Merge branch 'master' into mappedTypes

# Conflicts:
#	src/compiler/checker.ts

Jakefile.js

@@ -71,6 +71,7 @@ var compilerSources = [
     "transformers/destructuring.ts",
     "transformers/ts.ts",
     "transformers/jsx.ts",
+    "transformers/esnext.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",
@@ -107,6 +108,7 @@ var servicesSources = [
     "transformers/destructuring.ts",
     "transformers/ts.ts",
     "transformers/jsx.ts",
+    "transformers/esnext.ts",
     "transformers/es2017.ts",
     "transformers/es2016.ts",
     "transformers/es2015.ts",

src/compiler/binder.ts

@@ -1139,8 +1139,8 @@ namespace ts {
             }
             else if (node.kind === SyntaxKind.ArrayLiteralExpression) {
                 for (const e of (<ArrayLiteralExpression>node).elements) {
-                    if (e.kind === SyntaxKind.SpreadElementExpression) {
-                        bindAssignmentTargetFlow((<SpreadElementExpression>e).expression);
+                    if (e.kind === SyntaxKind.SpreadElement) {
+                        bindAssignmentTargetFlow((<SpreadElement>e).expression);
                     }
                     else {
                         bindDestructuringTargetFlow(e);
@@ -1155,6 +1155,9 @@ namespace ts {
                     else if (p.kind === SyntaxKind.ShorthandPropertyAssignment) {
                         bindAssignmentTargetFlow((<ShorthandPropertyAssignment>p).name);
                     }
+                    else if (p.kind === SyntaxKind.SpreadAssignment) {
+                        bindAssignmentTargetFlow((<SpreadAssignment>p).expression);
+                    }
                 }
             }
         }
@@ -1918,6 +1921,9 @@ namespace ts {
                     return bindParameter(<ParameterDeclaration>node);
                 case SyntaxKind.VariableDeclaration:
                 case SyntaxKind.BindingElement:
+                    if ((node as BindingElement).dotDotDotToken && node.parent.kind === SyntaxKind.ObjectBindingPattern) {
+                        emitFlags |= NodeFlags.HasRestAttribute;
+                    }
                     return bindVariableDeclarationOrBindingElement(<VariableDeclaration | BindingElement>node);
                 case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.PropertySignature:
@@ -1931,8 +1937,21 @@ namespace ts {
                 case SyntaxKind.EnumMember:
                     return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.EnumMember, SymbolFlags.EnumMemberExcludes);
 
+                case SyntaxKind.SpreadAssignment:
                 case SyntaxKind.JsxSpreadAttribute:
-                    emitFlags |= NodeFlags.HasJsxSpreadAttributes;
+                    let root = container;
+                    let hasRest = false;
+                    while (root.parent) {
+                        if (root.kind === SyntaxKind.ObjectLiteralExpression &&
+                            root.parent.kind === SyntaxKind.BinaryExpression &&
+                            (root.parent as BinaryExpression).operatorToken.kind === SyntaxKind.EqualsToken &&
+                            (root.parent as BinaryExpression).left === root) {
+                            hasRest = true;
+                            break;
+                        }
+                        root = root.parent;
+                    }
+                    emitFlags |= hasRest ? NodeFlags.HasRestAttribute : NodeFlags.HasSpreadAttribute;
                     return;
 
                 case SyntaxKind.CallSignature:
@@ -2498,9 +2517,9 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
 
-        if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression
             || isSuperOrSuperProperty(expression, expressionKind)) {
-            // If the this node contains a SpreadElementExpression, or is a super call, then it is an ES6
+            // If the this node contains a SpreadExpression, or is a super call, then it is an ES6
             // node.
             transformFlags |= TransformFlags.AssertES2015;
         }
@@ -2529,7 +2548,7 @@ namespace ts {
         if (node.typeArguments) {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
-        if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression) {
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
             // If the this node contains a SpreadElementExpression then it is an ES6
             // node.
             transformFlags |= TransformFlags.AssertES2015;
@@ -2544,10 +2563,13 @@ namespace ts {
         const operatorTokenKind = node.operatorToken.kind;
         const leftKind = node.left.kind;
 
-        if (operatorTokenKind === SyntaxKind.EqualsToken
-            && (leftKind === SyntaxKind.ObjectLiteralExpression
-                || leftKind === SyntaxKind.ArrayLiteralExpression)) {
-            // Destructuring assignments are ES6 syntax.
+        if (operatorTokenKind === SyntaxKind.EqualsToken && leftKind === SyntaxKind.ObjectLiteralExpression) {
+            // Destructuring object assignments with are ES2015 syntax
+            // and possibly ESNext if they contain rest
+            transformFlags |= TransformFlags.AssertESNext | TransformFlags.AssertES2015 | TransformFlags.AssertDestructuringAssignment;
+        }
+        else if (operatorTokenKind === SyntaxKind.EqualsToken && leftKind === SyntaxKind.ArrayLiteralExpression) {
+            // Destructuring assignments are ES2015 syntax.
             transformFlags |= TransformFlags.AssertES2015 | TransformFlags.AssertDestructuringAssignment;
         }
         else if (operatorTokenKind === SyntaxKind.AsteriskAsteriskToken
@@ -2581,6 +2603,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertTypeScript | TransformFlags.ContainsParameterPropertyAssignments;
         }
 
+        // parameters with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         // If a parameter has an initializer, a binding pattern or a dotDotDot token, then
         // it is ES6 syntax and its container must emit default value assignments or parameter destructuring downlevel.
         if (subtreeFlags & TransformFlags.ContainsBindingPattern || initializer || dotDotDotToken) {
@@ -2814,6 +2841,11 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertES2017;
             }
 
