatorOrHigher(): TypeNode {
+            switch (token()) {
+                case SyntaxKind.KeyOfKeyword:
+                    return parseTypeOperator(SyntaxKind.KeyOfKeyword);
+            }
+            return parseArrayTypeOrHigher();
+        }
+
         function parseUnionOrIntersectionType(kind: SyntaxKind, parseConstituentType: () => TypeNode, operator: SyntaxKind): TypeNode {
             let type = parseConstituentType();
             if (token() === operator) {
@@ -2562,7 +2591,7 @@ namespace ts {
         }
 
         function parseIntersectionTypeOrHigher(): TypeNode {
-            return parseUnionOrIntersectionType(SyntaxKind.IntersectionType, parseArrayTypeOrHigher, SyntaxKind.AmpersandToken);
+            return parseUnionOrIntersectionType(SyntaxKind.IntersectionType, parseTypeOperatorOrHigher, SyntaxKind.AmpersandToken);
         }
 
         function parseUnionTypeOrHigher(): TypeNode {

src/compiler/program.ts

@@ -329,16 +329,16 @@ namespace ts {
         // Map storing if there is emit blocking diagnostics for given input
         const hasEmitBlockingDiagnostics = createFileMap<boolean>(getCanonicalFileName);
 
-        let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModule[];
+        let resolveModuleNamesWorker: (moduleNames: string[], containingFile: string) => ResolvedModuleFull[];
         if (host.resolveModuleNames) {
             resolveModuleNamesWorker = (moduleNames, containingFile) => host.resolveModuleNames(moduleNames, containingFile).map(resolved => {
                 // An older host may have omitted extension, in which case we should infer it from the file extension of resolvedFileName.
-                if (!resolved || resolved.extension !== undefined) {
-                    return resolved;
+                if (!resolved || (resolved as ResolvedModuleFull).extension !== undefined) {
+                    return resolved as ResolvedModuleFull;
                 }
-                resolved = clone(resolved);
-                resolved.extension = extensionFromPath(resolved.resolvedFileName);
-                return resolved;
+                const withExtension = clone(resolved) as ResolvedModuleFull;
+                withExtension.extension = extensionFromPath(resolved.resolvedFileName);
+                return withExtension;
             });
         }
         else {
@@ -719,6 +719,14 @@ namespace ts {
         }
 
         function getSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
+            // For JavaScript files, we report semantic errors for using TypeScript-only
+            // constructs from within a JavaScript file as syntactic errors.
+            if (isSourceFileJavaScript(sourceFile)) {
+                if (!sourceFile.additionalSyntacticDiagnostics) {
+                    sourceFile.additionalSyntacticDiagnostics = getJavaScriptSyntacticDiagnosticsForFile(sourceFile);
+                }
+                return concatenate(sourceFile.additionalSyntacticDiagnostics, sourceFile.parseDiagnostics);
+            }
             return sourceFile.parseDiagnostics;
         }
 
@@ -751,12 +759,10 @@ namespace ts {
 
                 Debug.assert(!!sourceFile.bindDiagnostics);
                 const bindDiagnostics = sourceFile.bindDiagnostics;
-                // For JavaScript files, we don't want to report the normal typescript semantic errors.
-                // Instead, we just report errors for using TypeScript-only constructs from within a
-                // JavaScript file.
-                const checkDiagnostics = isSourceFileJavaScript(sourceFile) ?
-                    getJavaScriptSemanticDiagnosticsForFile(sourceFile) :
-                    typeChecker.getDiagnostics(sourceFile, cancellationToken);
+                // For JavaScript files, we don't want to report semantic errors.
+                // Instead, we'll report errors for using TypeScript-only constructs from within a
+                // JavaScript file when we get syntactic diagnostics for the file.
+                const checkDiagnostics = isSourceFileJavaScript(sourceFile) ? [] : typeChecker.getDiagnostics(sourceFile, cancellationToken);
                 const fileProcessingDiagnosticsInFile = fileProcessingDiagnostics.getDiagnostics(sourceFile.fileName);
                 const programDiagnosticsInFile = programDiagnostics.getDiagnostics(sourceFile.fileName);
 
@@ -764,7 +770,7 @@ namespace ts {
             });
         }
 
-        function getJavaScriptSemanticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
+        function getJavaScriptSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
             return runWithCancellationToken(() => {
                 const diagnostics: Diagnostic[] = [];
                 walk(sourceFile);
@@ -965,10 +971,6 @@ namespace ts {
             return sortAndDeduplicateDiagnostics(allDiagnostics);
         }
 
-        function hasExtension(fileName: string): boolean {
-            return getBaseFileName(fileName).indexOf(".") >= 0;
-        }
-
         function processRootFile(fileName: string, isDefaultLib: boolean) {
             processSourceFile(normalizePath(fileName), isDefaultLib);
         }
@@ -1294,7 +1296,7 @@ namespace ts {
         function processImportedModules(file: SourceFile) {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
-                file.resolvedModules = createMap<ResolvedModule>();
+                file.resolvedModules = createMap<ResolvedModuleFull>();
                 const moduleNames = map(concatenate(file.imports, file.moduleAugmentations), getTextOfLiteral);
                 const resolutions = resolveModuleNamesWorker(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory));
                 Debug.assert(resolutions.length === moduleNames.length);
@@ -1321,6 +1323,7 @@ namespace ts {
                     // - it's not a top level JavaScript module that exceeded the search max
                     const elideImport = isJsFileFromNodeModules && currentNodeModulesDepth > maxNodeModuleJsDepth;
                     // Don't add the file if it has a bad extension (e.g. 'tsx' if we don't have '--allowJs')
+                    // This may still end up being an untyped module -- the file won't be included but imports will be allowed.
                     const shouldAddFile = resolvedFileName && !getResolutionDiagnostic(options, resolution) && !options.noResolve && i < file.imports.length && !elideImport;
 
                     if (elideImport) {
@@ -1568,22 +1571,29 @@ namespace ts {
 
     /* @internal */
     /**
-     * Returns a DiagnosticMessage if we can't use a resolved module due to its extension.
+     * Returns a DiagnosticMessage if we won't include a resolved module due to its extension.
      * The DiagnosticMessage's parameters are the imported module name, and the filename it resolved to.
+     * This returns a diagnostic even if the module will be an untyped module.
      */
-    export function getResolutionDiagnostic(options: CompilerOptions, { extension }: ResolvedModule): DiagnosticMessage | undefined {
+    export function getResolutionDiagnostic(options: CompilerOptions, { extension }: ResolvedModuleFull): DiagnosticMessage | undefined {
         switch (extension) {
             case Extension.Ts:
             case Extension.Dts:
                 // These are always allowed.
                 return undefined;
-
             case Extension.Tsx:
+                return needJsx();
             case Extension.Jsx:
-                return options.jsx ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
-
+                return needJsx() || needAllowJs();
             case Extension.Js:
-                return options.allowJs ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
+                return needAllowJs();
+        }
+
+        function needJsx() {
+            return options.jsx ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
+        }
+        function needAllowJs() {
+            return options.allowJs ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_allowJs_is_not_set;
         }
     }
 }

src/compiler/scanner.ts

@@ -90,6 +90,7 @@ namespace ts {
         "instanceof": SyntaxKind.InstanceOfKeyword,
         "interface": SyntaxKind.InterfaceKeyword,
         "is": SyntaxKind.IsKeyword,
+        "keyof": SyntaxKind.KeyOfKeyword,
         "let": SyntaxKind.LetKeyword,
         "module": SyntaxKind.ModuleKeyword,
         "namespace": SyntaxKind.NamespaceKeyword,

src/compiler/transformers/es2017.ts

@@ -262,7 +262,8 @@ namespace ts {
         }
 
         function transformAsyncFunctionBody(node: FunctionLikeDeclaration): ConciseBody | FunctionBody {
-            const nodeType = node.original ? (<FunctionLikeDeclaration>node.original).type : node.type;
+            const original = getOriginalNode(node, isFunctionLike);
+            const nodeType = original.type;
             const promiseConstructor = languageVersion < ScriptTarget.ES2015 ? getPromiseConstructor(nodeType) : undefined;
             const isArrowFunction = node.kind === SyntaxKind.ArrowFunction;
             const hasLexicalArguments = (resolver.getNodeCheckFlags(node) & NodeCheckFlags.CaptureArguments) !== 0;
@@ -336,15 +337,16 @@ namespace ts {
         }
 
         function getPromiseConstructor(type: TypeNode) {
-            const typeName = getEntityNameFromTypeNode(type);
-            if (typeName && isEntityName(typeName)) {
-                const serializationKind = resolver.getTypeReferenceSerializationKind(typeName);
-                if (serializationKind === TypeReferenceSerializationKind.TypeWithConstructSignatureAndValue
-                    || serializationKind === TypeReferenceSerializationKind.Unknown) {
-                    return typeName;
+            if (type) {
+                const typeName = getEntityNameFromTypeNode(type);
+                if (typeName && isEntityName(typeName)) {
+                    const serializationKind = resolver.getTypeReferenceSerializationKind(typeName);
+                    if (serializationKind === TypeReferenceSerializationKind.TypeWithConstructSignatureAndValue
+                        || serializationKind === TypeReferenceSerializationKind.Unknown) {
+                        return typeName;
+                    }
                 }
             }
-
             return undefined;
         }
 

src/compiler/transformers/ts.ts

@@ -300,6 +300,8 @@ namespace ts {
                 case SyntaxKind.IntersectionType:
                 case SyntaxKind.ParenthesizedType:
                 case SyntaxKind.ThisType:
+                case SyntaxKind.TypeOperator:
+                case SyntaxKind.IndexedAccessType:
                 case SyntaxKind.LiteralType:
                     // TypeScript type nodes are elided.
 
@@ -1783,6 +1785,8 @@ namespace ts {
                     }
                     // Fallthrough
                 case SyntaxKind.TypeQuery:
+                case SyntaxKind.TypeOperator:
+                case SyntaxKind.IndexedAccessType:
                 case SyntaxKind.TypeLiteral:
                 case SyntaxKind.AnyKeyword:
                 case SyntaxKind.ThisType:

src/compiler/types.ts

@@ -168,6 +168,7 @@ namespace ts {
         DeclareKeyword,
         GetKeyword,
         IsKeyword,
+        KeyOfKeyword,
         ModuleKeyword,
         NamespaceKeyword,
         NeverKeyword,
@@ -216,6 +217,8 @@ namespace ts {
         IntersectionType,
         ParenthesizedType,
         ThisType,
+        TypeOperator,
+        IndexedAccessType,
         LiteralType,
         // Binding patterns
         ObjectBindingPattern,
@@ -426,7 +429,7 @@ namespace ts {
         ThisNodeHasError =   1 << 19, // If the parser encountered an error when parsing the code that created this node
         JavaScriptFile =     1 << 20, // If node was parsed in a JavaScript
         ThisNodeOrAnySubNodesHasError = 1 << 21, // If this node or any of its children had an error
-        HasAggregatedChildData = 1 << 22, // If we've computed data from children and cached it in this node 
+        HasAggregatedChildData = 1 << 22, // If we've computed data from children and cached it in this node
 
         BlockScoped = Let | Const,
 
@@ -895,6 +898,18 @@ namespace ts {
         type: TypeNode;
     }
 
+    export interface TypeOperatorNode extends TypeNode {
+        kind: SyntaxKind.TypeOperator;
+        operator: SyntaxKind.KeyOfKeyword;
+        type: TypeNode;
+    }
+
+    export interface IndexedAccessTypeNode extends TypeNode {
+        kind: SyntaxKind.IndexedAccessType;
+        objectType: TypeNode;
+        indexType: TypeNode;
+    }
+
     export interface LiteralTypeNode extends TypeNode {
         kind: SyntaxKind.LiteralType;
         literal: Expression;
@@ -966,10 +981,6 @@ namespace ts {
         operator: PostfixUnaryOperator;
     }
 
-    export interface PostfixExpression extends UnaryExpression {
-        _postfixExpressionBrand: any;
-    }
-
     export interface LeftHandSideExpression extends IncrementExpression {
         _leftHandSideExpressionBrand: any;
     }
@@ -2087,6 +2098,9 @@ namespace ts {
         // as well as code diagnostics).
         /* @internal */ parseDiagnostics: Diagnostic[];
 
+        // Stores additional file level diagnostics reported by the program
+        /* @internal */ additionalSyntacticDiagnostics?: Diagnostic[];
+
         // File level diagnostics reported by the binder.
         /* @internal */ bindDiagnostics: Diagnostic[];
 
@@ -2097,7 +2111,7 @@ namespace ts {
         // Stores a mapping 'external module reference text' -> 'resolved file name' | undefined
         // It is used to resolve module names in the checker.
         // Content of this field should never be used directly - use getResolvedModuleFileName/setResolvedModuleFileName functions instead
-        /* @internal */ resolvedModules: Map<ResolvedModule>;
+        /* @internal */ resolvedModules: Map<ResolvedModuleFull>;
         /* @internal */ resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
         /* @internal */ imports: LiteralExpression[];
         /* @internal */ moduleAugmentations: LiteralExpression[];
@@ -2687,15 +2701,17 @@ namespace ts {
         Object                  = 1 << 15,  // Object type
         Union                   = 1 << 16,  // Union (T | U)
         Intersection            = 1 << 17,  // Intersection (T & U)
+        Index                   = 1 << 18,  // keyof T
+        IndexedAccess           = 1 << 19,  // T[K]
         /* @internal */
-        FreshLiteral            = 1 << 18,  // Fresh literal type
+        FreshLiteral            = 1 << 20,  // Fresh literal type
         /* @internal */
-        ContainsWideningType    = 1 << 19,  // Type is or contains undefined or null widening type
+        ContainsWideningType    = 1 << 21,  // Type is or contains undefined or null widening type
         /* @internal */
-        ContainsObjectLiteral   = 1 << 20,  // Type is or contains object literal type
+        ContainsObjectLiteral   = 1 << 22,  // Type is or contains object literal type
         /* @internal */
-        ContainsAnyFunctionType = 1 << 21,  // Type is or contains object literal type
-        Spread                  = 1 << 22,  // Spread types
+        ContainsAnyFunctionType = 1 << 23,  // Type is or contains object literal type
+        Spread                  = 1 << 24,  // Spread types
 
         /* @internal */
         Nullable = Undefined | Null,
@@ -2718,7 +2734,7 @@ namespace ts {
 
         // 'Narrowable' types are types where narrowing actually narrows.
         // This *should* be every type other than null, undefined, void, and never
-        Narrowable = Any | StructuredType | TypeParameter | StringLike | NumberLike | BooleanLike | ESSymbol | Spread,
+        Narrowable = Any | StructuredType | TypeParameter | Index | IndexedAccess | StringLike | NumberLike | BooleanLike | ESSymbol | Spread,
         NotUnionOrUnit = Any | ESSymbol | Object,
         /* @internal */
         RequiresWidening = ContainsWideningType | ContainsObjectLiteral,
@@ -2887,9 +2903,22 @@ namespace ts {
         /* @internal */
         resolvedApparentType: Type;
         /* @internal */
+        resolvedIndexType: IndexType;
+        /* @internal */
+        resolvedIndexedAccessTypes: IndexedAccessType[];
+        /* @internal */
         isThisType?: boolean;
     }
 
+    export interface IndexType extends Type {
+        type: TypeParameter;
+    }
+
+    export interface IndexedAccessType extends Type {
+        objectType: Type;
+        indexType: TypeParameter;
+    }
+
     export const enum SignatureKind {
         Call,
         Construct,
@@ -3172,6 +3201,7 @@ namespace ts {
         Pretty,
     }
 
+    /** Either a parsed command line or a parsed tsconfig.json */
     export interface ParsedCommandLine {
         options: CompilerOptions;
         typingOptions?: TypingOptions;
@@ -3382,14 +3412,11 @@ namespace ts {
      * Module resolution will pick up tsx/jsx/js files even if '--jsx' and '--allowJs' are turned off.
      * The Program will then filter results based on these flags.
      *
-     * At least one of `resolvedTsFileName` or `resolvedJsFileName` must be defined,
-     * else resolution should just return `undefined` instead of a ResolvedModule.
+     * Prefer to return a `ResolvedModuleFull` so that the file type does not have to be inferred.
      */
     export interface ResolvedModule {
         /** Path of the file the module was resolved to. */
         resolvedFileName: string;
-        /** Extension of resolvedFileName. This must match what's at the end of resolvedFileName. */
-        extension: Extension;
         /**
          * Denotes if 'resolvedFileName' is isExternalLibraryImport and thus should be a proper external module:
          * - be a .d.ts file
@@ -3399,6 +3426,18 @@ namespace ts {
         isExternalLibraryImport?: boolean;
     }
 
+    /**
+     * ResolvedModule with an explicitly provided `extension` property.
+     * Prefer this over `ResolvedModule`.
+     */
+    export interface ResolvedModuleFull extends ResolvedModule {
+        /**
+         * Extension of resolvedFileName. This must match what's at the end of resolvedFileName.
+         * This is optional for backwards-compatibility, but will be added if not provided.
+         */
+        extension: Extension;
+    }
+
     export enum Extension {
         Ts,
         Tsx,
@@ -3409,7 +3448,7 @@ namespace ts {
     }
 
     export interface ResolvedModuleWithFailedLookupLocations {
-        resolvedModule: ResolvedModule | undefined;
+        resolvedModule: ResolvedModuleFull | undefined;
         failedLookupLocations: string[];
     }
 

src/compiler/utilities.ts

@@ -87,13 +87,13 @@ namespace ts {
         return !!(sourceFile && sourceFile.resolvedModules && sourceFile.resolvedModules[moduleNameText]);
     }
 
-    export function getResolvedModule(sourceFile: SourceFile, moduleNameText: string): ResolvedModule {
+    export function getResolvedModule(sourceFile: SourceFile, moduleNameText: string): ResolvedModuleFull {
         return hasResolvedModule(sourceFile, moduleNameText) ? sourceFile.resolvedModules[moduleNameText] : undefined;
     }
 
-    export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModule): void {
+    export function setResolvedModule(sourceFile: SourceFile, moduleNameText: string, resolvedModule: ResolvedModuleFull): void {
         if (!sourceFile.resolvedModules) {
-            sourceFile.resolvedModules = createMap<ResolvedModule>();
+            sourceFile.resolvedModules = createMap<ResolvedModuleFull>();
         }
 
         sourceFile.resolvedModules[moduleNameText] = resolvedModule;
@@ -108,11 +108,7 @@ namespace ts {
     }
 
     /* @internal */
-    /**
-     * Considers two ResolvedModules equal if they have the same `resolvedFileName`.
-     * Thus `{ ts: foo, js: bar }` is equal to `{ ts: foo, js: baz }` because `ts` is preferred.
-     */
-    export function moduleResolutionIsEqualTo(oldResolution: ResolvedModule, newResolution: ResolvedModule): boolean {
+    export function moduleResolutionIsEqualTo(oldResolution: ResolvedModuleFull, newResolution: ResolvedModuleFull): boolean {
         return oldResolution.isExternalLibraryImport === newResolution.isExternalLibraryImport &&
             oldResolution.extension === newResolution.extension &&
             oldResolution.resolvedFileName === newResolution.resolvedFileName;
@@ -406,6 +402,7 @@ namespace ts {
             ((<ModuleDeclaration>node).name.kind === SyntaxKind.StringLiteral || isGlobalScopeAugmentation(<ModuleDeclaration>node));
     }
 
+    /** Given a symbol for a module, checks that it is either an untyped import or a shorthand ambient module. */
     export function isShorthandAmbientModuleSymbol(moduleSymbol: Symbol): boolean {
         return isShorthandAmbientModule(moduleSymbol.valueDeclaration);
     }
@@ -488,6 +485,17 @@ namespace ts {
         return getFullWidth(name) === 0 ? "(Missing)" : getTextOfNode(name);
     }
 
+    export function entityNameToString(name: EntityNameOrEntityNameExpression): string {
+        switch (name.kind) {
+            case SyntaxKind.Identifier:
+                return getFullWidth(name) === 0 ? unescapeIdentifier((<Identifier>name).text) : getTextOfNode(name);
+            case SyntaxKind.QualifiedName:
+                return entityNameToString((<QualifiedName>name).left) + "." + entityNameToString((<QualifiedName>name).right);
+            case SyntaxKind.PropertyAccessExpression:
+                return entityNameToString((<PropertyAccessEntityNameExpression>name).expression) + "." + entityNameToString((<PropertyAccessEntityNameExpression>name).name);
+        }
+    }
+
     export function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
         const sourceFile = getSourceFileOfNode(node);
         const span = getErrorSpanForNode(sourceFile, node);
@@ -1045,17 +1053,19 @@ namespace ts {
     }
 
     export function getEntityNameFromTypeNode(node: TypeNode): EntityNameOrEntityNameExpression {
-        if (node) {
-            switch (node.kind) {
-                case SyntaxKind.TypeReference:
-                    return (<TypeReferenceNode>node).typeName;
-                case SyntaxKind.ExpressionWithTypeArguments:
-                    Debug.assert(isEntityNameExpression((<ExpressionWithTypeArguments>node).expression));
-                    return <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression;
-                case SyntaxKind.Identifier:
-                case SyntaxKind.QualifiedName:
-                    return (<EntityName><Node>node);
-            }
+        switch (node.kind) {
+            case SyntaxKind.TypeReference:
+            case SyntaxKind.JSDocTypeReference:
+                return (<TypeReferenceNode>node).typeName;
+
+            case SyntaxKind.ExpressionWithTypeArguments:
+                return isEntityNameExpression((<ExpressionWithTypeArguments>node).expression)
+                    ? <EntityNameExpression>(<ExpressionWithTypeArguments>node).expression
+                    : undefined;
+
+            case SyntaxKind.Identifier:
+            case SyntaxKind.QualifiedName:
+                return (<EntityName><Node>node);
         }
 
         return undefined;
@@ -1609,29 +1619,51 @@ namespace ts {
         return node && node.dotDotDotToken !== undefined;
     }
 
+    export const enum AssignmentKind {
+        None, Definite, Compound
+    }
+
+    export function getAssignmentTargetKind(node: Node): AssignmentKind {
+        let parent = node.parent;
+        while (true) {
+            switch (parent.kind) {
+                case SyntaxKind.BinaryExpression:
+                    const binaryOperator = (<BinaryExpression>parent).operatorToken.kind;
+                    return isAssignmentOperator(binaryOperator) && (<BinaryExpression>parent).left === node ?
+                        binaryOperator === SyntaxKind.EqualsToken ? AssignmentKind.Definite : AssignmentKind.Compound :
+                        AssignmentKind.None;
+                case SyntaxKind.PrefixUnaryExpression:
+                case SyntaxKind.PostfixUnaryExpression:
+                    const unaryOperator = (<PrefixUnaryExpression | PostfixUnaryExpression>parent).operator;
+                    return unaryOperator === SyntaxKind.PlusPlusToken || unaryOperator === SyntaxKind.MinusMinusToken ? AssignmentKind.Compound : AssignmentKind.None;
+                case SyntaxKind.ForInStatement:
+                case SyntaxKind.ForOfStatement:
+                    return (<ForInStatement | ForOfStatement>parent).initializer === node ? AssignmentKind.Definite : AssignmentKind.None;
+                case SyntaxKind.ParenthesizedExpression:
+                case SyntaxKind.ArrayLiteralExpression:
+                case SyntaxKind.SpreadExpression:
+                    node = parent;
+                    break;
+                case SyntaxKind.ShorthandPropertyAssignment:
+                    if ((<ShorthandPropertyAssignment>parent).name !== node) {
+                        return AssignmentKind.None;
+                    }
+                    // Fall through
+                case SyntaxKind.PropertyAssignment:
+                    node = parent.parent;
+                    break;
+                default:
+                    return AssignmentKind.None;
+            }
+            parent = node.parent;
+        }
+    }
+
     // A node is an assignment target if it is on the left hand side of an '=' token, if it is parented by a property
     // assignment in an object literal that is an assignment target, or if it is parented by an array literal that is
     // an assignment target. Examples include 'a = xxx', '{ p: a } = xxx', '[{ p: a}] = xxx'.
     export function isAssignmentTarget(node: Node): boolean {
-        while (node.parent.kind === SyntaxKind.ParenthesizedExpression) {
-            node = node.parent;
-        }
-        while (true) {
-            const parent = node.parent;
-            if (parent.kind === SyntaxKind.ArrayLiteralExpression || parent.kind === SyntaxKind.SpreadExpression) {
-                node = parent;
-                continue;
-            }
-            if (parent.kind === SyntaxKind.PropertyAssignment || parent.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                node = parent.parent;
-                continue;
-            }
-            return parent.kind === SyntaxKind.BinaryExpression &&
-                isAssignmentOperator((<BinaryExpression>parent).operatorToken.kind) &&
-                (<BinaryExpression>parent).left === node ||
-                (parent.kind === SyntaxKind.ForInStatement || parent.kind === SyntaxKind.ForOfStatement) &&
-                (<ForInStatement | ForOfStatement>parent).initializer === node;
-        }
+        return getAssignmentTargetKind(node) !== AssignmentKind.None;
     }
 
     export function isNodeDescendantOf(node: Node, ancestor: Node): boolean {

src/harness/fourslash.ts

@@ -438,9 +438,8 @@ namespace FourSlash {
         private getAllDiagnostics(): ts.Diagnostic[] {
             const diagnostics: ts.Diagnostic[] = [];
 
-            const fileNames = this.languageServiceAdapterHost.getFilenames();
-            for (let i = 0, n = fileNames.length; i < n; i++) {
-                diagnostics.push.apply(this.getDiagnostics(fileNames[i]));
+            for (const fileName of this.languageServiceAdapterHost.getFilenames()) {
+                diagnostics.push.apply(this.getDiagnostics(fileName));
             }
 
             return diagnostics;
@@ -580,12 +579,12 @@ namespace FourSlash {
                 this.raiseError(`goToDefinitions failed - expected to find ${endMarkers.length} definitions but got ${definitions.length}`);
             }
 
-            for (let i = 0; i < endMarkers.length; i++) {
-                const marker = this.getMarkerByName(endMarkers[i]), definition = definitions[i];
+            ts.zipWith(endMarkers, definitions, (endMarker, definition, i) => {
+                const marker = this.getMarkerByName(endMarker);
                 if (marker.fileName !== definition.fileName || marker.position !== definition.textSpan.start) {
                     this.raiseError(`goToDefinition failed for definition ${i}: expected ${marker.fileName} at ${marker.position}, got ${definition.fileName} at ${definition.textSpan.start}`);
                 }
-            }
+            });
         }
 
         public verifyGetEmitOutputForCurrentFile(expected: string): void {
@@ -602,10 +601,10 @@ namespace FourSlash {
         public verifyGetEmitOutputContentsForCurrentFile(expected: ts.OutputFile[]): void {
             const emit = this.languageService.getEmitOutput(this.activeFile.fileName);
             assert.equal(emit.outputFiles.length, expected.length, "Number of emit output files");
-            for (let i = 0; i < emit.outputFiles.length; i++) {
-                assert.equal(emit.outputFiles[i].name, expected[i].name, "FileName");
-                assert.equal(emit.outputFiles[i].text, expected[i].text, "Content");
-            }
+            ts.zipWith(emit.outputFiles, expected, (outputFile, expected) => {
+                assert.equal(outputFile.name, expected.name, "FileName");
+                assert.equal(outputFile.text, expected.text, "Content");
+            });
         }
 
         public verifyMemberListContains(symbol: string, text?: string, documentation?: string, kind?: string) {
@@ -668,9 +667,9 @@ namespace FourSlash {
 
             const entries = this.getCompletionListAtCaret().entries;
             assert.isTrue(items.length <= entries.length, `Amount of expected items in completion list [ ${items.length} ] is greater than actual number of items in list [ ${entries.length} ]`);
-            for (let i = 0; i < items.length; i++) {
-                assert.equal(entries[i].name, items[i], `Unexpected item in completion list`);
-            }
+            ts.zipWith(entries, items, (entry, item) => {
+                assert.equal(entry.name, item, `Unexpected item in completion list`);
+            });
         }
 
         public noItemsWithSameNameButDifferentKind(): void {
@@ -692,15 +691,7 @@ namespace FourSlash {
                 this.raiseError("Member list is empty at Caret");
             }
             else if ((members && members.entries.length !== 0) && !negative) {
-
-                let errorMsg = "\n" + "Member List contains: [" + members.entries[0].name;
-                for (let i = 1; i < members.entries.length; i++) {
-                    errorMsg += ", " + members.entries[i].name;
-                }
-                errorMsg += "]\n";
-
-                this.raiseError("Member list is not empty at Caret: " + errorMsg);
-
+                this.raiseError(`Member list is not empty at Caret:\nMember List contains: ${stringify(members.entries.map(e => e.name))}`);
             }
         }
 
@@ -710,13 +701,8 @@ namespace FourSlash {
                 this.raiseError("Completion list is empty at caret at position " + this.activeFile.fileName + " " + this.currentCaretPosition);
             }
             else if (completions && completions.entries.length !== 0 && !negative) {
-                let errorMsg = "\n" + "Completion List contains: [" + completions.entries[0].name;
-                for (let i = 1; i < completions.entries.length; i++) {
-                    errorMsg += ", " + completions.entries[i].name;
-                }
-                errorMsg += "]\n";
-
-                this.raiseError("Completion list is not empty at caret at position " + this.activeFile.fileName + " " + this.currentCaretPosition + errorMsg);
+                this.raiseError(`Completion list is not empty at caret at position ${this.activeFile.fileName} ${this.currentCaretPosition}\n` +
+                    `Completion List contains: ${stringify(completions.entries.map(e => e.name))}`);
             }
         }
 
@@ -890,8 +876,7 @@ namespace FourSlash {
         }
 
         private verifyReferencesWorker(references: ts.ReferenceEntry[], fileName: string, start: number, end: number, isWriteAccess?: boolean, isDefinition?: boolean) {
-            for (let i = 0; i < references.length; i++) {
-                const reference = references[i];
+            for (const reference of references) {
                 if (reference && reference.fileName === fileName && reference.textSpan.start === start && ts.textSpanEnd(reference.textSpan) === end) {
                     if (typeof isWriteAccess !== "undefined" && reference.isWriteAccess !== isWriteAccess) {
                         this.raiseError(`verifyReferencesAtPositionListContains failed - item isWriteAccess value does not match, actual: ${reference.isWriteAccess}, expected: ${isWriteAccess}.`);
@@ -1008,16 +993,11 @@ namespace FourSlash {
                 ranges = ranges.sort((r1, r2) => r1.start - r2.start);
                 references = references.sort((r1, r2) => r1.textSpan.start - r2.textSpan.start);
 
-                for (let i = 0, n = ranges.length; i < n; i++) {
-                    const reference = references[i];
-                    const range = ranges[i];
-
-                    if (reference.textSpan.start !== range.start ||
-                        ts.textSpanEnd(reference.textSpan) !== range.end) {
-
+                ts.zipWith(references, ranges, (reference, range) => {
+                    if (reference.textSpan.start !== range.start || ts.textSpanEnd(reference.textSpan) !== range.end) {
                         this.raiseError("Rename location results do not match.\n\nExpected: " + stringify(ranges) + "\n\nActual:" + JSON.stringify(references));
                     }
-                }
+                });
             }
             else {
                 this.raiseError("Expected rename to succeed, but it actually failed.");
@@ -1247,8 +1227,7 @@ namespace FourSlash {
             const emitFiles: FourSlashFile[] = [];  // List of FourSlashFile that has emitThisFile flag on
 
             const allFourSlashFiles = this.testData.files;
-            for (let idx = 0; idx < allFourSlashFiles.length; idx++) {
-                const file = allFourSlashFiles[idx];
+            for (const file of allFourSlashFiles) {
                 if (file.fileOptions[metadataOptionNames.emitThisFile] === "true") {
                     // Find a file with the flag emitThisFile turned on
                     emitFiles.push(file);
@@ -1273,8 +1252,8 @@ namespace FourSlash {
                         if (emitOutput.emitSkipped) {
                             resultString += "Diagnostics:" + Harness.IO.newLine();
                             const diagnostics = ts.getPreEmitDiagnostics(this.languageService.getProgram());
-                            for (let i = 0, n = diagnostics.length; i < n; i++) {
-                                resultString += "  " + diagnostics[0].messageText + Harness.IO.newLine();
+                            for (const diagnostic of diagnostics) {
+                                resultString += "  " + diagnostic.messageText + Harness.IO.newLine();
                             }
                         }
 
@@ -1340,8 +1319,7 @@ namespace FourSlash {
         }
 
         public printCurrentFileState(makeWhitespaceVisible = false, makeCaretVisible = true) {
-            for (let i = 0; i < this.testData.files.length; i++) {
-                const file = this.testData.files[i];
+            for (const file of this.testData.files) {
                 const active = (this.activeFile === file);
                 Harness.IO.log(`=== Script (${file.fileName}) ${(active ? "(active, cursor at |)" : "")} ===`);
                 let content = this.getFileContent(file.fileName);
@@ -1576,10 +1554,10 @@ namespace FourSlash {
             edits = edits.sort((a, b) => a.span.start - b.span.start);
             // Get a snapshot of the content of the file so we can make sure any formatting edits didn't destroy non-whitespace characters
             const oldContent = this.getFileContent(this.activeFile.fileName);
-            for (let j = 0; j < edits.length; j++) {
-                this.languageServiceAdapterHost.editScript(fileName, edits[j].span.start + runningOffset, ts.textSpanEnd(edits[j].span) + runningOffset, edits[j].newText);
-                this.updateMarkersForEdit(fileName, edits[j].span.start + runningOffset, ts.textSpanEnd(edits[j].span) + runningOffset, edits[j].newText);
-                const change = (edits[j].span.start - ts.textSpanEnd(edits[j].span)) + edits[j].newText.length;
+            for (const edit of edits) {
+                this.languageServiceAdapterHost.editScript(fileName, edit.span.start + runningOffset, ts.textSpanEnd(edit.span) + runningOffset, edit.newText);
+                this.updateMarkersForEdit(fileName, edit.span.start + runningOffset, ts.textSpanEnd(edit.span) + runningOffset, edit.newText);
+                const change = (edit.span.start - ts.textSpanEnd(edit.span)) + edit.newText.length;
                 runningOffset += change;
                 // TODO: Consider doing this at least some of the time for higher fidelity. Currently causes a failure (bug 707150)
                 // this.languageService.getScriptLexicalStructure(fileName);
@@ -1913,10 +1891,7 @@ namespace FourSlash {
                     jsonMismatchString());
             }
 
-            for (let i = 0; i < expected.length; i++) {
-                const expectedClassification = expected[i];
-                const actualClassification = actual[i];
-
+            ts.zipWith(expected, actual, (expectedClassification, actualClassification) => {
                 const expectedType: string = (<any>ts.ClassificationTypeNames)[expectedClassification.classificationType];
                 if (expectedType !== actualClassification.classificationType) {
                     this.raiseError("verifyClassifications failed - expected classifications type to be " +
@@ -1946,7 +1921,7 @@ namespace FourSlash {
                         actualText +
                         jsonMismatchString());
                 }
-            }
+            });
 
             function jsonMismatchString() {
                 return Harness.IO.newLine() +
@@ -1991,13 +1966,11 @@ namespace FourSlash {
                 this.raiseError(`verifyOutliningSpans failed - expected total spans to be ${spans.length}, but was ${actual.length}`);
             }
 
-            for (let i = 0; i < spans.length; i++) {
-                const expectedSpan = spans[i];
-                const actualSpan = actual[i];
+            ts.zipWith(spans, actual, (expectedSpan, actualSpan, i) => {
                 if (expectedSpan.start !== actualSpan.textSpan.start || expectedSpan.end !== ts.textSpanEnd(actualSpan.textSpan)) {
                     this.raiseError(`verifyOutliningSpans failed - span ${(i + 1)} expected: (${expectedSpan.start},${expectedSpan.end}),  actual: (${actualSpan.textSpan.start},${ts.textSpanEnd(actualSpan.textSpan)})`);
                 }
-            }
+            });
         }
 
         public verifyTodoComments(descriptors: string[], spans: TextSpan[]) {
@@ -2008,15 +1981,13 @@ namespace FourSlash {
                 this.raiseError(`verifyTodoComments failed - expected total spans to be ${spans.length}, but was ${actual.length}`);
             }
 
-            for (let i = 0; i < spans.length; i++) {
-                const expectedSpan = spans[i];
-                const actualComment = actual[i];
+            ts.zipWith(spans, actual, (expectedSpan, actualComment, i) => {
                 const actualCommentSpan = ts.createTextSpan(actualComment.position, actualComment.message.length);
 
                 if (expectedSpan.start !== actualCommentSpan.start || expectedSpan.end !== ts.textSpanEnd(actualCommentSpan)) {
                     this.raiseError(`verifyOutliningSpans failed - span ${(i + 1)} expected: (${expectedSpan.start},${expectedSpan.end}),  actual: (${actualCommentSpan.start},${ts.textSpanEnd(actualCommentSpan)})`);
                 }
-            }
+            });
         }
 
         private getCodeFixes(errorCode?: number) {
@@ -2163,11 +2134,9 @@ namespace FourSlash {
         public verifyNavigationItemsCount(expected: number, searchValue: string, matchKind?: string, fileName?: string) {
             const items = this.languageService.getNavigateToItems(searchValue, /*maxResultCount*/ undefined, fileName);
             let actual = 0;
-            let item: ts.NavigateToItem;
 
             // Count only the match that match the same MatchKind
-            for (let i = 0; i < items.length; i++) {
-                item = items[i];
+            for (const item of items) {
                 if (!matchKind || item.matchKind === matchKind) {
                     actual++;
                 }
@@ -2195,8 +2164,7 @@ namespace FourSlash {
                 this.raiseError("verifyNavigationItemsListContains failed - found 0 navigation items, expected at least one.");
             }
 
-            for (let i = 0; i < items.length; i++) {
-                const item = items[i];
+            for (const item of items) {
                 if (item && item.name === name && item.kind === kind &&
                     (matchKind === undefined || item.matchKind === matchKind) &&
                     (fileName === undefined || item.fileName === fileName) &&
@@ -2247,24 +2215,16 @@ namespace FourSlash {
 
         public printNavigationItems(searchValue: string) {
             const items = this.languageService.getNavigateToItems(searchValue);
-            const length = items && items.length;
-
-            Harness.IO.log(`NavigationItems list (${length} items)`);
-
-            for (let i = 0; i < length; i++) {
-                const item = items[i];
+            Harness.IO.log(`NavigationItems list (${items.length} items)`);
+            for (const item of items) {
                 Harness.IO.log(`name: ${item.name}, kind: ${item.kind}, parentName: ${item.containerName}, fileName: ${item.fileName}`);
             }
         }
 
         public printNavigationBar() {
             const items = this.languageService.getNavigationBarItems(this.activeFile.fileName);
-            const length = items && items.length;
-
-            Harness.IO.log(`Navigation bar (${length} items)`);
-
-            for (let i = 0; i < length; i++) {
-                const item = items[i];
+            Harness.IO.log(`Navigation bar (${items.length} items)`);
+            for (const item of items) {
                 Harness.IO.log(`${repeatString(item.indent, " ")}name: ${item.text}, kind: ${item.kind}, childItems: ${item.childItems.map(child => child.text)}`);
             }
         }
@@ -2385,8 +2345,7 @@ namespace FourSlash {
         }
 
         private assertItemInCompletionList(items: ts.CompletionEntry[], name: string, text?: string, documentation?: string, kind?: string, spanIndex?: number) {
-            for (let i = 0; i < items.length; i++) {
-                const item = items[i];
+            for (const item of items) {
                 if (item.name === name) {
                     if (documentation != undefined || text !== undefined) {
                         const details = this.getCompletionEntryDetails(item.name);
@@ -2435,20 +2394,17 @@ namespace FourSlash {
                 name = name.indexOf("/") === -1 ? (this.basePath + "/" + name) : name;
 
                 const availableNames: string[] = [];
-                let foundIt = false;
-                for (let i = 0; i < this.testData.files.length; i++) {
-                    const fn = this.testData.files[i].fileName;
+                result = ts.forEach(this.testData.files, file => {
+                    const fn = file.fileName;
                     if (fn) {
                         if (fn === name) {
-                            result = this.testData.files[i];
-                            foundIt = true;
-                            break;
+                            return file;
                         }
                         availableNames.push(fn);
                     }
-                }
+                });
 
-                if (!foundIt) {
+                if (!result) {
                     throw new Error(`No test file named "${name}" exists. Available file names are: ${availableNames.join(", ")}`);
                 }
             }
@@ -2549,8 +2505,8 @@ ${code}
 
     function chompLeadingSpace(content: string) {
         const lines = content.split("\n");
-        for (let i = 0; i < lines.length; i++) {
-            if ((lines[i].length !== 0) && (lines[i].charAt(0) !== " ")) {
+        for (const line of lines) {
+            if ((line.length !== 0) && (line.charAt(0) !== " ")) {
                 return content;
             }
         }
@@ -2588,8 +2544,7 @@ ${code}
             currentFileName = fileName;
         }
 
-        for (let i = 0; i < lines.length; i++) {
-            let line = lines[i];
+        for (let line of lines) {
             const lineLength = line.length;
 
             if (lineLength > 0 && line.charAt(lineLength - 1) === "\r") {

src/harness/harness.ts

@@ -1029,7 +1029,7 @@ namespace Harness {
                 },
                 realpath: realPathMap && ((f: string) => {
                     const path = ts.toPath(f, currentDirectory, getCanonicalFileName);
-                    return realPathMap.contains(path) ? realPathMap.get(path) : path;
+                    return realPathMap.get(path) || path;
                 }),
                 directoryExists: dir => {
                     let path = ts.toPath(dir, currentDirectory, getCanonicalFileName);
@@ -1037,13 +1037,7 @@ namespace Harness {
                     if (path[path.length - 1] === "/") {
                         path = <ts.Path>path.substr(0, path.length - 1);
                     }
-                    let exists = false;
-                    fileMap.forEachValue(key => {
-                        if (key.indexOf(path) === 0 && key[path.length] === "/") {
-                            exists = true;
-                        }
-                    });
-                    return exists;
+                    return mapHasFileInDirectory(path, fileMap) || mapHasFileInDirectory(path, realPathMap);
                 },
                 getDirectories: d => {
                     const path = ts.toPath(d, currentDirectory, getCanonicalFileName);
@@ -1064,6 +1058,19 @@ namespace Harness {
             };
         }
 
+        function mapHasFileInDirectory(directoryPath: ts.Path, map: ts.FileMap<any>): boolean {
+            if (!map) {
+                return false;
+            }
+            let exists = false;
+            map.forEachValue(fileName => {
+                if (!exists && ts.startsWith(fileName, directoryPath) && fileName[directoryPath.length] === "/") {
+                    exists = true;
+                }
+            });
+            return exists;
+        }
+
         interface HarnessOptions {
             useCaseSensitiveFileNames?: boolean;
             includeBuiltFile?: string;
@@ -1108,22 +1115,7 @@ namespace Harness {
                     const option = getCommandLineOption(name);
                     if (option) {
                         const errors: ts.Diagnostic[] = [];
-                        switch (option.type) {
-                            case "boolean":
-                                options[option.name] = value.toLowerCase() === "true";
-                                break;
-                            case "string":
-                                options[option.name] = value;
-                                break;
-                            // If not a primitive, the possible types are specified in what is effectively a map of options.
-                            case "list":
-                                options[option.name] = ts.parseListTypeOption(<ts.CommandLineOptionOfListType>option, value, errors);
-                                break;
-                            default:
-                                options[option.name] = ts.parseCustomTypeOption(<ts.CommandLineOptionOfCustomType>option, value, errors);
-                                break;
-                        }
-
+                        options[option.name] = optionValue(option, value, errors);
                         if (errors.length > 0) {
                             throw new Error(`Unknown value '${value}' for compiler option '${name}'.`);
                         }
@@ -1135,6 +1127,27 @@ namespace Harness {
             }
         }
 
+        function optionValue(option: ts.CommandLineOption, value: string, errors: ts.Diagnostic[]): any {
+            switch (option.type) {
+                case "boolean":
+                    return value.toLowerCase() === "true";
+                case "string":
+                    return value;
+                case "number": {
+                    const number = parseInt(value, 10);
+                    if (isNaN(number)) {
+                        throw new Error(`Value must be a number, got: ${JSON.stringify(value)}`);
+                    }
+                    return number;
+                }
+                // If not a primitive, the possible types are specified in what is effectively a map of options.
+                case "list":
+                    return ts.parseListTypeOption(<ts.CommandLineOptionOfListType>option, value, errors);
+                default:
+                    return ts.parseCustomTypeOption(<ts.CommandLineOptionOfCustomType>option, value, errors);
+            }
+        }
+
         export interface TestFile {
             unitName: string;
             content: string;

src/harness/unittests/cachingInServerLSHost.ts

@@ -22,33 +22,17 @@ namespace ts {
             newLine: "\r\n",
             useCaseSensitiveFileNames: false,
             write: noop,
-            readFile: (path: string): string => {
-                return path in fileMap ? fileMap[path].content : undefined;
-            },
-            writeFile: (_path: string, _data: string, _writeByteOrderMark?: boolean) => {
-                return ts.notImplemented();
-            },
-            resolvePath: (_path: string): string => {
-                return ts.notImplemented();
-            },
-            fileExists: (path: string): boolean => {
-                return path in fileMap;
-            },
-            directoryExists: (path: string): boolean => {
-                return existingDirectories[path] || false;
-            },
+            readFile: path => path in fileMap ? fileMap[path].content : undefined,
+            writeFile: notImplemented,
+            resolvePath: notImplemented,
+            fileExists: path => path in fileMap,
+            directoryExists: path => existingDirectories[path] || false,
             createDirectory: noop,
-            getExecutingFilePath: (): string => {
-                return "";
-            },
-            getCurrentDirectory: (): string => {
-                return "";
-            },
+            getExecutingFilePath: () => "",
+            getCurrentDirectory: () => "",
             getDirectories: () => [],
             getEnvironmentVariable: () => "",
-            readDirectory: (_path: string, _extension?: string[], _exclude?: string[], _include?: string[]): string[] => {
-                return ts.notImplemented();
-            },
+            readDirectory: notImplemented,
             exit: noop,
             watchFile: () => ({
                 close: noop
@@ -58,8 +42,8 @@ namespace ts {
             }),
             setTimeout,
             clearTimeout,
-            setImmediate,
-            clearImmediate
+            setImmediate: typeof setImmediate !== "undefined" ? setImmediate : action => setTimeout(action, 0),
+            clearImmediate: typeof clearImmediate !== "undefined" ? clearImmediate : clearTimeout
         };
     }
 

src/harness/unittests/matchFiles.ts

@@ -91,6 +91,12 @@ namespace ts {
 
     const defaultExcludes = ["node_modules", "bower_components", "jspm_packages"];
 
+    function assertParsed(actual: ts.ParsedCommandLine, expected: ts.ParsedCommandLine): void {
+        assert.deepEqual(actual.fileNames, expected.fileNames);
+        assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
+        assert.deepEqual(actual.errors, expected.errors);
+    }
+
     describe("matchFiles", () => {
         describe("with literal file list", () => {
             it("without exclusions", () => {
@@ -110,9 +116,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("missing files are still present", () => {
                 const json = {
@@ -131,9 +135,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("are not removed due to excludes", () => {
                 const json = {
@@ -155,9 +157,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
         });
 
@@ -179,9 +179,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with non .ts file extensions are excluded", () => {
                 const json = {
@@ -200,9 +198,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with missing files are excluded", () => {
                 const json = {
@@ -221,9 +217,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with literal excludes", () => {
                 const json = {
@@ -244,9 +238,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with wildcard excludes", () => {
                 const json = {
@@ -274,9 +266,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with recursive excludes", () => {
                 const json = {
@@ -303,9 +293,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with case sensitive exclude", () => {
                 const json = {
@@ -325,9 +313,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseSensitiveHost, caseSensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and no exclusions", () => {
                 const json = {
@@ -349,9 +335,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and exclusions", () => {
                 const json = {
@@ -378,9 +362,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and empty exclude", () => {
                 const json = {
@@ -406,9 +388,7 @@ namespace ts {
                     wildcardDirectories: {},
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
         });
 