+            // function declarations with object rest destructuring are ES Next syntax
+            if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+                transformFlags |= TransformFlags.AssertESNext;
+            }
+
             // If a FunctionDeclaration's subtree has marked the container as needing to capture the
             // lexical this, or the function contains parameters with initializers, then this node is
             // ES6 syntax.
@@ -2851,6 +2883,12 @@ namespace ts {
             transformFlags |= TransformFlags.AssertES2017;
         }
 
+        // function expressions with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
+
         // If a FunctionExpression's subtree has marked the container as needing to capture the
         // lexical this, or the function contains parameters with initializers, then this node is
         // ES6 syntax.
@@ -2888,6 +2926,11 @@ namespace ts {
             transformFlags |= TransformFlags.AssertES2017;
         }
 
+        // arrow functions with object rest destructuring are ES Next syntax
+        if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+            transformFlags |= TransformFlags.AssertESNext;
+        }
+
         // If an ArrowFunction contains a lexical this, its container must capture the lexical this.
         if (subtreeFlags & TransformFlags.ContainsLexicalThis) {
             transformFlags |= TransformFlags.ContainsCapturedLexicalThis;
@@ -2916,8 +2959,13 @@ namespace ts {
         let transformFlags = subtreeFlags;
         const nameKind = node.name.kind;
 
-        // A VariableDeclaration with a binding pattern is ES6 syntax.
-        if (nameKind === SyntaxKind.ObjectBindingPattern || nameKind === SyntaxKind.ArrayBindingPattern) {
+        // A VariableDeclaration with an object binding pattern is ES2015 syntax
+        // and possibly ESNext syntax if it contains an object binding pattern
+        if (nameKind === SyntaxKind.ObjectBindingPattern) {
+            transformFlags |= TransformFlags.AssertESNext | TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+        }
+        // A VariableDeclaration with an object binding pattern is ES2015 syntax.
+        else if (nameKind === SyntaxKind.ArrayBindingPattern) {
             transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
         }
 
@@ -3058,6 +3106,10 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertJsx;
                 break;
 
+            case SyntaxKind.ForOfStatement:
+                // for-of might be ESNext if it has a rest destructuring
+                transformFlags |= TransformFlags.AssertESNext;
+                // FALLTHROUGH
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.TemplateHead:
             case SyntaxKind.TemplateMiddle:
@@ -3065,7 +3117,6 @@ namespace ts {
             case SyntaxKind.TemplateExpression:
             case SyntaxKind.TaggedTemplateExpression:
             case SyntaxKind.ShorthandPropertyAssignment:
-            case SyntaxKind.ForOfStatement:
             case SyntaxKind.StaticKeyword:
                 // These nodes are ES6 syntax.
                 transformFlags |= TransformFlags.AssertES2015;
@@ -3130,11 +3181,18 @@ namespace ts {
                 }
                 break;
 
-            case SyntaxKind.SpreadElementExpression:
-                // This node is ES6 syntax, but is handled by a containing node.
-                transformFlags |= TransformFlags.ContainsSpreadElementExpression;
+            case SyntaxKind.SpreadElement:
+            case SyntaxKind.SpreadAssignment:
+                // This node is ES6 or ES next syntax, but is handled by a containing node.
+                transformFlags |= TransformFlags.ContainsSpreadExpression;
                 break;
 
+            case SyntaxKind.BindingElement:
+                if ((node as BindingElement).dotDotDotToken) {
+                    // this node is ES2015 or ES next syntax, but is handled by a containing node.
+                    transformFlags |= TransformFlags.ContainsSpreadExpression;
+                }
+
             case SyntaxKind.SuperKeyword:
                 // This node is ES6 syntax.
                 transformFlags |= TransformFlags.AssertES2015;
@@ -3147,8 +3205,13 @@ namespace ts {
 
             case SyntaxKind.ObjectBindingPattern:
             case SyntaxKind.ArrayBindingPattern:
-                // These nodes are ES6 syntax.
-                transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+                // These nodes are ES2015 or ES Next syntax.
+                if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+                    transformFlags |= TransformFlags.AssertESNext | TransformFlags.ContainsBindingPattern;
+                }
+                else {
+                    transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
+                }
                 break;
 
             case SyntaxKind.Decorator:
@@ -3170,13 +3233,19 @@ namespace ts {
                     transformFlags |= TransformFlags.ContainsLexicalThis;
                 }
 
+                if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+                    // If an ObjectLiteralExpression contains a spread element, then it
+                    // is an ES next node.
+                    transformFlags |= TransformFlags.AssertESNext;
+                }
+
                 break;
 
             case SyntaxKind.ArrayLiteralExpression:
             case SyntaxKind.NewExpression:
                 excludeFlags = TransformFlags.ArrayLiteralOrCallOrNewExcludes;
-                if (subtreeFlags & TransformFlags.ContainsSpreadElementExpression) {
-                    // If the this node contains a SpreadElementExpression, then it is an ES6
+                if (subtreeFlags & TransformFlags.ContainsSpreadExpression) {
+                    // If the this node contains a SpreadExpression, then it is an ES6
                     // node.
                     transformFlags |= TransformFlags.AssertES2015;
                 }

src/compiler/checker.ts

@@ -335,6 +335,9 @@ namespace ts {
         });
 
         let jsxElementType: Type;
+        let _jsxNamespace: string;
+        let _jsxFactoryEntity: EntityName;
+
         /** Things we lazy load from the JSX namespace */
         const jsxTypes = createMap<Type>();
         const JsxNames = {
@@ -372,6 +375,22 @@ namespace ts {
 
         return checker;
 