@@ -432,9 +412,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("`*` matches only ts files", () => {
                 const json = {
@@ -455,9 +433,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("`?` matches only a single character", () => {
                 const json = {
@@ -477,9 +453,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with recursive directory", () => {
                 const json = {
@@ -501,9 +475,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with multiple recursive directories", () => {
                 const json = {
@@ -527,9 +499,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("case sensitive", () => {
                 const json = {
@@ -548,9 +518,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseSensitiveHost, caseSensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with missing files are excluded", () => {
                 const json = {
@@ -570,9 +538,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("always include literal files", () => {
                 const json = {
@@ -597,9 +563,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude folders", () => {
                 const json = {
@@ -624,9 +588,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and no exclusions", () => {
                 const json = {
@@ -645,9 +607,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and exclusions", () => {
                 const json = {
@@ -671,9 +631,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with common package folders and empty exclude", () => {
                 const json = {
@@ -696,9 +654,7 @@ namespace ts {
                     },
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveCommonFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude .js files when allowJs=false", () => {
                 const json = {
@@ -723,9 +679,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include .js files when allowJs=true", () => {
                 const json = {
@@ -750,9 +704,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include explicitly listed .min.js files when allowJs=true", () => {
                 const json = {
@@ -777,9 +729,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include paths outside of the project", () => {
                 const json = {
@@ -803,9 +753,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include paths outside of the project using relative paths", () => {
                 const json = {
@@ -828,9 +776,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude paths outside of the project using relative paths", () => {
                 const json = {
@@ -851,9 +797,7 @@ namespace ts {
                     wildcardDirectories: {}
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("include files with .. in their name", () => {
                 const json = {
@@ -873,9 +817,7 @@ namespace ts {
                     wildcardDirectories: {}
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude files with .. in their name", () => {
                 const json = {
@@ -897,9 +839,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=none, allowJs=false", () => {
                 const json = {
@@ -922,9 +862,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=preserve, allowJs=false", () => {
                 const json = {
@@ -949,9 +887,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=none, allowJs=true", () => {
                 const json = {
@@ -976,9 +912,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("with jsx=preserve, allowJs=true", () => {
                 const json = {
@@ -1005,9 +939,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveMixedExtensionHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             it("exclude .min.js files using wildcards", () => {
                 const json = {
@@ -1034,9 +966,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             describe("with trailing recursive directory", () => {
                 it("in includes", () => {
@@ -1056,9 +986,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("in excludes", () => {
                     const json = {
@@ -1079,9 +1007,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
             });
             describe("with multiple recursive directory patterns", () => {
@@ -1102,9 +1028,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("in excludes", () => {
                     const json = {
@@ -1131,9 +1055,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
             });
 
@@ -1155,9 +1077,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
 
                 it("in includes after a subdirectory", () => {
@@ -1177,9 +1097,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
 
                 it("in excludes immediately after", () => {
@@ -1207,9 +1125,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
 
                 it("in excludes after a subdirectory", () => {
@@ -1237,9 +1153,25 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
+                });
+            });
+
+            describe("with implicit globbification", () => {
+                it("Expands 'z' to 'z/**/*'", () => {
+                    const json = {
+                        include: ["z"]
+                    };
+                    const expected: ts.ParsedCommandLine = {
+                        options: {},
+                        errors: [],
+                        fileNames: [ "a.ts", "aba.ts", "abz.ts", "b.ts", "bba.ts", "bbz.ts" ].map(x => `c:/dev/z/${x}`),
+                        wildcardDirectories: {
+                            "c:/dev/z": ts.WatchDirectoryFlags.Recursive
+                        }
+                    };
+                    const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveHost, caseInsensitiveBasePath);
+                    assertParsed(actual, expected);
                 });
             });
         });
@@ -1264,9 +1196,7 @@ namespace ts {
                     }
                 };
                 const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                assert.deepEqual(actual.fileNames, expected.fileNames);
-                assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                assert.deepEqual(actual.errors, expected.errors);
+                assertParsed(actual, expected);
             });
             describe("that are explicitly included", () => {
                 it("without wildcards", () => {
@@ -1286,9 +1216,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("with recursive wildcards that match directories", () => {
                     const json = {
@@ -1310,9 +1238,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("with recursive wildcards that match nothing", () => {
                     const json = {
@@ -1334,9 +1260,7 @@ namespace ts {
                         }
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
                 it("with wildcard excludes that implicitly exclude dotted files", () => {
                     const json = {
@@ -1357,9 +1281,7 @@ namespace ts {
                         wildcardDirectories: {}
                     };
                     const actual = ts.parseJsonConfigFileContent(json, caseInsensitiveDottedFoldersHost, caseInsensitiveBasePath, undefined, caseInsensitiveTsconfigPath);
-                    assert.deepEqual(actual.fileNames, expected.fileNames);
-                    assert.deepEqual(actual.wildcardDirectories, expected.wildcardDirectories);
-                    assert.deepEqual(actual.errors, expected.errors);
+                    assertParsed(actual, expected);
                 });
             });
         });

src/harness/unittests/moduleResolution.ts

@@ -1,7 +1,7 @@
 /// <reference path="..\harness.ts" />
 
 namespace ts {
-    export function checkResolvedModule(expected: ResolvedModule, actual: ResolvedModule): boolean {
+    export function checkResolvedModule(expected: ResolvedModuleFull, actual: ResolvedModuleFull): boolean {
         if (!expected === !actual) {
             if (expected) {
                 assert.isTrue(expected.resolvedFileName === actual.resolvedFileName, `'resolvedFileName': expected '${expected.resolvedFileName}' to be equal to '${actual.resolvedFileName}'`);
@@ -13,13 +13,13 @@ namespace ts {
         return false;
     }
 
-    export function checkResolvedModuleWithFailedLookupLocations(actual: ResolvedModuleWithFailedLookupLocations, expectedResolvedModule: ResolvedModule, expectedFailedLookupLocations: string[]): void {
+    export function checkResolvedModuleWithFailedLookupLocations(actual: ResolvedModuleWithFailedLookupLocations, expectedResolvedModule: ResolvedModuleFull, expectedFailedLookupLocations: string[]): void {
         assert.isTrue(actual.resolvedModule !== undefined, "module should be resolved");
         checkResolvedModule(actual.resolvedModule, expectedResolvedModule);
         assert.deepEqual(actual.failedLookupLocations, expectedFailedLookupLocations);
     }
 
-    export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport = false): ResolvedModule {
+    export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport = false): ResolvedModuleFull {
         return { resolvedFileName, extension: extensionFromPath(resolvedFileName), isExternalLibraryImport };
     }
 

src/harness/unittests/session.ts

@@ -150,7 +150,8 @@ namespace ts.server {
                         target: ScriptTarget.ES5,
                         jsx: JsxEmit.React,
                         newLine: NewLineKind.LineFeed,
-                        moduleResolution: ModuleResolutionKind.NodeJs
+                        moduleResolution: ModuleResolutionKind.NodeJs,
+                        allowNonTsExtensions: true // injected by tsserver
                     });
             });
         });

src/harness/unittests/tsserverProjectSystem.ts

@@ -2471,4 +2471,38 @@ namespace ts.projectSystem {
 
         });
     });
+
+    describe("Inferred projects", () => {
+        it("should support files without extensions", () => {
+            const f = {
+                path: "/a/compile",
+                content: "let x = 1"
+            };
+            const host = createServerHost([f]);
+            const session = createSession(host);
+            session.executeCommand(<server.protocol.SetCompilerOptionsForInferredProjectsRequest>{
+                seq: 1,
+                type: "request",
+                command: "compilerOptionsForInferredProjects",
+                arguments: {
+                    options: {
+                        allowJs: true
+                    }
+                }
+            });
+            session.executeCommand(<server.protocol.OpenRequest>{
+                seq: 2,
+                type: "request",
+                command: "open",
+                arguments: {
+                    file: f.path,
+                    fileContent: f.content,
+                    scriptKindName: "JS"
+                }
+            });
+            const projectService = session.getProjectService();
+            checkNumberOfProjects(projectService, { inferredProjects: 1 });
+            checkProjectActualFiles(projectService.inferredProjects[0], [f.path]);
+        });
+    });
 }

src/lib/dom.generated.d.ts

@@ -1679,6 +1679,7 @@ interface CSSStyleDeclaration {
     writingMode: string | null;
     zIndex: string | null;
     zoom: string | null;
+    resize: string | null;
     getPropertyPriority(propertyName: string): string;
     getPropertyValue(propertyName: string): string;
     item(index: number): string;
@@ -1748,6 +1749,7 @@ declare var CanvasGradient: {
 }
 
 interface CanvasPattern {
+    setTransform(matrix: SVGMatrix): void;
 }
 
 declare var CanvasPattern: {
@@ -2173,7 +2175,7 @@ interface DataTransfer {
     effectAllowed: string;
     readonly files: FileList;
     readonly items: DataTransferItemList;
-    readonly types: DOMStringList;
+    readonly types: string[];
     clearData(format?: string): boolean;
     getData(format: string): string;
     setData(format: string, data: string): boolean;
@@ -7584,7 +7586,7 @@ declare var IDBCursorWithValue: {
 
 interface IDBDatabase extends EventTarget {
     readonly name: string;
-    readonly objectStoreNames: DOMStringList;
+    readonly objectStoreNames: string[];
     onabort: (this: this, ev: Event) => any;
     onerror: (this: this, ev: ErrorEvent) => any;
     version: number;
@@ -7650,7 +7652,7 @@ declare var IDBKeyRange: {
 }
 
 interface IDBObjectStore {
-    readonly indexNames: DOMStringList;
+    readonly indexNames: string[];
     keyPath: string | string[];
     readonly name: string;
     readonly transaction: IDBTransaction;
@@ -8602,7 +8604,7 @@ interface MouseEvent extends UIEvent {
     readonly x: number;
     readonly y: number;
     getModifierState(keyArg: string): boolean;
-    initMouseEvent(typeArg: string, canBubbleArg: boolean, cancelableArg: boolean, viewArg: Window, detailArg: number, screenXArg: number, screenYArg: number, clientXArg: number, clientYArg: number, ctrlKeyArg: boolean, altKeyArg: boolean, shiftKeyArg: boolean, metaKeyArg: boolean, buttonArg: number, relatedTargetArg: EventTarget): void;
+    initMouseEvent(typeArg: string, canBubbleArg: boolean, cancelableArg: boolean, viewArg: Window, detailArg: number, screenXArg: number, screenYArg: number, clientXArg: number, clientYArg: number, ctrlKeyArg: boolean, altKeyArg: boolean, shiftKeyArg: boolean, metaKeyArg: boolean, buttonArg: number, relatedTargetArg: EventTarget | null): void;
 }
 
 declare var MouseEvent: {
@@ -8715,6 +8717,7 @@ interface Navigator extends Object, NavigatorID, NavigatorOnLine, NavigatorConte
     readonly plugins: PluginArray;
     readonly pointerEnabled: boolean;
     readonly webdriver: boolean;
+    readonly hardwareConcurrency: number;
     getGamepads(): Gamepad[];
     javaEnabled(): boolean;
     msLaunchUri(uri: string, successCallback?: MSLaunchUriCallback, noHandlerCallback?: MSLaunchUriCallback): void;
@@ -8732,18 +8735,18 @@ interface Node extends EventTarget {
     readonly attributes: NamedNodeMap;
     readonly baseURI: string | null;
     readonly childNodes: NodeList;
-    readonly firstChild: Node;
-    readonly lastChild: Node;
+    readonly firstChild: Node | null;
+    readonly lastChild: Node | null;
     readonly localName: string | null;
     readonly namespaceURI: string | null;
-    readonly nextSibling: Node;
+    readonly nextSibling: Node | null;
     readonly nodeName: string;
     readonly nodeType: number;
     nodeValue: string | null;
     readonly ownerDocument: Document;
-    readonly parentElement: HTMLElement;
-    readonly parentNode: Node;
-    readonly previousSibling: Node;
+    readonly parentElement: HTMLElement | null;
+    readonly parentNode: Node | null;
+    readonly previousSibling: Node | null;
     textContent: string | null;
     appendChild(newChild: Node): Node;
     cloneNode(deep?: boolean): Node;
@@ -12853,7 +12856,7 @@ interface Window extends EventTarget, WindowTimers, WindowSessionStorage, Window
     readonly devicePixelRatio: number;
     readonly doNotTrack: string;
     readonly document: Document;
-    event: Event;
+    event: Event | undefined;
     readonly external: External;
     readonly frameElement: Element;
     readonly frames: Window;
@@ -13155,6 +13158,7 @@ interface XMLHttpRequest extends EventTarget, XMLHttpRequestEventTarget {
     readonly upload: XMLHttpRequestUpload;
     withCredentials: boolean;
     msCaching?: string;
+    readonly responseURL: string;
     abort(): void;
     getAllResponseHeaders(): string;
     getResponseHeader(header: string): string | null;
@@ -14301,7 +14305,7 @@ declare var defaultStatus: string;
 declare var devicePixelRatio: number;
 declare var doNotTrack: string;
 declare var document: Document;
-declare var event: Event;
+declare var event: Event | undefined;
 declare var external: External;
 declare var frameElement: Element;
 declare var frames: Window;

src/lib/webworker.generated.d.ts

@@ -341,7 +341,7 @@ declare var IDBCursorWithValue: {
 
 interface IDBDatabase extends EventTarget {
     readonly name: string;
-    readonly objectStoreNames: DOMStringList;
+    readonly objectStoreNames: string[];
     onabort: (this: this, ev: Event) => any;
     onerror: (this: this, ev: ErrorEvent) => any;
     version: number;
@@ -407,7 +407,7 @@ declare var IDBKeyRange: {
 }
 
 interface IDBObjectStore {
-    readonly indexNames: DOMStringList;
+    readonly indexNames: string[];
     keyPath: string | string[];
     readonly name: string;
     readonly transaction: IDBTransaction;
@@ -740,6 +740,7 @@ interface XMLHttpRequest extends EventTarget, XMLHttpRequestEventTarget {
     readonly upload: XMLHttpRequestUpload;
     withCredentials: boolean;
     msCaching?: string;
+    readonly responseURL: string;
     abort(): void;
     getAllResponseHeaders(): string;
     getResponseHeader(header: string): string | null;
@@ -902,6 +903,7 @@ declare var WorkerLocation: {
 }
 
 interface WorkerNavigator extends Object, NavigatorID, NavigatorOnLine {
+    readonly hardwareConcurrency: number;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
 }
 

src/server/editorServices.ts

@@ -298,6 +298,9 @@ namespace ts.server {
 
         setCompilerOptionsForInferredProjects(projectCompilerOptions: protocol.ExternalProjectCompilerOptions): void {
             this.compilerOptionsForInferredProjects = convertCompilerOptions(projectCompilerOptions);
+            // always set 'allowNonTsExtensions' for inferred projects since user cannot configure it from the outside
+            // previously we did not expose a way for user to change these settings and this option was enabled by default
+            this.compilerOptionsForInferredProjects.allowNonTsExtensions = true;
             this.compileOnSaveForInferredProjects = projectCompilerOptions.compileOnSave;
             for (const proj of this.inferredProjects) {
                 proj.setCompilerOptions(this.compilerOptionsForInferredProjects);
@@ -1008,7 +1011,7 @@ namespace ts.server {
             const useExistingProject = this.useSingleInferredProject && this.inferredProjects.length;
             const project = useExistingProject
                 ? this.inferredProjects[0]
-                : new InferredProject(this, this.documentRegistry, /*languageServiceEnabled*/ true, this.compilerOptionsForInferredProjects, /*compileOnSaveEnabled*/ this.compileOnSaveForInferredProjects);
+                : new InferredProject(this, this.documentRegistry, /*languageServiceEnabled*/ true, this.compilerOptionsForInferredProjects);
 
             project.addRoot(root);
 

src/server/lsHost.ts

@@ -151,7 +151,7 @@ namespace ts.server {
                 m => m.resolvedTypeReferenceDirective, r => r.resolvedFileName,  /*logChanges*/ false);
         }
 
-        resolveModuleNames(moduleNames: string[], containingFile: string): ResolvedModule[] {
+        resolveModuleNames(moduleNames: string[], containingFile: string): ResolvedModuleFull[] {
             return this.resolveNamesWithLocalCache(moduleNames, containingFile, this.resolvedModuleNames, this.resolveModuleName,
                 m => m.resolvedModule, r => r.resolvedFileName, /*logChanges*/ true);
         }

src/server/project.ts

@@ -666,14 +666,14 @@ namespace ts.server {
         // Used to keep track of what directories are watched for this project
         directoriesWatchedForTsconfig: string[] = [];
 
-        constructor(projectService: ProjectService, documentRegistry: ts.DocumentRegistry, languageServiceEnabled: boolean, compilerOptions: CompilerOptions, public compileOnSaveEnabled: boolean) {
+        constructor(projectService: ProjectService, documentRegistry: ts.DocumentRegistry, languageServiceEnabled: boolean, compilerOptions: CompilerOptions) {
             super(ProjectKind.Inferred,
                 projectService,
                 documentRegistry,
                 /*files*/ undefined,
                 languageServiceEnabled,
                 compilerOptions,
-                compileOnSaveEnabled);
+                /*compileOnSaveEnabled*/ false);
 
             this.inferredProjectName = makeInferredProjectName(InferredProject.NextId);
             InferredProject.NextId++;

src/services/services.ts

@@ -467,7 +467,7 @@ namespace ts {
         public languageVariant: LanguageVariant;
         public identifiers: Map<string>;
         public nameTable: Map<number>;
-        public resolvedModules: Map<ResolvedModule>;
+        public resolvedModules: Map<ResolvedModuleFull>;
         public resolvedTypeReferenceDirectiveNames: Map<ResolvedTypeReferenceDirective>;
         public imports: LiteralExpression[];
         public moduleAugmentations: LiteralExpression[];

src/services/shims.ts

@@ -316,7 +316,7 @@ namespace ts {
         private loggingEnabled = false;
         private tracingEnabled = false;
 
-        public resolveModuleNames: (moduleName: string[], containingFile: string) => ResolvedModule[];
+        public resolveModuleNames: (moduleName: string[], containingFile: string) => ResolvedModuleFull[];
         public resolveTypeReferenceDirectives: (typeDirectiveNames: string[], containingFile: string) => ResolvedTypeReferenceDirective[];
         public directoryExists: (directoryName: string) => boolean;
 

tests/baselines/reference/ES5For-of12.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts(1,7): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts(1,7): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts (1 errors) ====
     for ([""] of [[""]]) { }
           ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.

tests/baselines/reference/abstractPropertyNegative.errors.txt

@@ -6,7 +6,7 @@ tests/cases/compiler/abstractPropertyNegative.ts(13,7): error TS2515: Non-abstra
 tests/cases/compiler/abstractPropertyNegative.ts(13,7): error TS2515: Non-abstract class 'C' does not implement inherited abstract member 'readonlyProp' from class 'B'.
 tests/cases/compiler/abstractPropertyNegative.ts(15,5): error TS1244: Abstract methods can only appear within an abstract class.
 tests/cases/compiler/abstractPropertyNegative.ts(16,37): error TS1005: '{' expected.
-tests/cases/compiler/abstractPropertyNegative.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/abstractPropertyNegative.ts(19,3): error TS2540: Cannot assign to 'ro' because it is a constant or a read-only property.
 tests/cases/compiler/abstractPropertyNegative.ts(24,7): error TS2415: Class 'WrongTypePropertyImpl' incorrectly extends base class 'WrongTypeProperty'.
   Types of property 'num' are incompatible.
     Type 'string' is not assignable to type 'number'.
@@ -58,8 +58,8 @@ tests/cases/compiler/abstractPropertyNegative.ts(41,18): error TS2676: Accessors
     }
     let c = new C();
     c.ro = "error: lhs of assignment can't be readonly";
-    ~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~
+!!! error TS2540: Cannot assign to 'ro' because it is a constant or a read-only property.
     
     abstract class WrongTypeProperty {
         abstract num: number;

tests/baselines/reference/arithAssignTyping.errors.txt

@@ -1,15 +1,15 @@
-tests/cases/compiler/arithAssignTyping.ts(3,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/arithAssignTyping.ts(4,1): error TS2365: Operator '+=' cannot be applied to types 'typeof f' and '1'.
-tests/cases/compiler/arithAssignTyping.ts(5,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(6,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(7,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(8,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(9,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(10,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(11,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(12,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(13,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+tests/cases/compiler/arithAssignTyping.ts(3,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(4,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(5,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(6,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(7,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(8,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(9,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(10,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(11,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(12,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(13,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2539: Cannot assign to 'f' because it is not a variable.
 