+        function getJsxNamespace(): string {
+            if (_jsxNamespace === undefined) {
+                _jsxNamespace = "React";
+                if (compilerOptions.jsxFactory) {
+                    _jsxFactoryEntity = parseIsolatedEntityName(compilerOptions.jsxFactory, languageVersion);
+                    if (_jsxFactoryEntity) {
+                        _jsxNamespace = getFirstIdentifier(_jsxFactoryEntity).text;
+                    }
+                }
+                else if (compilerOptions.reactNamespace) {
+                    _jsxNamespace = compilerOptions.reactNamespace;
+                }
+            }
+            return _jsxNamespace;
+        }
+
         function getEmitResolver(sourceFile: SourceFile, cancellationToken: CancellationToken) {
             // Ensure we have all the type information in place for this file so that all the
             // emitter questions of this resolver will return the right information.
@@ -2501,6 +2520,13 @@ namespace ts {
                     writePunctuation(writer, SyntaxKind.OpenBraceToken);
                     writer.writeLine();
                     writer.increaseIndent();
+                    writeObjectLiteralType(resolved);
+                    writer.decreaseIndent();
+                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
+                    inObjectTypeLiteral = saveInObjectTypeLiteral;
+                }
+
+                function writeObjectLiteralType(resolved: ResolvedType) {
                     for (const signature of resolved.callSignatures) {
                         buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, /*kind*/ undefined, symbolStack);
                         writePunctuation(writer, SyntaxKind.SemicolonToken);
@@ -2533,9 +2559,6 @@ namespace ts {
                             writer.writeLine();
                         }
                     }
-                    writer.decreaseIndent();
-                    writePunctuation(writer, SyntaxKind.CloseBraceToken);
-                    inObjectTypeLiteral = saveInObjectTypeLiteral;
                 }
 
                 function writeMappedType(type: MappedType) {
@@ -3006,26 +3029,31 @@ namespace ts {
             return symbol && getSymbolLinks(symbol).type || getTypeForVariableLikeDeclaration(node, /*includeOptionality*/ false);
         }
 
-        function getTextOfPropertyName(name: PropertyName): string {
-            switch (name.kind) {
-                case SyntaxKind.Identifier:
-                    return (<Identifier>name).text;
-                case SyntaxKind.StringLiteral:
-                case SyntaxKind.NumericLiteral:
-                    return (<LiteralExpression>name).text;
-                case SyntaxKind.ComputedPropertyName:
-                    if (isStringOrNumericLiteral((<ComputedPropertyName>name).expression.kind)) {
-                        return (<LiteralExpression>(<ComputedPropertyName>name).expression).text;
-                    }
-            }
-
-            return undefined;
-        }
-
         function isComputedNonLiteralName(name: PropertyName): boolean {
             return name.kind === SyntaxKind.ComputedPropertyName && !isStringOrNumericLiteral((<ComputedPropertyName>name).expression.kind);
         }
 
+        function getRestType(source: Type, properties: PropertyName[], symbol: Symbol): Type {
+            Debug.assert(!!(source.flags & TypeFlags.Object), "Rest types only support object types right now.");
+            const members = createMap<Symbol>();
+            const names = createMap<true>();
+            for (const name of properties) {
+                names[getTextOfPropertyName(name)] = true;
+            }
+            for (const prop of getPropertiesOfType(source)) {
+                const inNamesToRemove = prop.name in names;
+                const isPrivate = getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected);
+                const isMethod = prop.flags & SymbolFlags.Method;
+                const isSetOnlyAccessor = prop.flags & SymbolFlags.SetAccessor && !(prop.flags & SymbolFlags.GetAccessor);
+                if (!inNamesToRemove && !isPrivate && !isMethod && !isSetOnlyAccessor) {
+                    members[prop.name] = prop;
+                }
+            }
+            const stringIndexInfo = getIndexInfoOfType(source, IndexKind.String);
+            const numberIndexInfo = getIndexInfoOfType(source, IndexKind.Number);
+            return createAnonymousType(symbol, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+        }
+
         /** Return the inferred type for a binding element */
         function getTypeForBindingElement(declaration: BindingElement): Type {
             const pattern = <BindingPattern>declaration.parent;
@@ -3046,26 +3074,41 @@ namespace ts {
 
             let type: Type;
             if (pattern.kind === SyntaxKind.ObjectBindingPattern) {
-                // Use explicitly specified property name ({ p: xxx } form), or otherwise the implied name ({ p } form)
-                const name = declaration.propertyName || <Identifier>declaration.name;
-                if (isComputedNonLiteralName(name)) {
-                    // computed properties with non-literal names are treated as 'any'
-                    return anyType;
-                }
-                if (declaration.initializer) {
-                    getContextualType(declaration.initializer);
+                if (declaration.dotDotDotToken) {
+                    if (!(parentType.flags & TypeFlags.Object)) {
+                        error(declaration, Diagnostics.Rest_types_may_only_be_created_from_object_types);
+                        return unknownType;
+                    }
+                    const literalMembers: PropertyName[] = [];
+                    for (const element of pattern.elements) {
+                        if (element.kind !== SyntaxKind.OmittedExpression && !(element as BindingElement).dotDotDotToken) {
+                            literalMembers.push(element.propertyName || element.name as Identifier);
+                        }
+                    }
+                    type = getRestType(parentType, literalMembers, declaration.symbol);
                 }
+                else {
+                    // Use explicitly specified property name ({ p: xxx } form), or otherwise the implied name ({ p } form)
+                    const name = declaration.propertyName || <Identifier>declaration.name;
+                    if (isComputedNonLiteralName(name)) {
+                        // computed properties with non-literal names are treated as 'any'
+                        return anyType;
+                    }
+                    if (declaration.initializer) {
+                        getContextualType(declaration.initializer);
+                    }
 
-                // Use type of the specified property, or otherwise, for a numeric name, the type of the numeric index signature,
-                // or otherwise the type of the string index signature.
-                const text = getTextOfPropertyName(name);
+                    // Use type of the specified property, or otherwise, for a numeric name, the type of the numeric index signature,
+                    // or otherwise the type of the string index signature.
+                    const text = getTextOfPropertyName(name);
 
-                type = getTypeOfPropertyOfType(parentType, text) ||
-                    isNumericLiteralName(text) && getIndexTypeOfType(parentType, IndexKind.Number) ||
-                    getIndexTypeOfType(parentType, IndexKind.String);
-                if (!type) {
-                    error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(parentType), declarationNameToString(name));
-                    return unknownType;
+                    type = getTypeOfPropertyOfType(parentType, text) ||
+                        isNumericLiteralName(text) && getIndexTypeOfType(parentType, IndexKind.Number) ||
+                        getIndexTypeOfType(parentType, IndexKind.String);
+                    if (!type) {
+                        error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(parentType), declarationNameToString(name));
+                        return unknownType;
+                    }
                 }
             }
             else {
@@ -3073,7 +3116,11 @@ namespace ts {
                 // present (aka the tuple element property). This call also checks that the parentType is in
                 // fact an iterable or array (depending on target language).
                 const elementType = checkIteratedTypeOrElementType(parentType, pattern, /*allowStringInput*/ false);
-                if (!declaration.dotDotDotToken) {
+                if (declaration.dotDotDotToken) {
+                    // Rest element has an array type with the same element type as the parent type
+                    type = createArrayType(elementType);
+                }
+                else {
                     // Use specific property type when parent is a tuple or numeric index type when parent is an array
                     const propName = "" + indexOf(pattern.elements, declaration);
                     type = isTupleLikeType(parentType)
@@ -3089,10 +3136,6 @@ namespace ts {
                         return unknownType;
                     }
                 }
-                else {
-                    // Rest element has an array type with the same element type as the parent type
-                    type = createArrayType(elementType);
-                }
             }
             // In strict null checking mode, if a default value of a non-undefined type is specified, remove
             // undefined from the final type.
@@ -3273,8 +3316,8 @@ namespace ts {
             let hasComputedProperties = false;
             forEach(pattern.elements, e => {
                 const name = e.propertyName || <Identifier>e.name;
-                if (isComputedNonLiteralName(name)) {
-                    // do not include computed properties in the implied type
+                if (isComputedNonLiteralName(name) || e.dotDotDotToken) {
+                    // do not include computed properties or rests in the implied type
                     hasComputedProperties = true;
                     return;
                 }
@@ -4371,6 +4414,11 @@ namespace ts {
                 getIntersectionType([info1.type, info2.type]), info1.isReadonly && info2.isReadonly);
         }
 
+        function unionSpreadIndexInfos(info1: IndexInfo, info2: IndexInfo): IndexInfo {
+            return info1 && info2 && createIndexInfo(
+                getUnionType([info1.type, info2.type]), info1.isReadonly || info2.isReadonly);
+        }
+
         function resolveIntersectionTypeMembers(type: IntersectionType) {
             // The members and properties collections are empty for intersection types. To get all properties of an
             // intersection type use getPropertiesOfType (only the language service uses this).
@@ -4582,7 +4630,9 @@ namespace ts {
 
         function getPropertiesOfType(type: Type): Symbol[] {
             type = getApparentType(type);
-            return type.flags & TypeFlags.UnionOrIntersection ? getPropertiesOfUnionOrIntersectionType(<UnionType>type) : getPropertiesOfObjectType(type);
+            return type.flags & TypeFlags.UnionOrIntersection ?
+                getPropertiesOfUnionOrIntersectionType(<UnionType>type) :
+                getPropertiesOfObjectType(type);
         }
 
         /**
@@ -4637,6 +4687,7 @@ namespace ts {
                         if (isReadonlySymbol(prop)) {
                             isReadonly = true;
                         }
+
                     }
                     else if (containingType.flags & TypeFlags.Union) {
                         isPartial = true;
@@ -5999,6 +6050,68 @@ namespace ts {
             return symbol ? getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(symbol) : undefined;
         }
 
+        /**
+         * Since the source of spread types are object literals, which are not binary,
+         * this function should be called in a left folding style, with left = previous result of getSpreadType
+         * and right = the new element to be spread.
+         */
+        function getSpreadType(left: Type, right: Type, isFromObjectLiteral: boolean): ResolvedType | IntrinsicType {
+            Debug.assert(!!(left.flags & (TypeFlags.Object | TypeFlags.Any)) && !!(right.flags & (TypeFlags.Object | TypeFlags.Any)), "Only object types may be spread.");
+            if (left.flags & TypeFlags.Any || right.flags & TypeFlags.Any) {
+                return anyType;
+            }
+            const members = createMap<Symbol>();
+            const skippedPrivateMembers = createMap<boolean>();
+            let stringIndexInfo: IndexInfo;
+            let numberIndexInfo: IndexInfo;
+            if (left === emptyObjectType) {
+                // for the first spread element, left === emptyObjectType, so take the right's string indexer
+                stringIndexInfo = getIndexInfoOfType(right, IndexKind.String);
+                numberIndexInfo = getIndexInfoOfType(right, IndexKind.Number);
+            }
+            else {
+                stringIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.String), getIndexInfoOfType(right, IndexKind.String));
+                numberIndexInfo = unionSpreadIndexInfos(getIndexInfoOfType(left, IndexKind.Number), getIndexInfoOfType(right, IndexKind.Number));
+            }
+
+            for (const rightProp of getPropertiesOfType(right)) {
+                // we approximate own properties as non-methods plus methods that are inside the object literal
+                const isOwnProperty = !(rightProp.flags & SymbolFlags.Method) || isFromObjectLiteral;
+                const isSetterWithoutGetter = rightProp.flags & SymbolFlags.SetAccessor && !(rightProp.flags & SymbolFlags.GetAccessor);
+                if (getDeclarationModifierFlagsFromSymbol(rightProp) & (ModifierFlags.Private | ModifierFlags.Protected)) {
+                    skippedPrivateMembers[rightProp.name] = true;
+                }
+                else if (isOwnProperty && !isSetterWithoutGetter) {
+                    members[rightProp.name] = rightProp;
+                }
+            }
+            for (const leftProp of getPropertiesOfType(left)) {
+                if (leftProp.flags & SymbolFlags.SetAccessor && !(leftProp.flags & SymbolFlags.GetAccessor)
+                    || leftProp.name in skippedPrivateMembers) {
+                    continue;
+                }
+                if (leftProp.name in members) {
+                    const rightProp = members[leftProp.name];
+                    const rightType = getTypeOfSymbol(rightProp);
+                    if (maybeTypeOfKind(rightType, TypeFlags.Undefined) || rightProp.flags & SymbolFlags.Optional) {
+                        const declarations: Declaration[] = concatenate(leftProp.declarations, rightProp.declarations);
+                        const flags = SymbolFlags.Property | SymbolFlags.Transient | (leftProp.flags & SymbolFlags.Optional);
+                        const result = <TransientSymbol>createSymbol(flags, leftProp.name);
+                        result.type = getUnionType([getTypeOfSymbol(leftProp), getTypeWithFacts(rightType, TypeFacts.NEUndefined)]);
+                        result.leftSpread = leftProp;
+                        result.rightSpread = rightProp;
+                        result.declarations = declarations;
+                        result.isReadonly = isReadonlySymbol(leftProp) || isReadonlySymbol(rightProp);
+                        members[leftProp.name] = result;
+                    }
+                }
+                else {
+                    members[leftProp.name] = leftProp;
+                }
+            }
+            return createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+        }
+
         function createLiteralType(flags: TypeFlags, text: string) {
             const type = <LiteralType>createType(flags);
             type.text = text;
@@ -8772,7 +8885,7 @@ namespace ts {
                 unknownType;
         }
 