 
 ==== tests/cases/compiler/arithAssignTyping.ts (12 errors) ====
@@ -17,37 +17,37 @@ tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2362: The left-hand sid
     
     f += ''; // error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f += 1; // error
-    ~~~~~~
-!!! error TS2365: Operator '+=' cannot be applied to types 'typeof f' and '1'.
+    ~
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f -= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f *= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f /= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f %= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f &= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f |= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f <<= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f >>= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f >>>= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     f ^= 1; // error
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.

tests/baselines/reference/assignAnyToEveryType.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/any/assignAnyToEveryType.ts (1 errors) ====
@@ -44,7 +44,7 @@ tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2364: I
     
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function k<T>(a: T) {
         a = x;

tests/baselines/reference/assignToEnum.errors.txt

@@ -1,22 +1,22 @@
-tests/cases/compiler/assignToEnum.ts(2,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignToEnum.ts(3,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignToEnum.ts(4,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/assignToEnum.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/assignToEnum.ts(2,1): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/compiler/assignToEnum.ts(3,1): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/compiler/assignToEnum.ts(4,3): error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
+tests/cases/compiler/assignToEnum.ts(5,3): error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/assignToEnum.ts (4 errors) ====
     enum A { foo, bar }
     A = undefined;  // invalid LHS
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     A = A.bar;      // invalid LHS
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     A.foo = 1;      // invalid LHS
-    ~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
     A.foo = A.bar;  // invalid LHS
-    ~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'foo' because it is a constant or a read-only property.
     
     

tests/baselines/reference/assignToExistingClass.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2539: Cannot assign to 'Mocked' because it is not a variable.
 
 
 ==== tests/cases/compiler/assignToExistingClass.ts (1 errors) ====
@@ -11,7 +11,7 @@ tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2364: Invalid left-
             willThrowError() {
                 Mocked = Mocked || function () { // => Error: Invalid left-hand side of assignment expression.
                 ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'Mocked' because it is not a variable.
                     return { myProp: "test" };
                 };
             }

tests/baselines/reference/assignToInvalidLHS.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/assignToInvalidLHS.ts(4,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignToInvalidLHS.ts(4,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/compiler/assignToInvalidLHS.ts (1 errors) ====
@@ -7,4 +7,4 @@ tests/cases/compiler/assignToInvalidLHS.ts(4,9): error TS2364: Invalid left-hand
     // Below is actually valid JavaScript (see http://es5.github.com/#x8.7 ), even though will always fail at runtime with 'invalid left-hand side'
     var x = new y = 5;
             ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.

tests/baselines/reference/assignmentLHSIsValue.errors.txt

@@ -1,42 +1,42 @@
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(6,21): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7,13): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(8,21): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(11,18): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(13,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(19,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(22,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(24,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(27,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(28,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(29,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(30,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(31,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(32,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(6,21): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7,13): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(8,21): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(11,18): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(13,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(19,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(22,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(24,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(27,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(28,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(29,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(30,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(31,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(32,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(35,3): error TS7028: Unused label.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(35,9): error TS1128: Declaration or statement expected.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,2): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,6): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,2): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(38,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(42,36): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(44,19): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(46,27): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(50,20): error TS1128: Declaration or statement expected.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(51,11): error TS1005: ';' expected.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(54,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(57,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(58,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(59,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(60,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(61,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(62,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(63,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(64,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(65,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(66,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(67,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(68,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(69,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(70,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(54,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(57,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(58,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(59,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(60,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(61,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(62,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(63,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(64,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(65,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(66,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(67,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(68,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(69,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(70,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts (39 errors) ====
@@ -47,61 +47,61 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     class C {
         constructor() { this = value; }
                         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         foo() { this = value; }
                 ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         static sfoo() { this = value; }
                         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
     
     function foo() { this = value; }
                      ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     this = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // identifiers: module, class, enum, function
     module M { export var a; }
     M = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     C = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { }
     E = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     foo = value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     
     // literals
     null = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     true = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     false = value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     0 = value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     '' = value;
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     /d+/ = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // object literals
     { a: 0} = value;
@@ -113,9 +113,9 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     // array literals
     ['', ''] = value;
      ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
          ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // super
     class Derived extends C {
@@ -143,48 +143,48 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     // function calls
     foo() = value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // parentheses, the containted expression is value
     (this) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (M) = value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (C) = value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (E) = value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (foo) = value;
-    ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (true) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (0) = value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ('') = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (/d+/) = value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ({}) = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ([]) = value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (function baz() { }) = value;
     ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (foo()) = value;
     ~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.

tests/baselines/reference/assignmentToFunction.errors.txt

@@ -1,12 +1,12 @@
-tests/cases/compiler/assignmentToFunction.ts(2,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignmentToFunction.ts(2,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
+tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2539: Cannot assign to 'bar' because it is not a variable.
 
 
 ==== tests/cases/compiler/assignmentToFunction.ts (2 errors) ====
     function fn() { }
     fn = () => 3;
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     
     module foo {
         function xyz() {
@@ -14,6 +14,6 @@ tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2364: Invalid left-ha
             }
             bar = null;
             ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'bar' because it is not a variable.
         }
     }

tests/baselines/reference/assignmentToParenthesizedExpression1.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,2): error TS2695: Left side of comma operator is unused and has no side effects.
 
 
@@ -6,6 +6,6 @@ tests/cases/compiler/assignmentToParenthesizedExpression1.ts(2,2): error TS2695:
     var x;
     (1, x)=0;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
      ~
 !!! error TS2695: Left side of comma operator is unused and has no side effects.

tests/baselines/reference/assignmentToParenthesizedIdentifiers.errors.txt

@@ -3,9 +3,9 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(13,1): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(14,1): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(15,1): error TS2322: Type '""' is not assignable to type 'number'.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(25,5): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(18,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(25,5): error TS2539: Cannot assign to 'M3' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(31,1): error TS2322: Type '{ x: string; }' is not assignable to type 'typeof M3'.
   Types of property 'x' are incompatible.
     Type 'string' is not assignable to type 'number'.
@@ -15,8 +15,8 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(33,1): error TS2322: Type '{ x: string; }' is not assignable to type 'typeof M3'.
   Types of property 'x' are incompatible.
     Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(37,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(38,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(37,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(38,2): error TS2539: Cannot assign to 'fn' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(43,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(44,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(48,5): error TS2322: Type '""' is not assignable to type 'number'.
@@ -24,10 +24,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(54,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(55,5): error TS2322: Type '""' is not assignable to type 'number'.
 tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(56,5): error TS2322: Type '""' is not assignable to type 'number'.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(62,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(63,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(69,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(70,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(62,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(63,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(69,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts(70,2): error TS2539: Cannot assign to 'C' because it is not a variable.
 
 
 ==== tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesizedIdentifiers.ts (24 errors) ====
@@ -59,10 +59,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     
     M = { y: 3 }; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (M) = { y: 3 }; // Error
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     module M2 {
         export module M3 {
@@ -71,7 +71,7 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     
         M3 = { x: 3 }; // Error
         ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M3' because it is not a variable.
     }
     M2.M3 = { x: 3 }; // OK
     (M2).M3 = { x: 3 }; // OK
@@ -97,10 +97,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     function fn() { }
     fn = () => 3; // Bug 823548: Should be error (fn is not a reference)
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     (fn) = () => 3; // Should be error
-    ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~~
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     
     function fn2(x: number, y: { t: number }) {
         x = 3;
@@ -140,10 +140,10 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     }
     E = undefined; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (E) = undefined; // Error
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     class C {
     
@@ -151,8 +151,8 @@ tests/cases/conformance/expressions/valuesAndReferences/assignmentToParenthesize
     
     C = undefined; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (C) = undefined; // Error
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     

tests/baselines/reference/assignmentToReferenceTypes.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/compiler/assignmentToReferenceTypes.ts(5,1): error TS2304: Cannot find name 'M'.
-tests/cases/compiler/assignmentToReferenceTypes.ts(9,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignmentToReferenceTypes.ts(13,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/compiler/assignmentToReferenceTypes.ts(16,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/assignmentToReferenceTypes.ts(9,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/compiler/assignmentToReferenceTypes.ts(13,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/compiler/assignmentToReferenceTypes.ts(16,1): error TS2539: Cannot assign to 'f' because it is not a variable.
 
 
 ==== tests/cases/compiler/assignmentToReferenceTypes.ts (4 errors) ====
@@ -17,18 +17,18 @@ tests/cases/compiler/assignmentToReferenceTypes.ts(16,1): error TS2364: Invalid
     }
     C = null;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E {
     }
     E = null;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     function f() { }
     f = null;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     
     var x = 1;
     x = null;

tests/baselines/reference/assignments.errors.txt

@@ -1,8 +1,8 @@
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(11,1): error TS2304: Cannot find name 'M'.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(14,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(14,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(17,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(18,3): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(21,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
 tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(31,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
 
 
@@ -24,20 +24,20 @@ tests/cases/conformance/expressions/valuesAndReferences/assignments.ts(31,1): er
     class C { }
     C = null; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { A }
     E = null; // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E.A = null; // OK per spec, Error per implementation (509581)
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     function fn() { }
     fn = null; // Should be error
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
     
     var v;
     v = null; // OK

tests/baselines/reference/asyncAliasReturnType_es5.errors.txt

@@ -0,0 +1,10 @@
+tests/cases/conformance/async/es5/asyncAliasReturnType_es5.ts(3,21): error TS1055: Type 'PromiseAlias' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+
+
+==== tests/cases/conformance/async/es5/asyncAliasReturnType_es5.ts (1 errors) ====
+    type PromiseAlias<T> = Promise<T>;
+    
+    async function f(): PromiseAlias<void> {
+                        ~~~~~~~~~~~~~~~~~~
+!!! error TS1055: Type 'PromiseAlias' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+    }

tests/baselines/reference/asyncAwaitIsolatedModules_es5.js

@@ -77,6 +77,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var _this = this;
+var missing_1 = require("missing");
 function f0() {
     return __awaiter(this, void 0, void 0, function () { return __generator(this, function (_a) {
         return [2 /*return*/];

tests/baselines/reference/asyncFunctionDeclaration15_es5.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(6,23): error TS1055: Type '{}' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(7,23): error TS1055: Type 'any' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(8,23): error TS1055: Type 'number' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(9,23): error TS1055: Type 'PromiseLike' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type.
-tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(6,23): error TS1055: Type '{}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(7,23): error TS1055: Type 'any' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(8,23): error TS1055: Type 'number' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(9,23): error TS1055: Type 'PromiseLike' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
   Type 'Thenable' is not assignable to type 'PromiseLike<any>'.
     Types of property 'then' are incompatible.
       Type '() => void' is not assignable to type '{ (onfulfilled?: (value: any) => any, onrejected?: (reason: any) => any): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => any, onrejected: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => TResult | PromiseLike<TResult>, onrejected?: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<TResult>; <TResult1, TResult2>(onfulfilled: (value: any) => TResult1 | PromiseLike<TResult1>, onrejected: (reason: any) => TResult2 | PromiseLike<TResult2>): PromiseLike<TResult1 | TResult2>; }'.
@@ -20,21 +20,21 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration1
     async function fn1() { } // valid: Promise<void>
     async function fn2(): { } { } // error
                           ~~~
-!!! error TS1055: Type '{}' is not a valid async function return type.
+!!! error TS1055: Type '{}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn3(): any { } // error
                           ~~~
-!!! error TS1055: Type 'any' is not a valid async function return type.
+!!! error TS1055: Type 'any' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn4(): number { } // error
                           ~~~~~~
-!!! error TS1055: Type 'number' is not a valid async function return type.
+!!! error TS1055: Type 'number' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn5(): PromiseLike<void> { } // error
                           ~~~~~~~~~~~~~~~~~
-!!! error TS1055: Type 'PromiseLike' is not a valid async function return type.
+!!! error TS1055: Type 'PromiseLike' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
     async function fn6(): Thenable { } // error
                           ~~~~~~~~
-!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type.
+!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
                           ~~~~~~~~
-!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type.
+!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
 !!! error TS1055:   Type 'Thenable' is not assignable to type 'PromiseLike<any>'.
 !!! error TS1055:     Types of property 'then' are incompatible.
 !!! error TS1055:       Type '() => void' is not assignable to type '{ (onfulfilled?: (value: any) => any, onrejected?: (reason: any) => any): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => any, onrejected: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<any>; <TResult>(onfulfilled: (value: any) => TResult | PromiseLike<TResult>, onrejected?: (reason: any) => TResult | PromiseLike<TResult>): PromiseLike<TResult>; <TResult1, TResult2>(onfulfilled: (value: any) => TResult1 | PromiseLike<TResult1>, onrejected: (reason: any) => TResult2 | PromiseLike<TResult2>): PromiseLike<TResult1 | TResult2>; }'.

tests/baselines/reference/asyncFunctionNoReturnType.errors.txt

@@ -1,5 +1,5 @@
 error TS2318: Cannot find global type 'Promise'.
-tests/cases/compiler/asyncFunctionNoReturnType.ts(1,1): error TS1057: An async function or method must have a valid awaitable return type.
+tests/cases/compiler/asyncFunctionNoReturnType.ts(1,1): error TS2697: An async function or method must return a 'Promise'. Make sure you have a declaration for 'Promise' or include 'ES2015' in your `--lib` option.
 tests/cases/compiler/asyncFunctionNoReturnType.ts(1,1): error TS7030: Not all code paths return a value.
 tests/cases/compiler/asyncFunctionNoReturnType.ts(2,9): error TS2304: Cannot find name 'window'.
 tests/cases/compiler/asyncFunctionNoReturnType.ts(3,9): error TS7030: Not all code paths return a value.
@@ -9,7 +9,7 @@ tests/cases/compiler/asyncFunctionNoReturnType.ts(3,9): error TS7030: Not all co
 ==== tests/cases/compiler/asyncFunctionNoReturnType.ts (4 errors) ====
     async () => {
     ~~~~~~~~~~~~~
-!!! error TS1057: An async function or method must have a valid awaitable return type.
+!!! error TS2697: An async function or method must return a 'Promise'. Make sure you have a declaration for 'Promise' or include 'ES2015' in your `--lib` option.
     ~~~~~~~~~~~~~
 !!! error TS7030: Not all code paths return a value.
         if (window)

tests/baselines/reference/asyncIIFE.js

@@ -0,0 +1,28 @@
+//// [asyncIIFE.ts]
+
+function f1() {
+    (async () => {
+        await 10
+        throw new Error();
+    })();
+
+    var x = 1;
+}
+
+
+//// [asyncIIFE.js]
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments)).next());
+    });
+};
+function f1() {
+    (() => __awaiter(this, void 0, void 0, function* () {
+        yield 10;
+        throw new Error();
+    }))();
+    var x = 1;
+}

tests/baselines/reference/asyncIIFE.symbols

@@ -0,0 +1,16 @@
+=== tests/cases/compiler/asyncIIFE.ts ===
+
+function f1() {
+>f1 : Symbol(f1, Decl(asyncIIFE.ts, 0, 0))
+
+    (async () => {
+        await 10
+        throw new Error();
+>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+    })();
+
+    var x = 1;
+>x : Symbol(x, Decl(asyncIIFE.ts, 7, 7))
+}
+

tests/baselines/reference/asyncIIFE.types

@@ -0,0 +1,25 @@
+=== tests/cases/compiler/asyncIIFE.ts ===
+
+function f1() {
+>f1 : () => void
+
+    (async () => {
+>(async () => {        await 10        throw new Error();    })() : Promise<never>
+>(async () => {        await 10        throw new Error();    }) : () => Promise<never>
+>async () => {        await 10        throw new Error();    } : () => Promise<never>
+
+        await 10
+>await 10 : 10
+>10 : 10
+
+        throw new Error();
+>new Error() : Error
+>Error : ErrorConstructor
+
+    })();
+
+    var x = 1;
+>x : number
+>1 : 1
+}
+

tests/baselines/reference/compoundAssignmentLHSIsValue.errors.txt

@@ -1,37 +1,37 @@
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(8,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(9,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(9,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(12,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(13,9): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(13,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(16,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(17,9): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(22,5): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(23,5): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(26,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(27,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(31,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(32,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(34,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(35,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(38,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(39,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(41,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(42,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(45,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(46,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(17,9): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(22,5): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(23,5): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(26,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(27,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(31,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(32,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(34,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(35,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(38,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(39,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(41,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(42,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(45,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(46,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(47,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(48,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(48,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(49,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(50,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(51,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(52,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(50,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(51,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(52,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(53,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(54,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(54,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(55,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(56,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(56,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(59,9): error TS1128: Declaration or statement expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(60,9): error TS1128: Declaration or statement expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(63,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(64,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(64,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(70,15): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(71,15): error TS1034: 'super' must be followed by an argument list or member access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(75,15): error TS1034: 'super' must be followed by an argument list or member access.
@@ -43,35 +43,35 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(88,11): error TS1005: ';' expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(89,11): error TS1005: ';' expected.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(92,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(93,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(96,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(97,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(98,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(99,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(100,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(101,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(102,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(103,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(104,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(105,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(106,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(107,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(93,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(96,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(97,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(98,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(99,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(100,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(101,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(102,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(103,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(104,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(105,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(106,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(107,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(108,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(109,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(110,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(111,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(109,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(110,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(111,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(112,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(113,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(113,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(114,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(115,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(115,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(116,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(117,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(117,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(118,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(119,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(119,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(120,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(121,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(121,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(122,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(123,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts(123,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsValue.ts (74 errors) ====
@@ -87,7 +87,7 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
             this += value;
             ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         }
         foo() {
             this *= value;
@@ -95,7 +95,7 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
             this += value;
             ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         }
         static sfoo() {
             this *= value;
@@ -103,94 +103,94 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
             this += value;
             ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         }
     }
     
     function foo() {
         this *= value;
         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
         this += value;
         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
     