-        function getTypeOfDestructuredSpreadElement(type: Type) {
+        function getTypeOfDestructuredSpreadExpression(type: Type) {
             return createArrayType(checkIteratedTypeOrElementType(type, /*errorNode*/ undefined, /*allowStringInput*/ false) || unknownType);
         }
 
@@ -8786,8 +8899,8 @@ namespace ts {
             return getTypeOfDestructuredArrayElement(getAssignedType(node), indexOf(node.elements, element));
         }
 
-        function getAssignedTypeOfSpreadElement(node: SpreadElementExpression): Type {
-            return getTypeOfDestructuredSpreadElement(getAssignedType(<ArrayLiteralExpression>node.parent));
+        function getAssignedTypeOfSpreadExpression(node: SpreadElement): Type {
+            return getTypeOfDestructuredSpreadExpression(getAssignedType(<ArrayLiteralExpression>node.parent));
         }
 
         function getAssignedTypeOfPropertyAssignment(node: PropertyAssignment | ShorthandPropertyAssignment): Type {
@@ -8811,8 +8924,8 @@ namespace ts {
                     return undefinedType;
                 case SyntaxKind.ArrayLiteralExpression:
                     return getAssignedTypeOfArrayLiteralElement(<ArrayLiteralExpression>parent, node);
-                case SyntaxKind.SpreadElementExpression:
-                    return getAssignedTypeOfSpreadElement(<SpreadElementExpression>parent);
+                case SyntaxKind.SpreadElement:
+                    return getAssignedTypeOfSpreadExpression(<SpreadElement>parent);
                 case SyntaxKind.PropertyAssignment:
                     return getAssignedTypeOfPropertyAssignment(<PropertyAssignment>parent);
                 case SyntaxKind.ShorthandPropertyAssignment:
@@ -8828,7 +8941,7 @@ namespace ts {
                 getTypeOfDestructuredProperty(parentType, node.propertyName || <Identifier>node.name) :
                 !node.dotDotDotToken ?
                     getTypeOfDestructuredArrayElement(parentType, indexOf(pattern.elements, node)) :
-                    getTypeOfDestructuredSpreadElement(parentType);
+                    getTypeOfDestructuredSpreadExpression(parentType);
             return getTypeWithDefault(type, node.initializer);
         }
 
@@ -10843,7 +10956,7 @@ namespace ts {
             return mapper && mapper.context;
         }
 
-        function checkSpreadElementExpression(node: SpreadElementExpression, contextualMapper?: TypeMapper): Type {
+        function checkSpreadExpression(node: SpreadElement, contextualMapper?: TypeMapper): Type {
             // It is usually not safe to call checkExpressionCached if we can be contextually typing.
             // You can tell that we are contextually typing because of the contextualMapper parameter.
             // While it is true that a spread element can have a contextual type, it does not do anything
@@ -10865,7 +10978,7 @@ namespace ts {
             const elementTypes: Type[] = [];
             const inDestructuringPattern = isAssignmentTarget(node);
             for (const e of elements) {
-                if (inDestructuringPattern && e.kind === SyntaxKind.SpreadElementExpression) {
+                if (inDestructuringPattern && e.kind === SyntaxKind.SpreadElement) {
                     // Given the following situation:
                     //    var c: {};
                     //    [...c] = ["", 0];
@@ -10878,7 +10991,7 @@ namespace ts {
                     // get the contextual element type from it. So we do something similar to
                     // getContextualTypeForElementExpression, which will crucially not error
                     // if there is no index type / iterated type.
-                    const restArrayType = checkExpression((<SpreadElementExpression>e).expression, contextualMapper);
+                    const restArrayType = checkExpression((<SpreadElement>e).expression, contextualMapper);
                     const restElementType = getIndexTypeOfType(restArrayType, IndexKind.Number) ||
                         (languageVersion >= ScriptTarget.ES2015 ? getElementTypeOfIterable(restArrayType, /*errorNode*/ undefined) : undefined);
                     if (restElementType) {
@@ -10889,7 +11002,7 @@ namespace ts {
                     const type = checkExpressionForMutableLocation(e, contextualMapper);
                     elementTypes.push(type);
                 }
-                hasSpreadElement = hasSpreadElement || e.kind === SyntaxKind.SpreadElementExpression;
+                hasSpreadElement = hasSpreadElement || e.kind === SyntaxKind.SpreadElement;
             }
             if (!hasSpreadElement) {
                 // If array literal is actually a destructuring pattern, mark it as an implied type. We do this such
@@ -11006,8 +11119,11 @@ namespace ts {
             // Grammar checking
             checkGrammarObjectLiteralExpression(node, inDestructuringPattern);
 
-            const propertiesTable = createMap<Symbol>();
-            const propertiesArray: Symbol[] = [];
+            let propertiesTable = createMap<Symbol>();
+            let propertiesArray: Symbol[] = [];
+            let spread: Type = emptyObjectType;
+            let propagatedFlags: TypeFlags = 0;
+
             const contextualType = getApparentTypeOfContextualType(node);
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
                 (contextualType.pattern.kind === SyntaxKind.ObjectBindingPattern || contextualType.pattern.kind === SyntaxKind.ObjectLiteralExpression);
@@ -11032,6 +11148,7 @@ namespace ts {
                         Debug.assert(memberDecl.kind === SyntaxKind.ShorthandPropertyAssignment);
                         type = checkExpressionForMutableLocation((<ShorthandPropertyAssignment>memberDecl).name, contextualMapper);
                     }
+
                     typeFlags |= type.flags;
                     const prop = <TransientSymbol>createSymbol(SymbolFlags.Property | SymbolFlags.Transient | member.flags, member.name);
                     if (inDestructuringPattern) {
@@ -11069,6 +11186,23 @@ namespace ts {
                     prop.target = member;
                     member = prop;
                 }
+                else if (memberDecl.kind === SyntaxKind.SpreadAssignment) {
+                    if (propertiesArray.length > 0) {
+                        spread = getSpreadType(spread, createObjectLiteralType(), /*isFromObjectLiteral*/ true);
+                        propertiesArray = [];
+                        propertiesTable = createMap<Symbol>();
+                        hasComputedStringProperty = false;
+                        hasComputedNumberProperty = false;
+                        typeFlags = 0;
+                    }
+                    const type = checkExpression((memberDecl as SpreadAssignment).expression);
+                    if (!(type.flags & (TypeFlags.Object | TypeFlags.Any))) {
+                        error(memberDecl, Diagnostics.Spread_types_may_only_be_created_from_object_types);
+                        return unknownType;
+                    }
+                    spread = getSpreadType(spread, type, /*isFromObjectLiteral*/ false);
+                    continue;
+                }
                 else {
                     // TypeScript 1.0 spec (April 2014)
                     // A get accessor declaration is processed in the same manner as
@@ -11108,20 +11242,36 @@ namespace ts {
                 }
             }
 
-            const stringIndexInfo = hasComputedStringProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.String) : undefined;
-            const numberIndexInfo = hasComputedNumberProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.Number) : undefined;
-            const result = createAnonymousType(node.symbol, propertiesTable, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
-            const freshObjectLiteralFlag = compilerOptions.suppressExcessPropertyErrors ? 0 : TypeFlags.FreshLiteral;
-            result.flags |= TypeFlags.ContainsObjectLiteral | freshObjectLiteralFlag | (typeFlags & TypeFlags.PropagatingFlags);
-            result.objectFlags |= ObjectFlags.ObjectLiteral;
-            if (patternWithComputedProperties) {
-                result.objectFlags |= ObjectFlags.ObjectLiteralPatternWithComputedProperties;
+            if (spread !== emptyObjectType) {
+                if (propertiesArray.length > 0) {
+                    spread = getSpreadType(spread, createObjectLiteralType(), /*isFromObjectLiteral*/ true);
+                }
+                spread.flags |= propagatedFlags;
+                spread.symbol = node.symbol;
+                return spread;
             }
-            if (inDestructuringPattern) {
-                result.pattern = node;
+
+            return createObjectLiteralType();
+
+            function createObjectLiteralType() {
+                const stringIndexInfo = hasComputedStringProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.String) : undefined;
+                const numberIndexInfo = hasComputedNumberProperty ? getObjectLiteralIndexInfo(node, propertiesArray, IndexKind.Number) : undefined;
+                const result = createAnonymousType(node.symbol, propertiesTable, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+                const freshObjectLiteralFlag = compilerOptions.suppressExcessPropertyErrors ? 0 : TypeFlags.FreshLiteral;
+                result.flags |= TypeFlags.ContainsObjectLiteral | freshObjectLiteralFlag | (typeFlags & TypeFlags.PropagatingFlags);
+                result.objectFlags |= ObjectFlags.ObjectLiteral;
+                if (patternWithComputedProperties) {
+                    result.objectFlags |= ObjectFlags.ObjectLiteralPatternWithComputedProperties;
+                }
+                if (inDestructuringPattern) {
+                    result.pattern = node;
+                }
+                if (!(result.flags & TypeFlags.Nullable)) {
+                    propagatedFlags |= (result.flags & TypeFlags.PropagatingFlags);
+                }
+                return result;
             }
-            return result;
-        }
+       }
 