     this *= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     this += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // identifiers: module, class, enum, function
     module M { export var a; }
     M *= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     M += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     C *= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     C += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { }
     E *= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     foo *= value;
     ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     foo += value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     
     // literals
     null *= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     null += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     true *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     true += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     false *= value;
     ~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     false += value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     0 *= value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     0 += value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     '' *= value;
     ~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     '' += value;
     ~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     /d+/ *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     /d+/ += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // object literals
     { a: 0} *= value;
@@ -206,7 +206,7 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ['', ''] += value;
     ~~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // super
     class Derived extends C {
@@ -259,90 +259,90 @@ tests/cases/conformance/expressions/assignmentOperator/compoundAssignmentLHSIsVa
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     foo() += value;
     ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // parentheses, the containted expression is value
     (this) *= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (this) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (M) *= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (M) += value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (C) *= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (C) += value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (E) *= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (E) += value;
-    ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (foo) *= value;
-    ~~~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (foo) += value;
-    ~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) *= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (null) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (true) *= value;
     ~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (true) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (0) *= value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (0) += value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ('') *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ('') += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (/d+/) *= value;
     ~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (/d+/) += value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ({}) *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ({}) += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ([]) *= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     ([]) += value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (function baz1() { }) *= value;
     ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (function baz2() { }) += value;
     ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (foo()) *= value;
     ~~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (foo()) += value;
     ~~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.

tests/baselines/reference/compoundExponentiationAssignmentLHSIsValue.errors.txt

@@ -1,16 +1,16 @@
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(7,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(10,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(13,9): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(18,5): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(25,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(27,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(30,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(32,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(35,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(18,5): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(21,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(25,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(27,1): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(30,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(32,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(35,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(36,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(37,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(38,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(38,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(39,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(40,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(43,3): error TS7028: Unused label.
@@ -22,14 +22,14 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(65,21): error TS1128: Declaration or statement expected.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(66,11): error TS1005: ';' expected.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(69,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(72,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(73,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(74,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(75,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(76,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(77,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(72,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(73,2): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(74,2): error TS2539: Cannot assign to 'C' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(75,2): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(76,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(77,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(78,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(79,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(79,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(80,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(81,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignmentLHSIsValue.ts(82,1): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -64,36 +64,36 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
     function foo() {
         this **= value;
         ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
     
     this **= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     
     // identifiers: module, class, enum, function
     module M { export var a; }
     M **= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     C **= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     enum E { }
     E **= value;
     ~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     
     foo **= value;
     ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     
     // literals
     null **= value;
     ~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     true **= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -102,7 +102,7 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     0 **= value;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     '' **= value;
     ~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
@@ -160,28 +160,28 @@ tests/cases/conformance/es7/exponentiationOperator/compoundExponentiationAssignm
     // parentheses, the containted expression is value
     (this) **= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (M) **= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     (C) **= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     (E) **= value;
-    ~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     (foo) **= value;
-    ~~~~~
-!!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
+     ~~~
+!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
     (null) **= value;
     ~~~~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (true) **= value;
     ~~~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
     (0) **= value;
     ~~~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     ('') **= value;
     ~~~~
 !!! error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.

tests/baselines/reference/concatClassAndString.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/concatClassAndString.ts(4,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/concatClassAndString.ts(4,1): error TS2539: Cannot assign to 'f' because it is not a variable.
 
 
 ==== tests/cases/compiler/concatClassAndString.ts (1 errors) ====
@@ -7,5 +7,5 @@ tests/cases/compiler/concatClassAndString.ts(4,1): error TS2364: Invalid left-ha
     
     f += '';
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'f' because it is not a variable.
     

tests/baselines/reference/constDeclarations-access.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/file2.ts(1,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/file2.ts(1,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/file1.ts (0 errors) ====
@@ -8,4 +8,4 @@ tests/cases/compiler/file2.ts(1,1): error TS2449: The operand of an increment or
 ==== tests/cases/compiler/file2.ts (1 errors) ====
     x++;
     ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.

tests/baselines/reference/constDeclarations-access2.errors.txt

@@ -1,20 +1,20 @@
-tests/cases/compiler/constDeclarations-access2.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(6,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(16,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(18,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(19,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(20,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(21,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access2.ts(23,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(5,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(6,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(7,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(8,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(9,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(10,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(11,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(12,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(13,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(14,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(15,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(16,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(18,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(19,1): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(20,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(21,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access2.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations-access2.ts (17 errors) ====
@@ -24,57 +24,57 @@ tests/cases/compiler/constDeclarations-access2.ts(23,3): error TS2449: The opera
     // Errors
     x = 1;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x += 2;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x -= 3;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x *= 4;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x /= 5;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x %= 6;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x <<= 7;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x >>= 8;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x >>>= 9;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x &= 10;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x |= 11;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x ^= 12;
     ~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     x++;
     ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     x--;
     ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++x;
       ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --x;
       ~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((x));
-      ~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = x + 1;

tests/baselines/reference/constDeclarations-access3.errors.txt

@@ -1,21 +1,21 @@
-tests/cases/compiler/constDeclarations-access3.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(16,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(21,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(22,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(23,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(24,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(26,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access3.ts(28,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(8,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(9,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(10,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(11,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(12,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(13,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(14,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(15,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(16,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(17,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(18,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(19,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(21,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(22,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(24,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(26,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access3.ts(28,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations-access3.ts (18 errors) ====
@@ -27,62 +27,62 @@ tests/cases/compiler/constDeclarations-access3.ts(28,1): error TS2450: Left-hand
     
     // Errors
     M.x = 1;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x += 2;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x -= 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x *= 4;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x /= 5;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x %= 6;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x <<= 7;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>= 8;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>>= 9;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x &= 10;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x |= 11;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x ^= 12;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M.x++;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x--;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((M.x));
-      ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M["x"] = 0;
-    ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = M.x + 1;

tests/baselines/reference/constDeclarations-access4.errors.txt

@@ -1,21 +1,21 @@
-tests/cases/compiler/constDeclarations-access4.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(16,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(21,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(22,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(23,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(24,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(26,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations-access4.ts(28,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(8,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(9,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(10,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(11,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(12,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(13,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(14,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(15,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(16,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(17,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(18,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(19,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(21,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(22,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(23,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(24,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(26,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations-access4.ts(28,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations-access4.ts (18 errors) ====
@@ -27,62 +27,62 @@ tests/cases/compiler/constDeclarations-access4.ts(28,1): error TS2450: Left-hand
     
     // Errors
     M.x = 1;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x += 2;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x -= 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x *= 4;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x /= 5;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x %= 6;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x <<= 7;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>= 8;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x >>>= 9;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x &= 10;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x |= 11;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x ^= 12;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M.x++;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     M.x--;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --M.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((M.x));
-      ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     M["x"] = 0;
-    ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = M.x + 1;

tests/baselines/reference/constDeclarations-access5.errors.txt

@@ -1,21 +1,21 @@
-tests/cases/compiler/constDeclarations_access_2.ts(4,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(6,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(10,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(11,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(12,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(13,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(14,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(15,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(17,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(18,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(19,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(20,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(22,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/constDeclarations_access_2.ts(24,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(4,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(5,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(6,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(7,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(8,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(9,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(10,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(11,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(12,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(13,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(14,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(15,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(17,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(18,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(19,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(20,5): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(22,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/constDeclarations_access_2.ts(24,3): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 
 
 ==== tests/cases/compiler/constDeclarations_access_2.ts (18 errors) ====
@@ -23,62 +23,62 @@ tests/cases/compiler/constDeclarations_access_2.ts(24,1): error TS2450: Left-han
     import m = require('constDeclarations_access_1');
     // Errors
     m.x = 1;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x += 2;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x -= 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x *= 4;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x /= 5;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x %= 6;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x <<= 7;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x >>= 8;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x >>>= 9;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x &= 10;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x |= 11;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x ^= 12;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m
     m.x++;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     m.x--;
-    ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     ++m.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     --m.x;
-      ~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+        ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     ++((m.x));
-      ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     m["x"] = 0;
-    ~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     
     // OK
     var a = m.x + 1;

tests/baselines/reference/constDeclarations-errors.errors.txt

@@ -5,7 +5,7 @@ tests/cases/compiler/constDeclarations-errors.ts(5,11): error TS1155: 'const' de
 tests/cases/compiler/constDeclarations-errors.ts(5,15): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(5,27): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(10,19): error TS2365: Operator '<' cannot be applied to types '0' and '1'.
-tests/cases/compiler/constDeclarations-errors.ts(10,27): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/compiler/constDeclarations-errors.ts(10,27): error TS2540: Cannot assign to 'c8' because it is a constant or a read-only property.
 tests/cases/compiler/constDeclarations-errors.ts(13,11): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(16,20): error TS1155: 'const' declarations must be initialized
 tests/cases/compiler/constDeclarations-errors.ts(16,25): error TS2365: Operator '<' cannot be applied to types '0' and '1'.
@@ -37,7 +37,7 @@ tests/cases/compiler/constDeclarations-errors.ts(16,25): error TS2365: Operator
                       ~~~~~~
 !!! error TS2365: Operator '<' cannot be applied to types '0' and '1'.
                               ~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'c8' because it is a constant or a read-only property.
     
     // error, can not be unintalized
     for(const c9; c9 < 1;) { }

tests/baselines/reference/constEnumBadPropertyNames.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/compiler/constEnumBadPropertyNames.ts(2,11): error TS2479: Property 'B' does not exist on 'const' enum 'E'.
+tests/cases/compiler/constEnumBadPropertyNames.ts(2,11): error TS2339: Property 'B' does not exist on type 'typeof E'.
 
 
 ==== tests/cases/compiler/constEnumBadPropertyNames.ts (1 errors) ====
     const enum E { A }
     var x = E["B"]
               ~~~
-!!! error TS2479: Property 'B' does not exist on 'const' enum 'E'.
+!!! error TS2339: Property 'B' does not exist on type 'typeof E'.

tests/baselines/reference/constEnumPropertyAccess2.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(14,9): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(15,12): error TS2476: A const enum member can only be accessed using a string literal.
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(17,1): error TS2322: Type '"string"' is not assignable to type 'G'.
-tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(19,3): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts (4 errors) ====
@@ -30,6 +30,6 @@ tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(19,1): error TS24
 !!! error TS2322: Type '"string"' is not assignable to type 'G'.
     function foo(x: G) { }
     G.B = 3;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     

tests/baselines/reference/constIndexedAccess.types

@@ -76,16 +76,16 @@ enum numbersNotConst {
 }
 
 let s3 = test[numbersNotConst.zero];
->s3 : any
->test[numbersNotConst.zero] : any
+>s3 : string
+>test[numbersNotConst.zero] : string
 >test : indexAccess
 >numbersNotConst.zero : numbersNotConst.zero
 >numbersNotConst : typeof numbersNotConst
 >zero : numbersNotConst.zero
 
 let n3 = test[numbersNotConst.one];
->n3 : any
->test[numbersNotConst.one] : any
+>n3 : number
+>test[numbersNotConst.one] : number
 >test : indexAccess
 >numbersNotConst.one : numbersNotConst.one
 >numbersNotConst : typeof numbersNotConst

tests/baselines/reference/constructorWithIncompleteTypeAnnotation.errors.txt

@@ -25,7 +25,7 @@ tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(59,5): error TS1
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(70,13): error TS1109: Expression expected.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(73,37): error TS1127: Invalid character.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(82,13): error TS1109: Expression expected.
-tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(90,23): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(90,23): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(91,13): error TS1109: Expression expected.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(106,29): error TS1109: Expression expected.
 tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(107,13): error TS1109: Expression expected.
@@ -236,7 +236,7 @@ tests/cases/compiler/constructorWithIncompleteTypeAnnotation.ts(262,1): error TS
                 //
                 var any = 0 ^= 
                           ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
                 var bool = 0;
                 ~~~
 !!! error TS1109: Expression expected.

tests/baselines/reference/contextualTypingOfTooShortOverloads.js

@@ -0,0 +1,59 @@
+//// [contextualTypingOfTooShortOverloads.ts]
+// small repro from #11875
+var use: Overload;
+use((req, res) => {});
+
+interface Overload {
+    (handler1: (req1: string) => void): void;
+    (handler2: (req2: number, res2: number) => void): void;
+}
+// larger repro from #11875
+let app: MyApp;
+app.use((err: any, req, res, next) => { return; });
+
+
+interface MyApp {
+    use: IRouterHandler<this> & IRouterMatcher<this>;
+}
+
+interface IRouterHandler<T> {
+    (...handlers: RequestHandler[]): T;
+    (...handlers: RequestHandlerParams[]): T;
+}
+
+interface IRouterMatcher<T> {
+    (path: PathParams, ...handlers: RequestHandler[]): T;
+    (path: PathParams, ...handlers: RequestHandlerParams[]): T;
+}
+
+type PathParams = string | RegExp | (string | RegExp)[];
+type RequestHandlerParams = RequestHandler | ErrorRequestHandler | (RequestHandler | ErrorRequestHandler)[];
+
+interface RequestHandler {
+    (req: Request, res: Response, next: NextFunction): any;
+}
+
+interface ErrorRequestHandler {
+    (err: any, req: Request, res: Response, next: NextFunction): any;
+}
+
+interface Request {
+    method: string;
+}
+
+interface Response {
+    statusCode: number;
+}
+
+interface NextFunction {
+    (err?: any): void;
+}
+
+
+//// [contextualTypingOfTooShortOverloads.js]
+// small repro from #11875
+var use;
+use(function (req, res) { });
+// larger repro from #11875
+var app;
+app.use(function (err, req, res, next) { return; });

tests/baselines/reference/contextualTypingOfTooShortOverloads.symbols

@@ -0,0 +1,139 @@
+=== tests/cases/compiler/contextualTypingOfTooShortOverloads.ts ===
+// small repro from #11875
+var use: Overload;
+>use : Symbol(use, Decl(contextualTypingOfTooShortOverloads.ts, 1, 3))
+>Overload : Symbol(Overload, Decl(contextualTypingOfTooShortOverloads.ts, 2, 22))
+
+use((req, res) => {});
+>use : Symbol(use, Decl(contextualTypingOfTooShortOverloads.ts, 1, 3))
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 2, 5))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 2, 9))
+
+interface Overload {
+>Overload : Symbol(Overload, Decl(contextualTypingOfTooShortOverloads.ts, 2, 22))
+
+    (handler1: (req1: string) => void): void;
+>handler1 : Symbol(handler1, Decl(contextualTypingOfTooShortOverloads.ts, 5, 5))
+>req1 : Symbol(req1, Decl(contextualTypingOfTooShortOverloads.ts, 5, 16))
+
+    (handler2: (req2: number, res2: number) => void): void;
+>handler2 : Symbol(handler2, Decl(contextualTypingOfTooShortOverloads.ts, 6, 5))
+>req2 : Symbol(req2, Decl(contextualTypingOfTooShortOverloads.ts, 6, 16))
+>res2 : Symbol(res2, Decl(contextualTypingOfTooShortOverloads.ts, 6, 29))
+}
+// larger repro from #11875
+let app: MyApp;
+>app : Symbol(app, Decl(contextualTypingOfTooShortOverloads.ts, 9, 3))
+>MyApp : Symbol(MyApp, Decl(contextualTypingOfTooShortOverloads.ts, 10, 51))
+
+app.use((err: any, req, res, next) => { return; });
+>app.use : Symbol(MyApp.use, Decl(contextualTypingOfTooShortOverloads.ts, 13, 17))
+>app : Symbol(app, Decl(contextualTypingOfTooShortOverloads.ts, 9, 3))
+>use : Symbol(MyApp.use, Decl(contextualTypingOfTooShortOverloads.ts, 13, 17))
+>err : Symbol(err, Decl(contextualTypingOfTooShortOverloads.ts, 10, 9))
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 10, 18))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 10, 23))
+>next : Symbol(next, Decl(contextualTypingOfTooShortOverloads.ts, 10, 28))
+
+
+interface MyApp {
+>MyApp : Symbol(MyApp, Decl(contextualTypingOfTooShortOverloads.ts, 10, 51))
+
+    use: IRouterHandler<this> & IRouterMatcher<this>;
+>use : Symbol(MyApp.use, Decl(contextualTypingOfTooShortOverloads.ts, 13, 17))
+>IRouterHandler : Symbol(IRouterHandler, Decl(contextualTypingOfTooShortOverloads.ts, 15, 1))
+>IRouterMatcher : Symbol(IRouterMatcher, Decl(contextualTypingOfTooShortOverloads.ts, 20, 1))
+}
+
+interface IRouterHandler<T> {
+>IRouterHandler : Symbol(IRouterHandler, Decl(contextualTypingOfTooShortOverloads.ts, 15, 1))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 17, 25))
+
+    (...handlers: RequestHandler[]): T;
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 18, 5))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 17, 25))
+
+    (...handlers: RequestHandlerParams[]): T;
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 19, 5))
+>RequestHandlerParams : Symbol(RequestHandlerParams, Decl(contextualTypingOfTooShortOverloads.ts, 27, 56))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 17, 25))
+}
+
+interface IRouterMatcher<T> {
+>IRouterMatcher : Symbol(IRouterMatcher, Decl(contextualTypingOfTooShortOverloads.ts, 20, 1))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 22, 25))
+
+    (path: PathParams, ...handlers: RequestHandler[]): T;
+>path : Symbol(path, Decl(contextualTypingOfTooShortOverloads.ts, 23, 5))
+>PathParams : Symbol(PathParams, Decl(contextualTypingOfTooShortOverloads.ts, 25, 1))
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 23, 22))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 22, 25))
+
+    (path: PathParams, ...handlers: RequestHandlerParams[]): T;
+>path : Symbol(path, Decl(contextualTypingOfTooShortOverloads.ts, 24, 5))
+>PathParams : Symbol(PathParams, Decl(contextualTypingOfTooShortOverloads.ts, 25, 1))
+>handlers : Symbol(handlers, Decl(contextualTypingOfTooShortOverloads.ts, 24, 22))
+>RequestHandlerParams : Symbol(RequestHandlerParams, Decl(contextualTypingOfTooShortOverloads.ts, 27, 56))
+>T : Symbol(T, Decl(contextualTypingOfTooShortOverloads.ts, 22, 25))
+}
+
+type PathParams = string | RegExp | (string | RegExp)[];
+>PathParams : Symbol(PathParams, Decl(contextualTypingOfTooShortOverloads.ts, 25, 1))
+>RegExp : Symbol(RegExp, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>RegExp : Symbol(RegExp, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+type RequestHandlerParams = RequestHandler | ErrorRequestHandler | (RequestHandler | ErrorRequestHandler)[];
+>RequestHandlerParams : Symbol(RequestHandlerParams, Decl(contextualTypingOfTooShortOverloads.ts, 27, 56))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>ErrorRequestHandler : Symbol(ErrorRequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 32, 1))
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+>ErrorRequestHandler : Symbol(ErrorRequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 32, 1))
+
+interface RequestHandler {
+>RequestHandler : Symbol(RequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 28, 108))
+
+    (req: Request, res: Response, next: NextFunction): any;
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 31, 5))
+>Request : Symbol(Request, Decl(contextualTypingOfTooShortOverloads.ts, 36, 1))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 31, 18))
+>Response : Symbol(Response, Decl(contextualTypingOfTooShortOverloads.ts, 40, 1))
+>next : Symbol(next, Decl(contextualTypingOfTooShortOverloads.ts, 31, 33))
+>NextFunction : Symbol(NextFunction, Decl(contextualTypingOfTooShortOverloads.ts, 44, 1))
+}
+
+interface ErrorRequestHandler {
+>ErrorRequestHandler : Symbol(ErrorRequestHandler, Decl(contextualTypingOfTooShortOverloads.ts, 32, 1))
+
+    (err: any, req: Request, res: Response, next: NextFunction): any;
+>err : Symbol(err, Decl(contextualTypingOfTooShortOverloads.ts, 35, 5))
+>req : Symbol(req, Decl(contextualTypingOfTooShortOverloads.ts, 35, 14))
+>Request : Symbol(Request, Decl(contextualTypingOfTooShortOverloads.ts, 36, 1))
+>res : Symbol(res, Decl(contextualTypingOfTooShortOverloads.ts, 35, 28))
+>Response : Symbol(Response, Decl(contextualTypingOfTooShortOverloads.ts, 40, 1))
+>next : Symbol(next, Decl(contextualTypingOfTooShortOverloads.ts, 35, 43))
+>NextFunction : Symbol(NextFunction, Decl(contextualTypingOfTooShortOverloads.ts, 44, 1))
+}
+
+interface Request {
+>Request : Symbol(Request, Decl(contextualTypingOfTooShortOverloads.ts, 36, 1))
+
+    method: string;
+>method : Symbol(Request.method, Decl(contextualTypingOfTooShortOverloads.ts, 38, 19))
+}
+
+interface Response {
+>Response : Symbol(Response, Decl(contextualTypingOfTooShortOverloads.ts, 40, 1))
+
+    statusCode: number;
+>statusCode : Symbol(Response.statusCode, Decl(contextualTypingOfTooShortOverloads.ts, 42, 20))
+}
+
+interface NextFunction {
+>NextFunction : Symbol(NextFunction, Decl(contextualTypingOfTooShortOverloads.ts, 44, 1))
+
+    (err?: any): void;
+>err : Symbol(err, Decl(contextualTypingOfTooShortOverloads.ts, 47, 5))
+}
+

tests/baselines/reference/contextualTypingOfTooShortOverloads.types

@@ -0,0 +1,143 @@
+=== tests/cases/compiler/contextualTypingOfTooShortOverloads.ts ===
+// small repro from #11875
+var use: Overload;
+>use : Overload
+>Overload : Overload
+
+use((req, res) => {});
+>use((req, res) => {}) : void
+>use : Overload
+>(req, res) => {} : (req: any, res: any) => void
+>req : any
+>res : any
+
+interface Overload {
+>Overload : Overload
+
+    (handler1: (req1: string) => void): void;
+>handler1 : (req1: string) => void
+>req1 : string
+
+    (handler2: (req2: number, res2: number) => void): void;
+>handler2 : (req2: number, res2: number) => void
+>req2 : number
+>res2 : number
+}
+// larger repro from #11875
+let app: MyApp;
+>app : MyApp
+>MyApp : MyApp
+
+app.use((err: any, req, res, next) => { return; });
+>app.use((err: any, req, res, next) => { return; }) : MyApp
+>app.use : IRouterHandler<MyApp> & IRouterMatcher<MyApp>
+>app : MyApp
+>use : IRouterHandler<MyApp> & IRouterMatcher<MyApp>
+>(err: any, req, res, next) => { return; } : (err: any, req: any, res: any, next: any) => void
+>err : any
+>req : any
+>res : any
+>next : any
+
+
+interface MyApp {
+>MyApp : MyApp
+
+    use: IRouterHandler<this> & IRouterMatcher<this>;
+>use : IRouterHandler<this> & IRouterMatcher<this>
+>IRouterHandler : IRouterHandler<T>
+>IRouterMatcher : IRouterMatcher<T>
+}
+
+interface IRouterHandler<T> {
+>IRouterHandler : IRouterHandler<T>
+>T : T
+
+    (...handlers: RequestHandler[]): T;
+>handlers : RequestHandler[]
+>RequestHandler : RequestHandler
+>T : T
+
+    (...handlers: RequestHandlerParams[]): T;
+>handlers : RequestHandlerParams[]
+>RequestHandlerParams : RequestHandlerParams
+>T : T
+}
+
+interface IRouterMatcher<T> {
+>IRouterMatcher : IRouterMatcher<T>
+>T : T
+
+    (path: PathParams, ...handlers: RequestHandler[]): T;
+>path : PathParams
+>PathParams : PathParams
+>handlers : RequestHandler[]
+>RequestHandler : RequestHandler
+>T : T
+
+    (path: PathParams, ...handlers: RequestHandlerParams[]): T;
+>path : PathParams
+>PathParams : PathParams
+>handlers : RequestHandlerParams[]
+>RequestHandlerParams : RequestHandlerParams
+>T : T
+}
+
+type PathParams = string | RegExp | (string | RegExp)[];
+>PathParams : PathParams
+>RegExp : RegExp
+>RegExp : RegExp
+
+type RequestHandlerParams = RequestHandler | ErrorRequestHandler | (RequestHandler | ErrorRequestHandler)[];
+>RequestHandlerParams : RequestHandlerParams
+>RequestHandler : RequestHandler
+>ErrorRequestHandler : ErrorRequestHandler
+>RequestHandler : RequestHandler
+>ErrorRequestHandler : ErrorRequestHandler
+
+interface RequestHandler {
+>RequestHandler : RequestHandler
+
+    (req: Request, res: Response, next: NextFunction): any;
+>req : Request
+>Request : Request
+>res : Response
+>Response : Response
+>next : NextFunction
+>NextFunction : NextFunction
+}
+
+interface ErrorRequestHandler {
+>ErrorRequestHandler : ErrorRequestHandler
+
+    (err: any, req: Request, res: Response, next: NextFunction): any;
+>err : any
+>req : Request
+>Request : Request
+>res : Response
+>Response : Response
+>next : NextFunction
+>NextFunction : NextFunction
+}
+
+interface Request {
+>Request : Request
+
+    method: string;
+>method : string
+}
+
+interface Response {
+>Response : Response
+
+    statusCode: number;
+>statusCode : number
+}
+
+interface NextFunction {
+>NextFunction : NextFunction
+
+    (err?: any): void;
+>err : any
+}
+

tests/baselines/reference/decrementAndIncrementOperators.errors.txt

@@ -1,16 +1,16 @@
-tests/cases/compiler/decrementAndIncrementOperators.ts(4,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(6,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(7,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(9,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(10,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(12,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(13,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(15,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(16,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(18,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(19,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(21,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/compiler/decrementAndIncrementOperators.ts(22,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/compiler/decrementAndIncrementOperators.ts(4,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(6,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(7,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(9,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(10,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(12,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(13,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(15,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(16,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(18,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(19,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(21,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/compiler/decrementAndIncrementOperators.ts(22,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 
 
 ==== tests/cases/compiler/decrementAndIncrementOperators.ts (13 errors) ====
@@ -19,49 +19,49 @@ tests/cases/compiler/decrementAndIncrementOperators.ts(22,3): error TS2357: The
     // errors
     1 ++;
     ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     (1)++;
     ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     (1)--;
     ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     ++(1);
       ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --(1);
       ~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     (1 + 2)++;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     (1 + 2)--;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     ++(1 + 2);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --(1 + 2);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     (x + x)++;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     (x + x)--;
     ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     ++(x + x);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --(x + x);
       ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     //OK
     x++;

tests/baselines/reference/decrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt

@@ -1,36 +1,36 @@
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(27,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(28,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(30,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(33,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(34,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(37,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(38,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2539: Cannot assign to 'undefined' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(41,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(42,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2539: Cannot assign to 'undefined' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,27): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(51,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(52,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,25): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(59,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithAnyOtherTypeInvalidOperations.ts(60,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -79,10 +79,10 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber2 = --A;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber3 = --M;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber4 = --obj;
                             ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -95,10 +95,10 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber7 = A--;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber8 = M--;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber9 = obj--;
                           ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -115,7 +115,7 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber13 = --undefined;
                              ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     var ResultIsNumber14 = null--;
                            ~~~~
@@ -125,28 +125,28 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber16 = undefined--;
                            ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     // any type expressions
     var ResultIsNumber17 = --foo();
                              ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber18 = --A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber19 = --(null + undefined);
                              ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber20 = --(null + null);
                              ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber21 = --(undefined + undefined);
                              ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber22 = --obj1.x;
@@ -158,23 +158,23 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     
     var ResultIsNumber24 = foo()--;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber25 = A.foo()--;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber26 = (null + undefined)--;
                            ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber27 = (null + null)--;
                            ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber28 = (undefined + undefined)--;
                            ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber29 = obj1.x--;

tests/baselines/reference/decrementOperatorWithEnumType.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(6,25): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(7,23): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(10,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(6,31): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(7,29): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(10,9): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,1): error TS2542: Index signature in type 'typeof ENUM1' only permits reading.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumType.ts(12,7): error TS2304: Cannot find name 'A'.
 
 
@@ -12,19 +12,19 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     
     // expression
     var ResultIsNumber1 = --ENUM1["A"];
-                            ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                  ~~~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     var ResultIsNumber2 = ENUM1.A--;
-                          ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     // miss assignment operator
     --ENUM1["A"];
-      ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+            ~~~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     ENUM1[A]--;
     ~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2542: Index signature in type 'typeof ENUM1' only permits reading.
           ~
 !!! error TS2304: Cannot find name 'A'.

tests/baselines/reference/decrementOperatorWithEnumTypeInvalidOperations.errors.txt

@@ -1,15 +1,15 @@
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(14,43): error TS2339: Property 'B' does not exist on type 'typeof ENUM'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,23): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,23): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(15,29): error TS2339: Property 'A' does not exist on type 'typeof ENUM'.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithEnumTypeInvalidOperations.ts (12 errors) ====
@@ -21,41 +21,41 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // enum type var
     var ResultIsNumber1 = --ENUM;
                             ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber2 = --ENUM1;
                             ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     var ResultIsNumber3 = ENUM--;
                           ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber4 = ENUM1--;
                           ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     // enum type expressions
     var ResultIsNumber5 = --(ENUM["A"] + ENUM.B);
                             ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                                               ~
 !!! error TS2339: Property 'B' does not exist on type 'typeof ENUM'.
     var ResultIsNumber6 = (ENUM.A + ENUM["B"])--;
                           ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                                 ~
 !!! error TS2339: Property 'A' does not exist on type 'typeof ENUM'.
     
     // miss assignment operator
     --ENUM;
       ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     --ENUM1;
       ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     ENUM--;
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     ENUM1--;
     ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.

tests/baselines/reference/decrementOperatorWithNumberTypeInvalidOperations.errors.txt

@@ -1,23 +1,23 @@
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(18,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(19,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(23,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(27,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(28,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(41,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(45,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOperatorWithNumberTypeInvalidOperations.ts (20 errors) ====
@@ -48,7 +48,7 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // number type literal
     var ResultIsNumber3 = --1;
                             ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber4 = --{ x: 1, y: 2};
                             ~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -58,7 +58,7 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     
     var ResultIsNumber6 = 1--;
                           ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber7 = { x: 1, y: 2 }--;
                           ~~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -69,41 +69,41 @@ tests/cases/conformance/expressions/unaryOperators/decrementOperator/decrementOp
     // number type expressions
     var ResultIsNumber9 = --foo();
                             ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber10 = --A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber11 = --(NUMBER + NUMBER);
                              ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     var ResultIsNumber12 = foo()--;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber13 = A.foo()--;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber14 = (NUMBER + NUMBER)--;
                            ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     // miss assignment operator
     --1;
       ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     --NUMBER1;
       ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     --foo();
       ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     1--;
     ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     NUMBER1--;
     ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     foo()--;
     ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.

tests/baselines/reference/doWhileUnreachableCode.js

@@ -0,0 +1,26 @@
+//// [doWhileUnreachableCode.ts]
+function test() {
+    let foo = 0;
+    testLoop: do {
+        foo++;
+        continue testLoop;
+    } while (function() {
+        var x = 1;
+        return false;
+    }());
+
+    return foo;
+}
+
+//// [doWhileUnreachableCode.js]
+function test() {
+    var foo = 0;
+    testLoop: do {
+        foo++;
+        continue testLoop;
+    } while (function () {
+        var x = 1;
+        return false;
+    }());
+    return foo;
+}

tests/baselines/reference/doWhileUnreachableCode.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/doWhileUnreachableCode.ts ===
+function test() {
+>test : Symbol(test, Decl(doWhileUnreachableCode.ts, 0, 0))
+
+    let foo = 0;
+>foo : Symbol(foo, Decl(doWhileUnreachableCode.ts, 1, 7))
+
+    testLoop: do {
+        foo++;
+>foo : Symbol(foo, Decl(doWhileUnreachableCode.ts, 1, 7))
+
+        continue testLoop;
+    } while (function() {
+        var x = 1;
+>x : Symbol(x, Decl(doWhileUnreachableCode.ts, 6, 11))
+
+        return false;
+    }());
+
+    return foo;
+>foo : Symbol(foo, Decl(doWhileUnreachableCode.ts, 1, 7))
+}

tests/baselines/reference/doWhileUnreachableCode.types

@@ -0,0 +1,34 @@
+=== tests/cases/compiler/doWhileUnreachableCode.ts ===
+function test() {
+>test : () => number
+
+    let foo = 0;
+>foo : number
+>0 : 0
+
+    testLoop: do {
+>testLoop : any
+
+        foo++;
+>foo++ : number
+>foo : number
+
+        continue testLoop;
+>testLoop : any
+
+    } while (function() {
+>function() {        var x = 1;        return false;    }() : boolean
+>function() {        var x = 1;        return false;    } : () => boolean
+
+        var x = 1;
+>x : number
+>1 : 1
+
+        return false;
+>false : false
+
+    }());
+
+    return foo;
+>foo : number
+}

tests/baselines/reference/enumLiteralTypes1.types

@@ -209,11 +209,11 @@ function f4(a: Choice.Yes, b: YesNo) {
 
     a++;
 >a++ : number
->a : Choice.Yes
+>a : Choice
 
     b++;
 >b++ : number
->b : YesNo
+>b : Choice
 }
 
 declare function g(x: Choice.Yes): string;

tests/baselines/reference/enumLiteralTypes2.types

@@ -210,7 +210,7 @@ function f4(a: Choice.Yes, b: UnknownYesNo) {
 
     a++;
 >a++ : number
->a : Choice.Yes
+>a : Choice
 
     b++;
 >b++ : number

tests/baselines/reference/externalModuleImmutableBindings.errors.txt

@@ -1,23 +1,23 @@
-tests/cases/compiler/f2.ts(7,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(7,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(8,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(9,7): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
-tests/cases/compiler/f2.ts(12,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(13,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(18,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(12,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(13,7): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(17,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(18,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(19,8): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
-tests/cases/compiler/f2.ts(22,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(23,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(27,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(28,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(29,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(30,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(22,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(23,8): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(27,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(28,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(29,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(30,12): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(31,12): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(32,12): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
-tests/cases/compiler/f2.ts(36,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(37,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
-tests/cases/compiler/f2.ts(38,6): error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
-tests/cases/compiler/f2.ts(39,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/compiler/f2.ts(36,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(37,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(38,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/compiler/f2.ts(39,13): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
 tests/cases/compiler/f2.ts(40,13): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
 
@@ -33,57 +33,57 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     var n = 'baz';
     
     stuff.x = 0;
-    ~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['x'] = 1;
-    ~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+          ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff.blah = 2;
           ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
     stuff[n] = 3;
     
     stuff.x++;
-    ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['x']++;
-    ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     stuff['blah']++;
     stuff[n]++;
     
     (stuff.x) = 0;
-    ~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+           ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['x']) = 1;
-    ~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+           ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff.blah) = 2;
            ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
     (stuff[n]) = 3;
     
     (stuff.x)++;
-    ~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+           ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['x'])++;
-    ~~~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+           ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     (stuff['blah'])++;
     (stuff[n])++;
     
     for (stuff.x in []) {}
-         ~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+               ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff.x of []) {}
-         ~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+               ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff['x'] in []) {}
-         ~~~~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+               ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff['x'] of []) {}
-         ~~~~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+               ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for (stuff.blah in []) {}
                ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.
@@ -94,17 +94,17 @@ tests/cases/compiler/f2.ts(41,13): error TS2339: Property 'blah' does not exist
     for (stuff[n] of []) {}
     
     for ((stuff.x) in []) {}
-         ~~~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+                ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff.x) of []) {}
-         ~~~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+                ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff['x']) in []) {}
-         ~~~~~~~~~~~~
-!!! error TS2405: The left-hand side of a 'for...in' statement must be of type 'string' or 'any'.
+                ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff['x']) of []) {}
-         ~~~~~~~~~~~~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+                ~~~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     for ((stuff.blah) in []) {}
                 ~~~~
 !!! error TS2339: Property 'blah' does not exist on type 'typeof "tests/cases/compiler/f1"'.

tests/baselines/reference/for-inStatementsArrayErrors.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(5,14): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(5,16): error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(6,16): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(7,9): error TS2365: Operator '===' cannot be applied to types 'string' and 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.ts(9,16): error TS2339: Property 'unknownProperty' does not exist on type 'string'.
@@ -12,7 +12,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsArrayErrors.
     
     for (let x in a) {
         let a1 = a[x + 1];
-                 ~~~~~~~~
+                   ~~~~~
 !!! error TS7015: Element implicitly has an 'any' type because index expression is not of type 'number'.
         let a2 = a[x - 1];
                    ~

tests/baselines/reference/for-of2.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/conformance/es6/for-ofStatements/for-of2.ts(1,7): error TS1155: 'const' declarations must be initialized
-tests/cases/conformance/es6/for-ofStatements/for-of2.ts(2,6): error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+tests/cases/conformance/es6/for-ofStatements/for-of2.ts(2,6): error TS2540: Cannot assign to 'v' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/es6/for-ofStatements/for-of2.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/conformance/es6/for-ofStatements/for-of2.ts(2,6): error TS2485: The
 !!! error TS1155: 'const' declarations must be initialized
     for (v of []) { }
          ~
-!!! error TS2485: The left-hand side of a 'for...of' statement cannot be a constant or a read-only property.
+!!! error TS2540: Cannot assign to 'v' because it is a constant or a read-only property.

tests/baselines/reference/for-of3.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/conformance/es6/for-ofStatements/for-of3.ts(2,6): error TS2487: Invalid left-hand side in 'for...of' statement.
+tests/cases/conformance/es6/for-ofStatements/for-of3.ts(2,6): error TS2487: The left-hand side of a 'for...of' statement must be a variable or a property access.
 
 
 ==== tests/cases/conformance/es6/for-ofStatements/for-of3.ts (1 errors) ====
     var v: any;
     for (v++ of []) { }
          ~~~
-!!! error TS2487: Invalid left-hand side in 'for...of' statement.
+!!! error TS2487: The left-hand side of a 'for...of' statement must be a variable or a property access.

tests/baselines/reference/importsImplicitlyReadonly.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/externalModules/b.ts(6,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/externalModules/b.ts(7,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/externalModules/b.ts(8,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/externalModules/b.ts(9,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/externalModules/b.ts(6,1): error TS2539: Cannot assign to 'x' because it is not a variable.
+tests/cases/conformance/externalModules/b.ts(7,1): error TS2539: Cannot assign to 'y' because it is not a variable.
+tests/cases/conformance/externalModules/b.ts(8,4): error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
+tests/cases/conformance/externalModules/b.ts(9,4): error TS2540: Cannot assign to 'y' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/externalModules/b.ts (4 errors) ====
@@ -12,16 +12,16 @@ tests/cases/conformance/externalModules/b.ts(9,1): error TS2450: Left-hand side
     
     x = 1;     // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'x' because it is not a variable.
     y = 1;     // Error
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'y' because it is not a variable.
     a1.x = 1;  // Error
-    ~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+       ~
+!!! error TS2540: Cannot assign to 'x' because it is a constant or a read-only property.
     a1.y = 1;  // Error
-    ~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+       ~
+!!! error TS2540: Cannot assign to 'y' because it is a constant or a read-only property.
     a2.x = 1;
     a2.y = 1;
     a3.x = 1;

tests/baselines/reference/incrementOperatorWithAnyOtherTypeInvalidOperations.errors.txt

@@ -1,36 +1,36 @@
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(25,25): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(26,25): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(27,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(28,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(30,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(31,23): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(32,23): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(33,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(34,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(37,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(38,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(39,26): error TS2539: Cannot assign to 'undefined' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(41,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(42,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(43,24): error TS2539: Cannot assign to 'undefined' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(46,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(47,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(48,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(49,27): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(50,27): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(51,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(52,26): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(54,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(55,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(56,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(57,25): error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(58,25): error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(59,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithAnyOtherTypeInvalidOperations.ts(60,24): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -74,10 +74,10 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber2 = ++A;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber3 = ++M;
                             ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber4 = ++obj;
                             ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -90,10 +90,10 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber7 = A++;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'A' because it is not a variable.
     var ResultIsNumber8 = M++;
                           ~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     var ResultIsNumber9 = obj++;
                           ~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -110,7 +110,7 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber13 = ++undefined;
                              ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     var ResultIsNumber14 = null++;
                            ~~~~
@@ -120,28 +120,28 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     var ResultIsNumber16 = undefined++;
                            ~~~~~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'undefined' because it is not a variable.
     
     // any type expressions
     var ResultIsNumber17 = ++foo();
                              ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber18 = ++A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber19 = ++(null + undefined);
                              ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber20 = ++(null + null);
                              ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber21 = ++(undefined + undefined);
                              ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                               ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber22 = ++obj1.x;
@@ -153,23 +153,23 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     
     var ResultIsNumber24 = foo()++;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber25 = A.foo()++;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber26 = (null + undefined)++;
                            ~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber27 = (null + null)++;
                            ~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'null' and 'null'.
     var ResultIsNumber28 = (undefined + undefined)++;
                            ~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
                             ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2365: Operator '+' cannot be applied to types 'undefined' and 'undefined'.
     var ResultIsNumber29 = obj1.x++;

tests/baselines/reference/incrementOperatorWithEnumType.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(6,25): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(7,23): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(10,3): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(12,1): error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(6,31): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(7,29): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(10,9): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts(12,7): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumType.ts (4 errors) ====
@@ -11,17 +11,17 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     
     // expression
     var ResultIsNumber1 = ++ENUM1["B"];
-                            ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                  ~~~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     var ResultIsNumber2 = ENUM1.B++;
-                          ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+                                ~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     
     // miss assignment operator
     ++ENUM1["B"];
-      ~~~~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+            ~~~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
     
     ENUM1.B++;
-    ~~~~~~~
-!!! error TS2449: The operand of an increment or decrement operator cannot be a constant or a read-only property.
+          ~
+!!! error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.

tests/baselines/reference/incrementOperatorWithEnumTypeInvalidOperations.errors.txt

@@ -1,13 +1,13 @@
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(7,25): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(8,25): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(10,23): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(11,23): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(14,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(15,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(18,3): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(19,3): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(21,1): error TS2539: Cannot assign to 'ENUM' because it is not a variable.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts(22,1): error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithEnumTypeInvalidOperations.ts (10 errors) ====
@@ -19,17 +19,17 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // enum type var
     var ResultIsNumber1 = ++ENUM;
                             ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber2 = ++ENUM1;
                             ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     var ResultIsNumber3 = ENUM++;
                           ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     var ResultIsNumber4 = ENUM1++;
                           ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     // enum type expressions
     var ResultIsNumber5 = ++(ENUM[1] + ENUM[2]);
@@ -42,14 +42,14 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // miss assignment operator
     ++ENUM;
       ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     ++ENUM1;
       ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.
     
     ENUM++;
     ~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM' because it is not a variable.
     ENUM1++;
     ~~~~~
-!!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
+!!! error TS2539: Cannot assign to 'ENUM1' because it is not a variable.

tests/baselines/reference/incrementOperatorWithNumberTypeInvalidOperations.errors.txt

@@ -1,23 +1,23 @@
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(18,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(19,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(22,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(23,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(24,25): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(26,23): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(27,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(28,23): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(31,25): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(32,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(33,26): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(35,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(36,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(37,24): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(40,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(41,3): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(42,3): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(44,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(45,1): error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
-tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts(46,1): error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
 
 
 ==== tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOperatorWithNumberTypeInvalidOperations.ts (20 errors) ====
@@ -48,7 +48,7 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // number type literal
     var ResultIsNumber3 = ++1;
                             ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber4 = ++{ x: 1, y: 2};
                             ~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -58,7 +58,7 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     
     var ResultIsNumber6 = 1++;
                           ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber7 = { x: 1, y: 2 }++;
                           ~~~~~~~~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
@@ -69,41 +69,41 @@ tests/cases/conformance/expressions/unaryOperators/incrementOperator/incrementOp
     // number type expressions
     var ResultIsNumber9 = ++foo();
                             ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber10 = ++A.foo();
                              ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber11 = ++(NUMBER + NUMBER);
                              ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     var ResultIsNumber12 = foo()++;
                            ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber13 = A.foo()++;
                            ~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     var ResultIsNumber14 = (NUMBER + NUMBER)++;
                            ~~~~~~~~~~~~~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     // miss assignment operator
     ++1;
       ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     ++NUMBER1;
       ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     ++foo();
       ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     
     1++;
     ~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.
     NUMBER1++;
     ~~~~~~~
 !!! error TS2356: An arithmetic operand must be of type 'any', 'number' or an enum type.
     foo()++;
     ~~~~~
-!!! error TS2357: The operand of an increment or decrement operator must be a variable, property or indexer.
+!!! error TS2357: The operand of an increment or decrement operator must be a variable or a property access.

tests/baselines/reference/indexTypeCheck.errors.txt

@@ -5,7 +5,7 @@ tests/cases/compiler/indexTypeCheck.ts(22,2): error TS2413: Numeric index type '
 tests/cases/compiler/indexTypeCheck.ts(27,2): error TS2413: Numeric index type 'number' is not assignable to string index type 'string'.
 tests/cases/compiler/indexTypeCheck.ts(32,3): error TS1096: An index signature must have exactly one parameter.
 tests/cases/compiler/indexTypeCheck.ts(36,3): error TS1023: An index signature parameter type must be 'string' or 'number'.
-tests/cases/compiler/indexTypeCheck.ts(51,1): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexTypeCheck.ts(51,8): error TS2538: Type 'Blue' cannot be used as an index type.
 
 
 ==== tests/cases/compiler/indexTypeCheck.ts (8 errors) ====
@@ -74,8 +74,8 @@ tests/cases/compiler/indexTypeCheck.ts(51,1): error TS2342: An index expression
     s[<any>{}]; // ok
     
     yellow[blue]; // error
-    ~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+           ~~~~
+!!! error TS2538: Type 'Blue' cannot be used as an index type.
     
     var x:number[];
     x[0];

tests/baselines/reference/indexWithUndefinedAndNull.errors.txt

@@ -0,0 +1,28 @@
+tests/cases/compiler/indexWithUndefinedAndNull.ts(9,21): error TS2538: Type 'undefined' cannot be used as an index type.
+tests/cases/compiler/indexWithUndefinedAndNull.ts(10,9): error TS2538: Type 'null' cannot be used as an index type.
+tests/cases/compiler/indexWithUndefinedAndNull.ts(11,21): error TS2538: Type 'undefined' cannot be used as an index type.
+tests/cases/compiler/indexWithUndefinedAndNull.ts(12,9): error TS2538: Type 'null' cannot be used as an index type.
+
+
+==== tests/cases/compiler/indexWithUndefinedAndNull.ts (4 errors) ====
+    interface N {
+        [n: number]: string;
+    }
+    interface S {
+        [s: string]: number;
+    }
+    let n: N;
+    let s: S;
+    let str: string = n[undefined];
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
+    str = n[null];
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
+    let num: number = s[undefined];
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
+    num = s[null];
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
+    

tests/baselines/reference/indexWithUndefinedAndNullStrictNullChecks.errors.txt

@@ -1,11 +1,11 @@
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(9,19): error TS2454: Variable 'n' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(9,19): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(9,21): error TS2538: Type 'undefined' cannot be used as an index type.
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(10,7): error TS2454: Variable 'n' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(10,7): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(10,9): error TS2538: Type 'null' cannot be used as an index type.
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(11,19): error TS2454: Variable 's' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(11,19): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(11,21): error TS2538: Type 'undefined' cannot be used as an index type.
 tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,7): error TS2454: Variable 's' is used before being assigned.
-tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,7): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,9): error TS2538: Type 'null' cannot be used as an index type.
 
 
 ==== tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts (8 errors) ====
@@ -20,21 +20,21 @@ tests/cases/compiler/indexWithUndefinedAndNullStrictNullChecks.ts(12,7): error T
     let str: string = n[undefined];
                       ~
 !!! error TS2454: Variable 'n' is used before being assigned.
-                      ~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
     str = n[null];
           ~
 !!! error TS2454: Variable 'n' is used before being assigned.
-          ~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
     let num: number = s[undefined];
                       ~
 !!! error TS2454: Variable 's' is used before being assigned.
-                      ~~~~~~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+                        ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
     num = s[null];
           ~
 !!! error TS2454: Variable 's' is used before being assigned.
-          ~~~~~~~
-!!! error TS2342: An index expression argument must be of type 'string', 'number', 'symbol', or 'any'.
+            ~~~~
+!!! error TS2538: Type 'null' cannot be used as an index type.
     

tests/baselines/reference/interfaceSpread.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/spread/interfaceSpread.ts(2,5): error TS2697: Interface declaration cannot contain a spread property.
+tests/cases/conformance/types/spread/interfaceSpread.ts(2,5): error TS2698: Interface declaration cannot contain a spread property.
 tests/cases/conformance/types/spread/interfaceSpread.ts(7,10): error TS2339: Property 'jam' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
 tests/cases/conformance/types/spread/interfaceSpread.ts(8,10): error TS2339: Property 'peanutButter' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
 
@@ -7,7 +7,7 @@ tests/cases/conformance/types/spread/interfaceSpread.ts(8,10): error TS2339: Pro
     interface Congealed<T, U> {
         ...T
         ~~~~
-!!! error TS2697: Interface declaration cannot contain a spread property.
+!!! error TS2698: Interface declaration cannot contain a spread property.
         ...U
     }
     

tests/baselines/reference/intersectionTypeReadonly.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(17,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(19,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(21,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(23,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(25,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(17,6): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(19,11): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(21,9): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(23,15): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
+tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(25,15): error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
 
 
 ==== tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts (5 errors) ====
@@ -23,22 +23,22 @@ tests/cases/conformance/types/intersection/intersectionTypeReadonly.ts(25,1): er
     }
     let base: Base;
     base.value = 12 // error, lhs can't be a readonly property
-    ~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+         ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let identical: Base & Identical;
     identical.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+              ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let mutable: Base & Mutable;
     mutable.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+            ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let differentType: Base & DifferentType;
     differentType.value = 12; // error, lhs can't be a readonly property
-    ~~~~~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                  ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     let differentName: Base & DifferentName;
     differentName.value = 12; // error, property 'value' doesn't exist
-    ~~~~~~~~~~~~~~~~~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+                  ~~~~~
+!!! error TS2540: Cannot assign to 'value' because it is a constant or a read-only property.
     

tests/baselines/reference/invalidBooleanAssignments.errors.txt

@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(9,
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(12,5): error TS2322: Type 'true' is not assignable to type 'C'.
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(15,5): error TS2322: Type 'true' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(17,5): error TS2322: Type 'true' is not assignable to type '() => string'.
-tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(21,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(24,5): error TS2322: Type 'boolean' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts (10 errors) ====
@@ -47,7 +47,7 @@ tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26
     module M { export var a = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -56,4 +56,4 @@ tests/cases/conformance/types/primitives/boolean/invalidBooleanAssignments.ts(26
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.

tests/baselines/reference/invalidNumberAssignments.errors.txt

@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(9,5)
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(12,5): error TS2322: Type 'number' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(14,5): error TS2322: Type '1' is not assignable to type '{ baz: string; }'.
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(15,5): error TS2322: Type '1' is not assignable to type '{ 0: number; }'.
-tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(18,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(21,5): error TS2322: Type 'number' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts (10 errors) ====
@@ -44,7 +44,7 @@ tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -53,4 +53,4 @@ tests/cases/conformance/types/primitives/number/invalidNumberAssignments.ts(23,1
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.

tests/baselines/reference/invalidStringAssignments.errors.txt

@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(9,5)
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(12,5): error TS2322: Type 'string' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(14,5): error TS2322: Type '1' is not assignable to type '{ baz: string; }'.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(15,5): error TS2322: Type '1' is not assignable to type '{ 0: number; }'.
-tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(18,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(21,5): error TS2322: Type 'string' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(23,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(23,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(26,5): error TS2322: Type 'string' is not assignable to type 'E'.
 
 
@@ -45,7 +45,7 @@ tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(26,5
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -54,7 +54,7 @@ tests/cases/conformance/types/primitives/string/invalidStringAssignments.ts(26,5
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
     
     enum E { A }
     var j: E = x;

tests/baselines/reference/invalidUndefinedAssignments.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(4,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(5,1): error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(9,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(4,1): error TS2539: Cannot assign to 'E' because it is not a variable.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(5,3): error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(9,1): error TS2539: Cannot assign to 'C' because it is not a variable.
 tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(14,1): error TS2693: 'I' only refers to a type, but is being used as a value here.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(17,1): error TS2364: Invalid left-hand side of assignment expression.
-tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(21,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts(21,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 
 
 ==== tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.ts (6 errors) ====
@@ -12,16 +12,16 @@ tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.t
     enum E { A }
     E = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'E' because it is not a variable.
     E.A = x;
-    ~~~
-!!! error TS2450: Left-hand side of assignment expression cannot be a constant or a read-only property.
+      ~
+!!! error TS2540: Cannot assign to 'A' because it is a constant or a read-only property.
     
     class C { foo: string }
     var f: C;
     C = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'C' because it is not a variable.
     
     interface I { foo: string }
     var g: I;
@@ -33,10 +33,10 @@ tests/cases/conformance/types/primitives/undefined/invalidUndefinedAssignments.t
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) { }
     // BUG 767030
     i = x; 
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.

tests/baselines/reference/invalidVoidAssignments.errors.txt

@@ -5,9 +5,9 @@ tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(9,5): er
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(12,5): error TS2322: Type 'void' is not assignable to type 'I'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(14,5): error TS2322: Type '1' is not assignable to type '{ baz: string; }'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(15,5): error TS2322: Type '1' is not assignable to type '{ 0: number; }'.
-tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(18,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(18,1): error TS2539: Cannot assign to 'M' because it is not a variable.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(21,5): error TS2322: Type 'void' is not assignable to type 'T'.
-tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(23,1): error TS2364: Invalid left-hand side of assignment expression.
+tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(23,1): error TS2539: Cannot assign to 'i' because it is not a variable.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(26,1): error TS2322: Type 'typeof E' is not assignable to type 'void'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(27,1): error TS2322: Type 'E' is not assignable to type 'void'.
 tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(29,1): error TS2322: Type '{ f(): void; }' is not assignable to type 'void'.
@@ -47,7 +47,7 @@ tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(29,1): e
     module M { export var x = 1; }
     M = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'M' because it is not a variable.
     
     function i<T>(a: T) {
         a = x;
@@ -56,7 +56,7 @@ tests/cases/conformance/types/primitives/void/invalidVoidAssignments.ts(29,1): e
     }
     i = x;
     ~
-!!! error TS2364: Invalid left-hand side of assignment expression.
+!!! error TS2539: Cannot assign to 'i' because it is not a variable.
     