         function checkJsxSelfClosingElement(node: JsxSelfClosingElement) {
             checkJsxOpeningLikeElement(node);
@@ -11538,10 +11688,10 @@ namespace ts {
         function checkJsxOpeningLikeElement(node: JsxOpeningLikeElement) {
             checkGrammarJsxElement(node);
             checkJsxPreconditions(node);
-            // The reactNamespace symbol should be marked as 'used' so we don't incorrectly elide its import. And if there
-            // is no reactNamespace symbol in scope when targeting React emit, we should issue an error.
+            // The reactNamespace/jsxFactory's root symbol should be marked as 'used' so we don't incorrectly elide its import. 
+            // And if there is no reactNamespace/jsxFactory's symbol in scope when targeting React emit, we should issue an error.
             const reactRefErr = compilerOptions.jsx === JsxEmit.React ? Diagnostics.Cannot_find_name_0 : undefined;
-            const reactNamespace = compilerOptions.reactNamespace ? compilerOptions.reactNamespace : "React";
+            const reactNamespace = getJsxNamespace();
             const reactSym = resolveName(node.tagName, reactNamespace, SymbolFlags.Value, reactRefErr, reactNamespace);
             if (reactSym) {
                 // Mark local symbol as referenced here because it might not have been marked
@@ -12020,7 +12170,7 @@ namespace ts {
         function getSpreadArgumentIndex(args: Expression[]): number {
             for (let i = 0; i < args.length; i++) {
                 const arg = args[i];
-                if (arg && arg.kind === SyntaxKind.SpreadElementExpression) {
+                if (arg && arg.kind === SyntaxKind.SpreadElement) {
                     return i;
                 }
             }
@@ -13986,7 +14136,7 @@ namespace ts {
                     error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(objectLiteralType), declarationNameToString(name));
                 }
             }
-            else {
+            else if (property.kind !== SyntaxKind.SpreadAssignment) {
                 error(property, Diagnostics.Property_assignment_expected);
             }
         }
@@ -14008,7 +14158,7 @@ namespace ts {
             const elements = node.elements;
             const element = elements[elementIndex];
             if (element.kind !== SyntaxKind.OmittedExpression) {
-                if (element.kind !== SyntaxKind.SpreadElementExpression) {
+                if (element.kind !== SyntaxKind.SpreadElement) {
                     const propName = "" + elementIndex;
                     const type = isTypeAny(sourceType)
                         ? sourceType
@@ -14032,10 +14182,10 @@ namespace ts {
                 }
                 else {
                     if (elementIndex < elements.length - 1) {
-                        error(element, Diagnostics.A_rest_element_must_be_last_in_an_array_destructuring_pattern);
+                        error(element, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
                     }
                     else {
-                        const restExpression = (<SpreadElementExpression>element).expression;
+                        const restExpression = (<SpreadElement>element).expression;
                         if (restExpression.kind === SyntaxKind.BinaryExpression && (<BinaryExpression>restExpression).operatorToken.kind === SyntaxKind.EqualsToken) {
                             error((<BinaryExpression>restExpression).operatorToken, Diagnostics.A_rest_element_cannot_have_an_initializer);
                         }
@@ -14668,8 +14818,8 @@ namespace ts {
                     return checkBinaryExpression(<BinaryExpression>node, contextualMapper);
                 case SyntaxKind.ConditionalExpression:
                     return checkConditionalExpression(<ConditionalExpression>node, contextualMapper);
-                case SyntaxKind.SpreadElementExpression:
-                    return checkSpreadElementExpression(<SpreadElementExpression>node, contextualMapper);
+                case SyntaxKind.SpreadElement:
+                    return checkSpreadExpression(<SpreadElement>node, contextualMapper);
                 case SyntaxKind.OmittedExpression:
                     return undefinedWideningType;
                 case SyntaxKind.YieldExpression:
@@ -17190,6 +17340,7 @@ namespace ts {
             let hasDuplicateDefaultClause = false;
 
             const expressionType = checkExpression(node.expression);
+            const expressionIsLiteral = isLiteralType(expressionType);
             forEach(node.caseBlock.clauses, clause => {
                 // Grammar check for duplicate default clauses, skip if we already report duplicate default clause
                 if (clause.kind === SyntaxKind.DefaultClause && !hasDuplicateDefaultClause) {
@@ -17210,10 +17361,16 @@ namespace ts {
                     // TypeScript 1.0 spec (April 2014): 5.9
                     // In a 'switch' statement, each 'case' expression must be of a type that is comparable
                     // to or from the type of the 'switch' expression.
-                    const caseType = checkExpression(caseClause.expression);
-                    if (!isTypeEqualityComparableTo(expressionType, caseType)) {
+                    let caseType = checkExpression(caseClause.expression);
+                    const caseIsLiteral = isLiteralType(caseType);
+                    let comparedExpressionType = expressionType;
+                    if (!caseIsLiteral || !expressionIsLiteral) {
+                        caseType = caseIsLiteral ? getBaseTypeOfLiteralType(caseType) : caseType;
+                        comparedExpressionType = getBaseTypeOfLiteralType(expressionType);
+                    }
+                    if (!isTypeEqualityComparableTo(comparedExpressionType, caseType)) {
                         // expressionType is not comparable to caseType, try the reversed check and report errors if it fails
-                        checkTypeComparableTo(caseType, expressionType, caseClause.expression, /*headMessage*/ undefined);
+                        checkTypeComparableTo(caseType, comparedExpressionType, caseClause.expression, /*headMessage*/ undefined);
                     }
                 }
                 forEach(clause.statements, checkSourceElement);
@@ -19320,6 +19477,10 @@ namespace ts {
                 return symbols;
             }
             else if (symbol.flags & SymbolFlags.Transient) {
+                if ((symbol as SymbolLinks).leftSpread) {
+                    const links = symbol as SymbolLinks;
+                    return [links.leftSpread, links.rightSpread];
+                }
                 let target: Symbol;
                 let next = symbol;
                 while (next = getSymbolLinks(next).target) {
@@ -19808,7 +19969,8 @@ namespace ts {
                 getTypeReferenceDirectivesForEntityName,
                 getTypeReferenceDirectivesForSymbol,
                 isLiteralConstDeclaration,
-                writeLiteralConstValue
+                writeLiteralConstValue,
+                getJsxFactoryEntity: () => _jsxFactoryEntity
             };
 