     enum E { A }
     x = E;

tests/baselines/reference/keyofAndIndexedAccess.js

@@ -0,0 +1,350 @@
+//// [keyofAndIndexedAccess.ts]
+
+class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+
+class Item {
+    name: string;
+    price: number;
+}
+
+class Options {
+    visible: "yes" | "no";
+}
+
+type Dictionary<T> = { [x: string]: T };
+
+const enum E { A, B, C }
+
+type K00 = keyof any;  // string | number
+type K01 = keyof string;  // number | "toString" | "charAt" | ...
+type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
+type K03 = keyof boolean;  // "valueOf"
+type K04 = keyof void;  // never
+type K05 = keyof undefined;  // never
+type K06 = keyof null;  // never
+type K07 = keyof never;  // never
+
+type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
+type K11 = keyof Shape[];  // number | "length" | "toString" | ...
+type K12 = keyof Dictionary<Shape>;  // string | number
+type K13 = keyof {};  // never
+type K14 = keyof Object;  // "constructor" | "toString" | ...
+type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
+type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
+type K17 = keyof (Shape | Item);  // "name"
+type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
+
+type KeyOf<T> = keyof T;
+
+type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
+type K21 = KeyOf<Dictionary<Shape>>;  // string | number
+
+type NAME = "name";
+type WIDTH_OR_HEIGHT = "width" | "height";
+
+type Q10 = Shape["name"];  // string
+type Q11 = Shape["width" | "height"];  // number
+type Q12 = Shape["name" | "visible"];  // string | boolean
+
+type Q20 = Shape[NAME];  // string
+type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
+
+type Q30 = [string, number][0];  // string
+type Q31 = [string, number][1];  // number
+type Q32 = [string, number][2];  // string | number
+type Q33 = [string, number][E.A];  // string
+type Q34 = [string, number][E.B];  // number
+type Q35 = [string, number][E.C];  // string | number
+type Q36 = [string, number]["0"];  // string
+type Q37 = [string, number]["1"];  // string
+
+type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
+type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
+
+type Q50 = Dictionary<Shape>["howdy"];  // Shape
+type Q51 = Dictionary<Shape>[123];  // Shape
+type Q52 = Dictionary<Shape>[E.B];  // Shape
+
+declare let cond: boolean;
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+    return obj[key];
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+    obj[key] = value;
+}
+
+function f10(shape: Shape) {
+    let name = getProperty(shape, "name");  // string
+    let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
+    let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, cond ? "width" : "height", 10);
+    setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
+}
+
+function f11(a: Shape[]) {
+    let len = getProperty(a, "length");  // number
+    let shape = getProperty(a, 1000);    // Shape
+    setProperty(a, 1000, getProperty(a, 1001));
+}
+
+function f12(t: [Shape, boolean]) {
+    let len = getProperty(t, "length");
+    let s1 = getProperty(t, 0);    // Shape
+    let s2 = getProperty(t, "0");  // Shape
+    let b1 = getProperty(t, 1);    // boolean
+    let b2 = getProperty(t, "1");  // boolean
+    let x1 = getProperty(t, 2);    // Shape | boolean
+}
+
+function f13(foo: any, bar: any) {
+    let x = getProperty(foo, "x");  // any
+    let y = getProperty(foo, 100);  // any
+    let z = getProperty(foo, bar);  // any
+}
+
+class Component<PropType> {
+    props: PropType;
+    getProperty<K extends keyof PropType>(key: K) {
+        return this.props[key];
+    }
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
+        this.props[key] = value;
+    }
+}
+
+function f20(component: Component<Shape>) {
+    let name = component.getProperty("name");  // string
+    let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
+    let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
+    component.setProperty("name", "rectangle");
+    component.setProperty(cond ? "width" : "height", 10)
+    component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
+}
+
+function pluck<T, K extends keyof T>(array: T[], key: K) {
+    return array.map(x => x[key]);
+}
+
+function f30(shapes: Shape[]) {
+    let names = pluck(shapes, "name");    // string[]
+    let widths = pluck(shapes, "width");  // number[]
+    let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
+}
+
+function f31<K extends keyof Shape>(key: K) {
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key];  // Shape[K]
+}
+
+function f32<K extends "width" | "height">(key: K) {
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key];  // Shape[K]
+}
+
+class C {
+    public x: string;
+    protected y: string;
+    private z: string;
+}
+
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c: C) {
+    type X = C["x"];
+    type Y = C["y"];
+    type Z = C["z"];
+    let x: X = c["x"];
+    let y: Y = c["y"];
+    let z: Z = c["z"];
+}
+
+//// [keyofAndIndexedAccess.js]
+var Shape = (function () {
+    function Shape() {
+    }
+    return Shape;
+}());
+var Item = (function () {
+    function Item() {
+    }
+    return Item;
+}());
+var Options = (function () {
+    function Options() {
+    }
+    return Options;
+}());
+function getProperty(obj, key) {
+    return obj[key];
+}
+function setProperty(obj, key, value) {
+    obj[key] = value;
+}
+function f10(shape) {
+    var name = getProperty(shape, "name"); // string
+    var widthOrHeight = getProperty(shape, cond ? "width" : "height"); // number
+    var nameOrVisible = getProperty(shape, cond ? "name" : "visible"); // string | boolean
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, cond ? "width" : "height", 10);
+    setProperty(shape, cond ? "name" : "visible", true); // Technically not safe
+}
+function f11(a) {
+    var len = getProperty(a, "length"); // number
+    var shape = getProperty(a, 1000); // Shape
+    setProperty(a, 1000, getProperty(a, 1001));
+}
+function f12(t) {
+    var len = getProperty(t, "length");
+    var s1 = getProperty(t, 0); // Shape
+    var s2 = getProperty(t, "0"); // Shape
+    var b1 = getProperty(t, 1); // boolean
+    var b2 = getProperty(t, "1"); // boolean
+    var x1 = getProperty(t, 2); // Shape | boolean
+}
+function f13(foo, bar) {
+    var x = getProperty(foo, "x"); // any
+    var y = getProperty(foo, 100); // any
+    var z = getProperty(foo, bar); // any
+}
+var Component = (function () {
+    function Component() {
+    }
+    Component.prototype.getProperty = function (key) {
+        return this.props[key];
+    };
+    Component.prototype.setProperty = function (key, value) {
+        this.props[key] = value;
+    };
+    return Component;
+}());
+function f20(component) {
+    var name = component.getProperty("name"); // string
+    var widthOrHeight = component.getProperty(cond ? "width" : "height"); // number
+    var nameOrVisible = component.getProperty(cond ? "name" : "visible"); // string | boolean
+    component.setProperty("name", "rectangle");
+    component.setProperty(cond ? "width" : "height", 10);
+    component.setProperty(cond ? "name" : "visible", true); // Technically not safe
+}
+function pluck(array, key) {
+    return array.map(function (x) { return x[key]; });
+}
+function f30(shapes) {
+    var names = pluck(shapes, "name"); // string[]
+    var widths = pluck(shapes, "width"); // number[]
+    var nameOrVisibles = pluck(shapes, cond ? "name" : "visible"); // (string | boolean)[]
+}
+function f31(key) {
+    var shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key]; // Shape[K]
+}
+function f32(key) {
+    var shape = { name: "foo", width: 5, height: 10, visible: true };
+    return shape[key]; // Shape[K]
+}
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c) {
+    var x = c["x"];
+    var y = c["y"];
+    var z = c["z"];
+}
+
+
+//// [keyofAndIndexedAccess.d.ts]
+declare class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+declare class Item {
+    name: string;
+    price: number;
+}
+declare class Options {
+    visible: "yes" | "no";
+}
+declare type Dictionary<T> = {
+    [x: string]: T;
+};
+declare const enum E {
+    A = 0,
+    B = 1,
+    C = 2,
+}
+declare type K00 = keyof any;
+declare type K01 = keyof string;
+declare type K02 = keyof number;
+declare type K03 = keyof boolean;
+declare type K04 = keyof void;
+declare type K05 = keyof undefined;
+declare type K06 = keyof null;
+declare type K07 = keyof never;
+declare type K10 = keyof Shape;
+declare type K11 = keyof Shape[];
+declare type K12 = keyof Dictionary<Shape>;
+declare type K13 = keyof {};
+declare type K14 = keyof Object;
+declare type K15 = keyof E;
+declare type K16 = keyof [string, number];
+declare type K17 = keyof (Shape | Item);
+declare type K18 = keyof (Shape & Item);
+declare type KeyOf<T> = keyof T;
+declare type K20 = KeyOf<Shape>;
+declare type K21 = KeyOf<Dictionary<Shape>>;
+declare type NAME = "name";
+declare type WIDTH_OR_HEIGHT = "width" | "height";
+declare type Q10 = Shape["name"];
+declare type Q11 = Shape["width" | "height"];
+declare type Q12 = Shape["name" | "visible"];
+declare type Q20 = Shape[NAME];
+declare type Q21 = Shape[WIDTH_OR_HEIGHT];
+declare type Q30 = [string, number][0];
+declare type Q31 = [string, number][1];
+declare type Q32 = [string, number][2];
+declare type Q33 = [string, number][E.A];
+declare type Q34 = [string, number][E.B];
+declare type Q35 = [string, number][E.C];
+declare type Q36 = [string, number]["0"];
+declare type Q37 = [string, number]["1"];
+declare type Q40 = (Shape | Options)["visible"];
+declare type Q41 = (Shape & Options)["visible"];
+declare type Q50 = Dictionary<Shape>["howdy"];
+declare type Q51 = Dictionary<Shape>[123];
+declare type Q52 = Dictionary<Shape>[E.B];
+declare let cond: boolean;
+declare function getProperty<T, K extends keyof T>(obj: T, key: K): T[K];
+declare function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]): void;
+declare function f10(shape: Shape): void;
+declare function f11(a: Shape[]): void;
+declare function f12(t: [Shape, boolean]): void;
+declare function f13(foo: any, bar: any): void;
+declare class Component<PropType> {
+    props: PropType;
+    getProperty<K extends keyof PropType>(key: K): PropType[K];
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]): void;
+}
+declare function f20(component: Component<Shape>): void;
+declare function pluck<T, K extends keyof T>(array: T[], key: K): T[K][];
+declare function f30(shapes: Shape[]): void;
+declare function f31<K extends keyof Shape>(key: K): Shape[K];
+declare function f32<K extends "width" | "height">(key: K): Shape[K];
+declare class C {
+    x: string;
+    protected y: string;
+    private z;
+}
+declare function f40(c: C): void;

tests/baselines/reference/keyofAndIndexedAccess.symbols

@@ -0,0 +1,577 @@
+=== tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts ===
+
+class Shape {
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    name: string;
+>name : Symbol(Shape.name, Decl(keyofAndIndexedAccess.ts, 1, 13))
+
+    width: number;
+>width : Symbol(Shape.width, Decl(keyofAndIndexedAccess.ts, 2, 17))
+
+    height: number;
+>height : Symbol(Shape.height, Decl(keyofAndIndexedAccess.ts, 3, 18))
+
+    visible: boolean;
+>visible : Symbol(Shape.visible, Decl(keyofAndIndexedAccess.ts, 4, 19))
+}
+
+class Item {
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+
+    name: string;
+>name : Symbol(Item.name, Decl(keyofAndIndexedAccess.ts, 8, 12))
+
+    price: number;
+>price : Symbol(Item.price, Decl(keyofAndIndexedAccess.ts, 9, 17))
+}
+
+class Options {
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+
+    visible: "yes" | "no";
+>visible : Symbol(Options.visible, Decl(keyofAndIndexedAccess.ts, 13, 15))
+}
+
+type Dictionary<T> = { [x: string]: T };
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 17, 16))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 17, 24))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 17, 16))
+
+const enum E { A, B, C }
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 19, 14))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+>C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 19, 20))
+
+type K00 = keyof any;  // string | number
+>K00 : Symbol(K00, Decl(keyofAndIndexedAccess.ts, 19, 24))
+
+type K01 = keyof string;  // number | "toString" | "charAt" | ...
+>K01 : Symbol(K01, Decl(keyofAndIndexedAccess.ts, 21, 21))
+
+type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
+>K02 : Symbol(K02, Decl(keyofAndIndexedAccess.ts, 22, 24))
+
+type K03 = keyof boolean;  // "valueOf"
+>K03 : Symbol(K03, Decl(keyofAndIndexedAccess.ts, 23, 24))
+
+type K04 = keyof void;  // never
+>K04 : Symbol(K04, Decl(keyofAndIndexedAccess.ts, 24, 25))
+
+type K05 = keyof undefined;  // never
+>K05 : Symbol(K05, Decl(keyofAndIndexedAccess.ts, 25, 22))
+
+type K06 = keyof null;  // never
+>K06 : Symbol(K06, Decl(keyofAndIndexedAccess.ts, 26, 27))
+
+type K07 = keyof never;  // never
+>K07 : Symbol(K07, Decl(keyofAndIndexedAccess.ts, 27, 22))
+
+type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
+>K10 : Symbol(K10, Decl(keyofAndIndexedAccess.ts, 28, 23))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K11 = keyof Shape[];  // number | "length" | "toString" | ...
+>K11 : Symbol(K11, Decl(keyofAndIndexedAccess.ts, 30, 23))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K12 = keyof Dictionary<Shape>;  // string | number
+>K12 : Symbol(K12, Decl(keyofAndIndexedAccess.ts, 31, 25))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K13 = keyof {};  // never
+>K13 : Symbol(K13, Decl(keyofAndIndexedAccess.ts, 32, 35))
+
+type K14 = keyof Object;  // "constructor" | "toString" | ...
+>K14 : Symbol(K14, Decl(keyofAndIndexedAccess.ts, 33, 20))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
+>K15 : Symbol(K15, Decl(keyofAndIndexedAccess.ts, 34, 24))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+
+type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
+>K16 : Symbol(K16, Decl(keyofAndIndexedAccess.ts, 35, 19))
+
+type K17 = keyof (Shape | Item);  // "name"
+>K17 : Symbol(K17, Decl(keyofAndIndexedAccess.ts, 36, 34))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+
+type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
+>K18 : Symbol(K18, Decl(keyofAndIndexedAccess.ts, 37, 32))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Item : Symbol(Item, Decl(keyofAndIndexedAccess.ts, 6, 1))
+
+type KeyOf<T> = keyof T;
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 40, 11))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 40, 11))
+
+type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
+>K20 : Symbol(K20, Decl(keyofAndIndexedAccess.ts, 40, 24))
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type K21 = KeyOf<Dictionary<Shape>>;  // string | number
+>K21 : Symbol(K21, Decl(keyofAndIndexedAccess.ts, 42, 24))
+>KeyOf : Symbol(KeyOf, Decl(keyofAndIndexedAccess.ts, 38, 32))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type NAME = "name";
+>NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 43, 36))
+
+type WIDTH_OR_HEIGHT = "width" | "height";
+>WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 45, 19))
+
+type Q10 = Shape["name"];  // string
+>Q10 : Symbol(Q10, Decl(keyofAndIndexedAccess.ts, 46, 42))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q11 = Shape["width" | "height"];  // number
+>Q11 : Symbol(Q11, Decl(keyofAndIndexedAccess.ts, 48, 25))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q12 = Shape["name" | "visible"];  // string | boolean
+>Q12 : Symbol(Q12, Decl(keyofAndIndexedAccess.ts, 49, 37))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q20 = Shape[NAME];  // string
+>Q20 : Symbol(Q20, Decl(keyofAndIndexedAccess.ts, 50, 37))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>NAME : Symbol(NAME, Decl(keyofAndIndexedAccess.ts, 43, 36))
+
+type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
+>Q21 : Symbol(Q21, Decl(keyofAndIndexedAccess.ts, 52, 23))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>WIDTH_OR_HEIGHT : Symbol(WIDTH_OR_HEIGHT, Decl(keyofAndIndexedAccess.ts, 45, 19))
+
+type Q30 = [string, number][0];  // string
+>Q30 : Symbol(Q30, Decl(keyofAndIndexedAccess.ts, 53, 34))
+
+type Q31 = [string, number][1];  // number
+>Q31 : Symbol(Q31, Decl(keyofAndIndexedAccess.ts, 55, 31))
+
+type Q32 = [string, number][2];  // string | number
+>Q32 : Symbol(Q32, Decl(keyofAndIndexedAccess.ts, 56, 31))
+
+type Q33 = [string, number][E.A];  // string
+>Q33 : Symbol(Q33, Decl(keyofAndIndexedAccess.ts, 57, 31))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>A : Symbol(E.A, Decl(keyofAndIndexedAccess.ts, 19, 14))
+
+type Q34 = [string, number][E.B];  // number
+>Q34 : Symbol(Q34, Decl(keyofAndIndexedAccess.ts, 58, 33))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+
+type Q35 = [string, number][E.C];  // string | number
+>Q35 : Symbol(Q35, Decl(keyofAndIndexedAccess.ts, 59, 33))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>C : Symbol(E.C, Decl(keyofAndIndexedAccess.ts, 19, 20))
+
+type Q36 = [string, number]["0"];  // string
+>Q36 : Symbol(Q36, Decl(keyofAndIndexedAccess.ts, 60, 33))
+
+type Q37 = [string, number]["1"];  // string
+>Q37 : Symbol(Q37, Decl(keyofAndIndexedAccess.ts, 61, 33))
+
+type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
+>Q40 : Symbol(Q40, Decl(keyofAndIndexedAccess.ts, 62, 33))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+
+type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
+>Q41 : Symbol(Q41, Decl(keyofAndIndexedAccess.ts, 64, 40))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>Options : Symbol(Options, Decl(keyofAndIndexedAccess.ts, 11, 1))
+
+type Q50 = Dictionary<Shape>["howdy"];  // Shape
+>Q50 : Symbol(Q50, Decl(keyofAndIndexedAccess.ts, 65, 40))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q51 = Dictionary<Shape>[123];  // Shape
+>Q51 : Symbol(Q51, Decl(keyofAndIndexedAccess.ts, 67, 38))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+type Q52 = Dictionary<Shape>[E.B];  // Shape
+>Q52 : Symbol(Q52, Decl(keyofAndIndexedAccess.ts, 68, 34))
+>Dictionary : Symbol(Dictionary, Decl(keyofAndIndexedAccess.ts, 15, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>E : Symbol(E, Decl(keyofAndIndexedAccess.ts, 17, 40))
+>B : Symbol(E.B, Decl(keyofAndIndexedAccess.ts, 19, 17))
+
+declare let cond: boolean;
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 73, 23))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 73, 43))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 73, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 73, 50))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 73, 23))
+
+    return obj[key];
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 73, 43))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 73, 50))
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 77, 43))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 77, 50))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 77, 58))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 77, 21))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 77, 23))
+
+    obj[key] = value;
+>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 77, 43))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 77, 50))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 77, 58))
+}
+
+function f10(shape: Shape) {
+>f10 : Symbol(f10, Decl(keyofAndIndexedAccess.ts, 79, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let name = getProperty(shape, "name");  // string
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 82, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+
+    let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
+>widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 83, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 84, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    setProperty(shape, "name", "rectangle");
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+
+    setProperty(shape, cond ? "width" : "height", 10);
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 81, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+}
+
+function f11(a: Shape[]) {
+>f11 : Symbol(f11, Decl(keyofAndIndexedAccess.ts, 88, 1))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let len = getProperty(a, "length");  // number
+>len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 91, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+
+    let shape = getProperty(a, 1000);    // Shape
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 92, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+
+    setProperty(a, 1000, getProperty(a, 1001));
+>setProperty : Symbol(setProperty, Decl(keyofAndIndexedAccess.ts, 75, 1))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>a : Symbol(a, Decl(keyofAndIndexedAccess.ts, 90, 13))
+}
+
+function f12(t: [Shape, boolean]) {
+>f12 : Symbol(f12, Decl(keyofAndIndexedAccess.ts, 94, 1))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let len = getProperty(t, "length");
+>len : Symbol(len, Decl(keyofAndIndexedAccess.ts, 97, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let s1 = getProperty(t, 0);    // Shape
+>s1 : Symbol(s1, Decl(keyofAndIndexedAccess.ts, 98, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let s2 = getProperty(t, "0");  // Shape
+>s2 : Symbol(s2, Decl(keyofAndIndexedAccess.ts, 99, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let b1 = getProperty(t, 1);    // boolean
+>b1 : Symbol(b1, Decl(keyofAndIndexedAccess.ts, 100, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let b2 = getProperty(t, "1");  // boolean
+>b2 : Symbol(b2, Decl(keyofAndIndexedAccess.ts, 101, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+
+    let x1 = getProperty(t, 2);    // Shape | boolean
+>x1 : Symbol(x1, Decl(keyofAndIndexedAccess.ts, 102, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 96, 13))
+}
+
+function f13(foo: any, bar: any) {
+>f13 : Symbol(f13, Decl(keyofAndIndexedAccess.ts, 103, 1))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+>bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 105, 22))
+
+    let x = getProperty(foo, "x");  // any
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 106, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+
+    let y = getProperty(foo, 100);  // any
+>y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 107, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+
+    let z = getProperty(foo, bar);  // any
+>z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 108, 7))
+>getProperty : Symbol(getProperty, Decl(keyofAndIndexedAccess.ts, 71, 26))
+>foo : Symbol(foo, Decl(keyofAndIndexedAccess.ts, 105, 13))
+>bar : Symbol(bar, Decl(keyofAndIndexedAccess.ts, 105, 22))
+}
+
+class Component<PropType> {
+>Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+
+    props: PropType;
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+
+    getProperty<K extends keyof PropType>(key: K) {
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 113, 16))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 113, 42))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 113, 16))
+
+        return this.props[key];
+>this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 113, 42))
+    }
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 116, 42))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 116, 49))
+>PropType : Symbol(PropType, Decl(keyofAndIndexedAccess.ts, 111, 16))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 116, 16))
+
+        this.props[key] = value;
+>this.props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>this : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>props : Symbol(Component.props, Decl(keyofAndIndexedAccess.ts, 111, 27))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 116, 42))
+>value : Symbol(value, Decl(keyofAndIndexedAccess.ts, 116, 49))
+    }
+}
+
+function f20(component: Component<Shape>) {
+>f20 : Symbol(f20, Decl(keyofAndIndexedAccess.ts, 119, 1))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>Component : Symbol(Component, Decl(keyofAndIndexedAccess.ts, 109, 1))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let name = component.getProperty("name");  // string
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 122, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+
+    let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
+>widthOrHeight : Symbol(widthOrHeight, Decl(keyofAndIndexedAccess.ts, 123, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : Symbol(nameOrVisible, Decl(keyofAndIndexedAccess.ts, 124, 7))
+>component.getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>getProperty : Symbol(Component.getProperty, Decl(keyofAndIndexedAccess.ts, 112, 20))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    component.setProperty("name", "rectangle");
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+
+    component.setProperty(cond ? "width" : "height", 10)
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+
+    component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
+>component.setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>component : Symbol(component, Decl(keyofAndIndexedAccess.ts, 121, 13))
+>setProperty : Symbol(Component.setProperty, Decl(keyofAndIndexedAccess.ts, 115, 5))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+}
+
+function pluck<T, K extends keyof T>(array: T[], key: K) {
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 130, 17))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
+>array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 130, 37))
+>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 130, 15))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 130, 48))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 130, 17))
+
+    return array.map(x => x[key]);
+>array.map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>array : Symbol(array, Decl(keyofAndIndexedAccess.ts, 130, 37))
+>map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 131, 21))
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 131, 21))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 130, 48))
+}
+
+function f30(shapes: Shape[]) {
+>f30 : Symbol(f30, Decl(keyofAndIndexedAccess.ts, 132, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+
+    let names = pluck(shapes, "name");    // string[]
+>names : Symbol(names, Decl(keyofAndIndexedAccess.ts, 135, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+
+    let widths = pluck(shapes, "width");  // number[]
+>widths : Symbol(widths, Decl(keyofAndIndexedAccess.ts, 136, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+
+    let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
+>nameOrVisibles : Symbol(nameOrVisibles, Decl(keyofAndIndexedAccess.ts, 137, 7))
+>pluck : Symbol(pluck, Decl(keyofAndIndexedAccess.ts, 128, 1))
+>shapes : Symbol(shapes, Decl(keyofAndIndexedAccess.ts, 134, 13))
+>cond : Symbol(cond, Decl(keyofAndIndexedAccess.ts, 71, 11))
+}
+
+function f31<K extends keyof Shape>(key: K) {
+>f31 : Symbol(f31, Decl(keyofAndIndexedAccess.ts, 138, 1))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 140, 13))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 140, 36))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 140, 13))
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 141, 9))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 141, 26))
+>width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 141, 39))
+>height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 141, 49))
+>visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 141, 61))
+
+    return shape[key];  // Shape[K]
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 141, 9))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 140, 36))
+}
+
+function f32<K extends "width" | "height">(key: K) {
+>f32 : Symbol(f32, Decl(keyofAndIndexedAccess.ts, 143, 1))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 145, 13))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 145, 43))
+>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 145, 13))
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 146, 9))
+>Shape : Symbol(Shape, Decl(keyofAndIndexedAccess.ts, 0, 0))
+>name : Symbol(name, Decl(keyofAndIndexedAccess.ts, 146, 26))
+>width : Symbol(width, Decl(keyofAndIndexedAccess.ts, 146, 39))
+>height : Symbol(height, Decl(keyofAndIndexedAccess.ts, 146, 49))
+>visible : Symbol(visible, Decl(keyofAndIndexedAccess.ts, 146, 61))
+
+    return shape[key];  // Shape[K]
+>shape : Symbol(shape, Decl(keyofAndIndexedAccess.ts, 146, 9))
+>key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 145, 43))
+}
+
+class C {
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    public x: string;
+>x : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 150, 9))
+
+    protected y: string;
+>y : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 151, 21))
+
+    private z: string;
+>z : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 152, 24))
+}
+
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c: C) {
+>f40 : Symbol(f40, Decl(keyofAndIndexedAccess.ts, 154, 1))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    type X = C["x"];
+>X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 158, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    type Y = C["y"];
+>Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 159, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    type Z = C["z"];
+>Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 160, 20))
+>C : Symbol(C, Decl(keyofAndIndexedAccess.ts, 148, 1))
+
+    let x: X = c["x"];
+>x : Symbol(x, Decl(keyofAndIndexedAccess.ts, 162, 7))
+>X : Symbol(X, Decl(keyofAndIndexedAccess.ts, 158, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>"x" : Symbol(C.x, Decl(keyofAndIndexedAccess.ts, 150, 9))
+
+    let y: Y = c["y"];
+>y : Symbol(y, Decl(keyofAndIndexedAccess.ts, 163, 7))
+>Y : Symbol(Y, Decl(keyofAndIndexedAccess.ts, 159, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>"y" : Symbol(C.y, Decl(keyofAndIndexedAccess.ts, 151, 21))
+
+    let z: Z = c["z"];
+>z : Symbol(z, Decl(keyofAndIndexedAccess.ts, 164, 7))
+>Z : Symbol(Z, Decl(keyofAndIndexedAccess.ts, 160, 20))
+>c : Symbol(c, Decl(keyofAndIndexedAccess.ts, 158, 13))
+>"z" : Symbol(C.z, Decl(keyofAndIndexedAccess.ts, 152, 24))
+}

tests/baselines/reference/keyofAndIndexedAccess.types

@@ -0,0 +1,681 @@
+=== tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts ===
+
+class Shape {
+>Shape : Shape
+
+    name: string;
+>name : string
+
+    width: number;
+>width : number
+
+    height: number;
+>height : number
+
+    visible: boolean;
+>visible : boolean
+}
+
+class Item {
+>Item : Item
+
+    name: string;
+>name : string
+
+    price: number;
+>price : number
+}
+
+class Options {
+>Options : Options
+
+    visible: "yes" | "no";
+>visible : "yes" | "no"
+}
+
+type Dictionary<T> = { [x: string]: T };
+>Dictionary : { [x: string]: T; }
+>T : T
+>x : string
+>T : T
+
+const enum E { A, B, C }
+>E : E
+>A : E.A
+>B : E.B
+>C : E.C
+
+type K00 = keyof any;  // string | number
+>K00 : string | number
+
+type K01 = keyof string;  // number | "toString" | "charAt" | ...
+>K01 : number | "length" | "toString" | "concat" | "slice" | "indexOf" | "lastIndexOf" | "charAt" | "charCodeAt" | "localeCompare" | "match" | "replace" | "search" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr" | "valueOf"
+
+type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
+>K02 : "toString" | "toLocaleString" | "valueOf" | "toFixed" | "toExponential" | "toPrecision"
+
+type K03 = keyof boolean;  // "valueOf"
+>K03 : "valueOf"
+
+type K04 = keyof void;  // never
+>K04 : never
+
+type K05 = keyof undefined;  // never
+>K05 : never
+
+type K06 = keyof null;  // never
+>K06 : never
+>null : null
+
+type K07 = keyof never;  // never
+>K07 : never
+
+type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
+>K10 : "name" | "width" | "height" | "visible"
+>Shape : Shape
+
+type K11 = keyof Shape[];  // number | "length" | "toString" | ...
+>K11 : number | "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
+>Shape : Shape
+
+type K12 = keyof Dictionary<Shape>;  // string | number
+>K12 : string | number
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type K13 = keyof {};  // never
+>K13 : never
+
+type K14 = keyof Object;  // "constructor" | "toString" | ...
+>K14 : "toString" | "toLocaleString" | "valueOf" | "constructor" | "hasOwnProperty" | "isPrototypeOf" | "propertyIsEnumerable"
+>Object : Object
+
+type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
+>K15 : "toString" | "toLocaleString" | "valueOf" | "toFixed" | "toExponential" | "toPrecision"
+>E : E
+
+type K16 = keyof [string, number];  // number | "0" | "1" | "length" | "toString" | ...
+>K16 : number | "0" | "1" | "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
+
+type K17 = keyof (Shape | Item);  // "name"
+>K17 : "name"
+>Shape : Shape
+>Item : Item
+
+type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "price"
+>K18 : "name" | "width" | "height" | "visible" | "price"
+>Shape : Shape
+>Item : Item
+
+type KeyOf<T> = keyof T;
+>KeyOf : keyof T
+>T : T
+>T : T
+
+type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
+>K20 : "name" | "width" | "height" | "visible"
+>KeyOf : keyof T
+>Shape : Shape
+
+type K21 = KeyOf<Dictionary<Shape>>;  // string | number
+>K21 : string | number
+>KeyOf : keyof T
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type NAME = "name";
+>NAME : "name"
+
+type WIDTH_OR_HEIGHT = "width" | "height";
+>WIDTH_OR_HEIGHT : "width" | "height"
+
+type Q10 = Shape["name"];  // string
+>Q10 : string
+>Shape : Shape
+
+type Q11 = Shape["width" | "height"];  // number
+>Q11 : number
+>Shape : Shape
+
+type Q12 = Shape["name" | "visible"];  // string | boolean
+>Q12 : string | boolean
+>Shape : Shape
+
+type Q20 = Shape[NAME];  // string
+>Q20 : string
+>Shape : Shape
+>NAME : "name"
+
+type Q21 = Shape[WIDTH_OR_HEIGHT];  // number
+>Q21 : number
+>Shape : Shape
+>WIDTH_OR_HEIGHT : "width" | "height"
+
+type Q30 = [string, number][0];  // string
+>Q30 : string
+
+type Q31 = [string, number][1];  // number
+>Q31 : number
+
+type Q32 = [string, number][2];  // string | number
+>Q32 : string | number
+
+type Q33 = [string, number][E.A];  // string
+>Q33 : string
+>E : any
+>A : E.A
+
+type Q34 = [string, number][E.B];  // number
+>Q34 : number
+>E : any
+>B : E.B
+
+type Q35 = [string, number][E.C];  // string | number
+>Q35 : string | number
+>E : any
+>C : E.C
+
+type Q36 = [string, number]["0"];  // string
+>Q36 : string
+
+type Q37 = [string, number]["1"];  // string
+>Q37 : number
+
+type Q40 = (Shape | Options)["visible"];  // boolean | "yes" | "no"
+>Q40 : boolean | "yes" | "no"
+>Shape : Shape
+>Options : Options
+
+type Q41 = (Shape & Options)["visible"];  // true & "yes" | true & "no" | false & "yes" | false & "no"
+>Q41 : (true & "yes") | (true & "no") | (false & "yes") | (false & "no")
+>Shape : Shape
+>Options : Options
+
+type Q50 = Dictionary<Shape>["howdy"];  // Shape
+>Q50 : Shape
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type Q51 = Dictionary<Shape>[123];  // Shape
+>Q51 : Shape
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+
+type Q52 = Dictionary<Shape>[E.B];  // Shape
+>Q52 : Shape
+>Dictionary : { [x: string]: T; }
+>Shape : Shape
+>E : any
+>B : E.B
+
+declare let cond: boolean;
+>cond : boolean
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>T : T
+>K : K
+>T : T
+>obj : T
+>T : T
+>key : K
+>K : K
+
+    return obj[key];
+>obj[key] : T[K]
+>obj : T
+>key : K
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>T : T
+>K : K
+>T : T
+>obj : T
+>T : T
+>key : K
+>K : K
+>value : T[K]
+>T : T
+>K : K
+
+    obj[key] = value;
+>obj[key] = value : T[K]
+>obj[key] : T[K]
+>obj : T
+>key : K
+>value : T[K]
+}
+
+function f10(shape: Shape) {
+>f10 : (shape: Shape) => void
+>shape : Shape
+>Shape : Shape
+
+    let name = getProperty(shape, "name");  // string
+>name : string
+>getProperty(shape, "name") : string
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : Shape
+>"name" : "name"
+
+    let widthOrHeight = getProperty(shape, cond ? "width" : "height");  // number
+>widthOrHeight : number
+>getProperty(shape, cond ? "width" : "height") : number
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : Shape
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+
+    let nameOrVisible = getProperty(shape, cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : string | boolean
+>getProperty(shape, cond ? "name" : "visible") : string | boolean
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>shape : Shape
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+
+    setProperty(shape, "name", "rectangle");
+>setProperty(shape, "name", "rectangle") : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>shape : Shape
+>"name" : "name"
+>"rectangle" : "rectangle"
+
+    setProperty(shape, cond ? "width" : "height", 10);
+>setProperty(shape, cond ? "width" : "height", 10) : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>shape : Shape
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+>10 : 10
+
+    setProperty(shape, cond ? "name" : "visible", true);  // Technically not safe
+>setProperty(shape, cond ? "name" : "visible", true) : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>shape : Shape
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+>true : true
+}
+
+function f11(a: Shape[]) {
+>f11 : (a: Shape[]) => void
+>a : Shape[]
+>Shape : Shape
+
+    let len = getProperty(a, "length");  // number
+>len : number
+>getProperty(a, "length") : number
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>a : Shape[]
+>"length" : "length"
+
+    let shape = getProperty(a, 1000);    // Shape
+>shape : Shape
+>getProperty(a, 1000) : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>a : Shape[]
+>1000 : 1000
+
+    setProperty(a, 1000, getProperty(a, 1001));
+>setProperty(a, 1000, getProperty(a, 1001)) : void
+>setProperty : <T, K extends keyof T>(obj: T, key: K, value: T[K]) => void
+>a : Shape[]
+>1000 : 1000
+>getProperty(a, 1001) : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>a : Shape[]
+>1001 : 1001
+}
+
+function f12(t: [Shape, boolean]) {
+>f12 : (t: [Shape, boolean]) => void
+>t : [Shape, boolean]
+>Shape : Shape
+
+    let len = getProperty(t, "length");
+>len : number
+>getProperty(t, "length") : number
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>"length" : "length"
+
+    let s1 = getProperty(t, 0);    // Shape
+>s1 : Shape
+>getProperty(t, 0) : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>0 : 0
+
+    let s2 = getProperty(t, "0");  // Shape
+>s2 : Shape
+>getProperty(t, "0") : Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>"0" : "0"
+
+    let b1 = getProperty(t, 1);    // boolean
+>b1 : boolean
+>getProperty(t, 1) : boolean
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>1 : 1
+
+    let b2 = getProperty(t, "1");  // boolean
+>b2 : boolean
+>getProperty(t, "1") : boolean
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>"1" : "1"
+
+    let x1 = getProperty(t, 2);    // Shape | boolean
+>x1 : boolean | Shape
+>getProperty(t, 2) : boolean | Shape
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>t : [Shape, boolean]
+>2 : 2
+}
+
+function f13(foo: any, bar: any) {
+>f13 : (foo: any, bar: any) => void
+>foo : any
+>bar : any
+
+    let x = getProperty(foo, "x");  // any
+>x : any
+>getProperty(foo, "x") : any
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>foo : any
+>"x" : "x"
+
+    let y = getProperty(foo, 100);  // any
+>y : any
+>getProperty(foo, 100) : any
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>foo : any
+>100 : 100
+
+    let z = getProperty(foo, bar);  // any
+>z : any
+>getProperty(foo, bar) : any
+>getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
+>foo : any
+>bar : any
+}
+
+class Component<PropType> {
+>Component : Component<PropType>
+>PropType : PropType
+
+    props: PropType;
+>props : PropType
+>PropType : PropType
+
+    getProperty<K extends keyof PropType>(key: K) {
+>getProperty : <K extends keyof PropType>(key: K) => PropType[K]
+>K : K
+>PropType : PropType
+>key : K
+>K : K
+
+        return this.props[key];
+>this.props[key] : PropType[K]
+>this.props : PropType
+>this : this
+>props : PropType
+>key : K
+    }
+    setProperty<K extends keyof PropType>(key: K, value: PropType[K]) {
+>setProperty : <K extends keyof PropType>(key: K, value: PropType[K]) => void
+>K : K
+>PropType : PropType
+>key : K
+>K : K
+>value : PropType[K]
+>PropType : PropType
+>K : K
+
+        this.props[key] = value;
+>this.props[key] = value : PropType[K]
+>this.props[key] : PropType[K]
+>this.props : PropType
+>this : this
+>props : PropType
+>key : K
+>value : PropType[K]
+    }
+}
+
+function f20(component: Component<Shape>) {
+>f20 : (component: Component<Shape>) => void
+>component : Component<Shape>
+>Component : Component<PropType>
+>Shape : Shape
+
+    let name = component.getProperty("name");  // string
+>name : string
+>component.getProperty("name") : string
+>component.getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>component : Component<Shape>
+>getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>"name" : "name"
+
+    let widthOrHeight = component.getProperty(cond ? "width" : "height");  // number
+>widthOrHeight : number
+>component.getProperty(cond ? "width" : "height") : number
+>component.getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>component : Component<Shape>
+>getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+
+    let nameOrVisible = component.getProperty(cond ? "name" : "visible");  // string | boolean
+>nameOrVisible : string | boolean
+>component.getProperty(cond ? "name" : "visible") : string | boolean
+>component.getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>component : Component<Shape>
+>getProperty : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+
+    component.setProperty("name", "rectangle");
+>component.setProperty("name", "rectangle") : void
+>component.setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>component : Component<Shape>
+>setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>"name" : "name"
+>"rectangle" : "rectangle"
+
+    component.setProperty(cond ? "width" : "height", 10)
+>component.setProperty(cond ? "width" : "height", 10) : void
+>component.setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>component : Component<Shape>
+>setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>cond ? "width" : "height" : "width" | "height"
+>cond : boolean
+>"width" : "width"
+>"height" : "height"
+>10 : 10
+
+    component.setProperty(cond ? "name" : "visible", true);  // Technically not safe
+>component.setProperty(cond ? "name" : "visible", true) : void
+>component.setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>component : Component<Shape>
+>setProperty : <K extends "name" | "width" | "height" | "visible">(key: K, value: Shape[K]) => void
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+>true : true
+}
+
+function pluck<T, K extends keyof T>(array: T[], key: K) {
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>T : T
+>K : K
+>T : T
+>array : T[]
+>T : T
+>key : K
+>K : K
+
+    return array.map(x => x[key]);
+>array.map(x => x[key]) : T[K][]
+>array.map : { <U>(this: [T, T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U]; <U>(this: [T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; }
+>array : T[]
+>map : { <U>(this: [T, T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [T, T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [T, T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U, U]; <U>(this: [T, T], callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; }
+>x => x[key] : (x: T) => T[K]
+>x : T
+>x[key] : T[K]
+>x : T
+>key : K
+}
+
+function f30(shapes: Shape[]) {
+>f30 : (shapes: Shape[]) => void
+>shapes : Shape[]
+>Shape : Shape
+
+    let names = pluck(shapes, "name");    // string[]
+>names : string[]
+>pluck(shapes, "name") : string[]
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>shapes : Shape[]
+>"name" : "name"
+
+    let widths = pluck(shapes, "width");  // number[]
+>widths : number[]
+>pluck(shapes, "width") : number[]
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>shapes : Shape[]
+>"width" : "width"
+
+    let nameOrVisibles = pluck(shapes, cond ? "name" : "visible");  // (string | boolean)[]
+>nameOrVisibles : (string | boolean)[]
+>pluck(shapes, cond ? "name" : "visible") : (string | boolean)[]
+>pluck : <T, K extends keyof T>(array: T[], key: K) => T[K][]
+>shapes : Shape[]
+>cond ? "name" : "visible" : "name" | "visible"
+>cond : boolean
+>"name" : "name"
+>"visible" : "visible"
+}
+
+function f31<K extends keyof Shape>(key: K) {
+>f31 : <K extends "name" | "width" | "height" | "visible">(key: K) => Shape[K]
+>K : K
+>Shape : Shape
+>key : K
+>K : K
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Shape
+>Shape : Shape
+>{ name: "foo", width: 5, height: 10, visible: true } : { name: string; width: number; height: number; visible: true; }
+>name : string
+>"foo" : "foo"
+>width : number
+>5 : 5
+>height : number
+>10 : 10
+>visible : boolean
+>true : true
+
+    return shape[key];  // Shape[K]
+>shape[key] : Shape[K]
+>shape : Shape
+>key : K
+}
+
+function f32<K extends "width" | "height">(key: K) {
+>f32 : <K extends "width" | "height">(key: K) => Shape[K]
+>K : K
+>key : K
+>K : K
+
+    const shape: Shape = { name: "foo", width: 5, height: 10, visible: true };
+>shape : Shape
+>Shape : Shape
+>{ name: "foo", width: 5, height: 10, visible: true } : { name: string; width: number; height: number; visible: true; }
+>name : string
+>"foo" : "foo"
+>width : number
+>5 : 5
+>height : number
+>10 : 10
+>visible : boolean
+>true : true
+
+    return shape[key];  // Shape[K]
+>shape[key] : Shape[K]
+>shape : Shape
+>key : K
+}
+
+class C {
+>C : C
+
+    public x: string;
+>x : string
+
+    protected y: string;
+>y : string
+
+    private z: string;
+>z : string
+}
+
+// Indexed access expressions have always permitted access to private and protected members.
+// For consistency we also permit such access in indexed access types.
+function f40(c: C) {
+>f40 : (c: C) => void
+>c : C
+>C : C
+
+    type X = C["x"];
+>X : string
+>C : C
+
+    type Y = C["y"];
+>Y : string
+>C : C
+
+    type Z = C["z"];
+>Z : string
+>C : C
+
+    let x: X = c["x"];
+>x : string
+>X : string
+>c["x"] : string
+>c : C
+>"x" : "x"
+
+    let y: Y = c["y"];
+>y : string
+>Y : string
+>c["y"] : string
+>c : C
+>"y" : "y"
+
+    let z: Z = c["z"];
+>z : string
+>Z : string
+>c["z"] : string
+>c : C
+>"z" : "z"
+}

tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt

@@ -0,0 +1,138 @@
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(10,18): error TS2304: Cannot find name 'K0'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(20,18): error TS2339: Property 'foo' does not exist on type 'Shape'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(21,18): error TS2339: Property 'foo' does not exist on type 'Shape'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(22,18): error TS2538: Type 'any' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(23,18): error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(24,18): error TS2537: Type 'Shape' has no matching index signature for type 'number'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(25,18): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(26,18): error TS2538: Type 'void' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(27,18): error TS2538: Type 'undefined' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(28,18): error TS2538: Type '{ x: string; }' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(29,18): error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(30,18): error TS2538: Type 'string & number' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(31,18): error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(35,21): error TS2537: Type 'string[]' has no matching index signature for type 'string'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(36,21): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(41,31): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(46,16): error TS2538: Type 'boolean' cannot be used as an index type.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(63,33): error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(64,33): error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+  Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(66,24): error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(67,24): error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+  Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+
+
+==== tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts (21 errors) ====
+    class Shape {
+        name: string;
+        width: number;
+        height: number;
+        visible: boolean;
+    }
+    
+    type Dictionary<T> = { [x: string]: T };
+    
+    type T00 = keyof K0;  // Error
+                     ~~
+!!! error TS2304: Cannot find name 'K0'.
+    
+    type T01 = keyof Object;
+    type T02 = keyof keyof Object;
+    type T03 = keyof keyof keyof Object;
+    type T04 = keyof keyof keyof keyof Object;
+    type T05 = keyof keyof keyof keyof keyof Object;
+    type T06 = keyof keyof keyof keyof keyof keyof Object;
+    
+    type T10 = Shape["name"];
+    type T11 = Shape["foo"];  // Error
+                     ~~~~~
+!!! error TS2339: Property 'foo' does not exist on type 'Shape'.
+    type T12 = Shape["name" | "foo"];  // Error
+                     ~~~~~~~~~~~~~~
+!!! error TS2339: Property 'foo' does not exist on type 'Shape'.
+    type T13 = Shape[any];  // Error
+                     ~~~
+!!! error TS2538: Type 'any' cannot be used as an index type.
+    type T14 = Shape[string];  // Error
+                     ~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+    type T15 = Shape[number];  // Error
+                     ~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'number'.
+    type T16 = Shape[boolean];  // Error
+                     ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    type T17 = Shape[void];  // Error
+                     ~~~~
+!!! error TS2538: Type 'void' cannot be used as an index type.
+    type T18 = Shape[undefined];  // Error
+                     ~~~~~~~~~
+!!! error TS2538: Type 'undefined' cannot be used as an index type.
+    type T19 = Shape[{ x: string }];  // Error
+                     ~~~~~~~~~~~~~
+!!! error TS2538: Type '{ x: string; }' cannot be used as an index type.
+    type T20 = Shape[string | number];  // Error
+                     ~~~~~~~~~~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+    type T21 = Shape[string & number];  // Error
+                     ~~~~~~~~~~~~~~~
+!!! error TS2538: Type 'string & number' cannot be used as an index type.
+    type T22 = Shape[string | boolean];  // Error
+                     ~~~~~~~~~~~~~~~~
+!!! error TS2537: Type 'Shape' has no matching index signature for type 'string'.
+    
+    type T30 = string[]["length"];
+    type T31 = string[][number];
+    type T32 = string[][string];  // Error
+                        ~~~~~~
+!!! error TS2537: Type 'string[]' has no matching index signature for type 'string'.
+    type T33 = string[][boolean];  // Error
+                        ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    
+    type T40 = Dictionary<string>[any];
+    type T41 = Dictionary<string>[number];
+    type T42 = Dictionary<string>[string];
+    type T43 = Dictionary<string>[boolean];  // Error
+                                  ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    
+    type T50 = any[any];
+    type T51 = any[number];
+    type T52 = any[string];
+    type T53 = any[boolean];  // Error
+                   ~~~~~~~
+!!! error TS2538: Type 'boolean' cannot be used as an index type.
+    
+    type T60 = {}["toString"];
+    type T61 = []["toString"];
+    
+    declare let cond: boolean;
+    
+    function getProperty<T, K extends keyof T>(obj: T, key: K) {
+        return obj[key];
+    }
+    
+    function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+        obj[key] = value;
+    }
+    
+    function f10(shape: Shape) {
+        let x1 = getProperty(shape, "name");
+        let x2 = getProperty(shape, "size");  // Error
+                                    ~~~~~~
+!!! error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+        let x3 = getProperty(shape, cond ? "name" : "size");  // Error
+                                    ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+!!! error TS2345:   Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+        setProperty(shape, "name", "rectangle");
+        setProperty(shape, "size", 10);  // Error
+                           ~~~~~~
+!!! error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+        setProperty(shape, cond ? "name" : "size", 10);  // Error
+                           ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
+!!! error TS2345:   Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
+    }

tests/baselines/reference/keyofAndIndexedAccessErrors.js

@@ -0,0 +1,90 @@
+//// [keyofAndIndexedAccessErrors.ts]
+class Shape {
+    name: string;
+    width: number;
+    height: number;
+    visible: boolean;
+}
+
+type Dictionary<T> = { [x: string]: T };
+
+type T00 = keyof K0;  // Error
+
+type T01 = keyof Object;
+type T02 = keyof keyof Object;
+type T03 = keyof keyof keyof Object;
+type T04 = keyof keyof keyof keyof Object;
+type T05 = keyof keyof keyof keyof keyof Object;
+type T06 = keyof keyof keyof keyof keyof keyof Object;
+
+type T10 = Shape["name"];
+type T11 = Shape["foo"];  // Error
+type T12 = Shape["name" | "foo"];  // Error
+type T13 = Shape[any];  // Error
+type T14 = Shape[string];  // Error
+type T15 = Shape[number];  // Error
+type T16 = Shape[boolean];  // Error
+type T17 = Shape[void];  // Error
+type T18 = Shape[undefined];  // Error
+type T19 = Shape[{ x: string }];  // Error
+type T20 = Shape[string | number];  // Error
+type T21 = Shape[string & number];  // Error
+type T22 = Shape[string | boolean];  // Error
+
+type T30 = string[]["length"];
+type T31 = string[][number];
+type T32 = string[][string];  // Error
+type T33 = string[][boolean];  // Error
+
+type T40 = Dictionary<string>[any];
+type T41 = Dictionary<string>[number];
+type T42 = Dictionary<string>[string];
+type T43 = Dictionary<string>[boolean];  // Error
+
+type T50 = any[any];
+type T51 = any[number];
+type T52 = any[string];
+type T53 = any[boolean];  // Error
+
+type T60 = {}["toString"];
+type T61 = []["toString"];
+
+declare let cond: boolean;
+
+function getProperty<T, K extends keyof T>(obj: T, key: K) {
+    return obj[key];
+}
+
+function setProperty<T, K extends keyof T>(obj: T, key: K, value: T[K]) {
+    obj[key] = value;
+}
+
+function f10(shape: Shape) {
+    let x1 = getProperty(shape, "name");
+    let x2 = getProperty(shape, "size");  // Error
+    let x3 = getProperty(shape, cond ? "name" : "size");  // Error
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, "size", 10);  // Error
+    setProperty(shape, cond ? "name" : "size", 10);  // Error
+}
+
+//// [keyofAndIndexedAccessErrors.js]
+var Shape = (function () {
+    function Shape() {
+    }
+    return Shape;
+}());
+function getProperty(obj, key) {
+    return obj[key];
+}
+function setProperty(obj, key, value) {
+    obj[key] = value;
+}
+function f10(shape) {
+    var x1 = getProperty(shape, "name");
+    var x2 = getProperty(shape, "size"); // Error
+    var x3 = getProperty(shape, cond ? "name" : "size"); // Error
+    setProperty(shape, "name", "rectangle");
+    setProperty(shape, "size", 10); // Error
+    setProperty(shape, cond ? "name" : "size", 10); // Error
+}

tests/baselines/reference/moduleResolutionWithExtensions_notSupported3.errors.txt

@@ -0,0 +1,12 @@
+/a.ts(1,17): error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+
+
+==== /a.ts (1 errors) ====
+    import jsx from "./jsx";
+                    ~~~~~~~
+!!! error TS6143: Module './jsx' was resolved to '/jsx.jsx', but '--allowJs' is not set.
+    
+==== /jsx.jsx (0 errors) ====
+    // Test the error message if we have `--jsx` but not `--allowJw`.
+    
+