             // defined here to avoid outer scope pollution
@@ -20020,7 +20182,7 @@ namespace ts {
                     if (requestedExternalEmitHelpers & NodeFlags.HasClassExtends && languageVersion < ScriptTarget.ES2015) {
                         verifyHelperSymbol(exports, "__extends", SymbolFlags.Value);
                     }
-                    if (requestedExternalEmitHelpers & NodeFlags.HasJsxSpreadAttributes && compilerOptions.jsx !== JsxEmit.Preserve) {
+                    if (requestedExternalEmitHelpers & NodeFlags.HasSpreadAttribute && compilerOptions.jsx !== JsxEmit.Preserve) {
                         verifyHelperSymbol(exports, "__assign", SymbolFlags.Value);
                     }
                     if (requestedExternalEmitHelpers & NodeFlags.HasDecorators) {
@@ -20583,7 +20745,6 @@ namespace ts {
                     checkGrammarHeritageClause(heritageClause);
                 }
             }
-
             return false;
         }
 
@@ -20631,6 +20792,9 @@ namespace ts {
             const GetOrSetAccessor = GetAccessor | SetAccessor;
 
             for (const prop of node.properties) {
+                if (prop.kind === SyntaxKind.SpreadAssignment) {
+                    continue;
+                }
                 const name = prop.name;
                 if (name.kind === SyntaxKind.ComputedPropertyName) {
                     // If the name is not a ComputedPropertyName, the grammar checking will skip it
@@ -20934,7 +21098,7 @@ namespace ts {
             if (node.dotDotDotToken) {
                 const elements = (<BindingPattern>node.parent).elements;
                 if (node !== lastOrUndefined(elements)) {
-                    return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_an_array_destructuring_pattern);
+                    return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
                 }
 
                 if (node.name.kind === SyntaxKind.ArrayBindingPattern || node.name.kind === SyntaxKind.ObjectBindingPattern) {
@@ -20942,7 +21106,7 @@ namespace ts {
                 }
 
                 if (node.initializer) {
-                    // Error on equals token which immediate precedes the initializer
+                    // Error on equals token which immediately precedes the initializer
                     return grammarErrorAtPos(getSourceFileOfNode(node), node.initializer.pos - 1, 1, Diagnostics.A_rest_element_cannot_have_an_initializer);
                 }
             }

src/compiler/commandLineParser.ts

@@ -77,6 +77,11 @@ namespace ts {
             type: "string",
             description: Diagnostics.Specify_the_object_invoked_for_createElement_and_spread_when_targeting_react_JSX_emit
         },
+        {
+            name: "jsxFactory",
+            type: "string",
+            description: Diagnostics.Specify_the_JSX_factory_function_to_use_when_targeting_react_JSX_emit_e_g_React_createElement_or_h
+        },
         {
             name: "listFiles",
             type: "boolean",
@@ -265,6 +270,7 @@ namespace ts {
                 "es2015": ScriptTarget.ES2015,
                 "es2016": ScriptTarget.ES2016,
                 "es2017": ScriptTarget.ES2017,
+                "esnext": ScriptTarget.ESNext,
             }),
             description: Diagnostics.Specify_ECMAScript_target_version_Colon_ES3_default_ES5_or_ES2015,
             paramType: Diagnostics.VERSION,

src/compiler/diagnosticMessages.json

@@ -1455,7 +1455,7 @@
         "category": "Error",
         "code": 2461
     },
-    "A rest element must be last in an array destructuring pattern": {
+    "A rest element must be last in a destructuring pattern": {
         "category": "Error",
         "code": 2462
     },
@@ -1983,6 +1983,14 @@
         "category": "Error",
         "code": 2697
     },
+    "Spread types may only be created from object types.": {
+        "category": "Error",
+        "code": 2698
+    },
+    "Rest types may only be created from object types.": {
+        "category": "Error",
+        "code": 2700
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
@@ -2381,6 +2389,10 @@
         "category": "Error",
         "code": 5066
     },
+    "Invalid value for 'jsxFactory'. '{0}' is not a valid identifier or qualified-name.": {
+        "category": "Error",
+        "code": 5067
+    },
     "Concatenate and emit output to single file.": {
         "category": "Message",
         "code": 6001
@@ -2897,6 +2909,10 @@
         "category": "Message",
         "code": 6145
     },
+    "Specify the JSX factory function to use when targeting 'react' JSX emit, e.g. 'React.createElement' or 'h'.": {
+        "category": "Message",
+        "code": 6146
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005

src/compiler/emitter.ts

@@ -42,6 +42,14 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
     return t;
 };`;
 
+        const restHelper = `
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};`;
+
         // emit output for the __decorate helper function
         const decorateHelper = `
 var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
@@ -226,6 +234,7 @@ const _super = (function (geti, seti) {
         let currentFileIdentifiers: Map<string>;
         let extendsEmitted: boolean;
         let assignEmitted: boolean;
+        let restEmitted: boolean;
         let decorateEmitted: boolean;
         let paramEmitted: boolean;
         let awaiterEmitted: boolean;
@@ -732,6 +741,8 @@ const _super = (function (geti, seti) {
                     return emitPropertyAssignment(<PropertyAssignment>node);
                 case SyntaxKind.ShorthandPropertyAssignment:
                     return emitShorthandPropertyAssignment(<ShorthandPropertyAssignment>node);
+                case SyntaxKind.SpreadAssignment:
+                    return emitSpreadAssignment(node as SpreadAssignment);
 
                 // Enum
                 case SyntaxKind.EnumMember:
@@ -822,8 +833,8 @@ const _super = (function (geti, seti) {
                     return emitTemplateExpression(<TemplateExpression>node);
                 case SyntaxKind.YieldExpression:
                     return emitYieldExpression(<YieldExpression>node);
-                case SyntaxKind.SpreadElementExpression:
-                    return emitSpreadElementExpression(<SpreadElementExpression>node);
+                case SyntaxKind.SpreadElement:
+                    return emitSpreadExpression(<SpreadElement>node);
                 case SyntaxKind.ClassExpression:
                     return emitClassExpression(<ClassExpression>node);
                 case SyntaxKind.OmittedExpression:
@@ -1374,7 +1385,7 @@ const _super = (function (geti, seti) {
             emitExpressionWithPrefix(" ", node.expression);
         }
 
-        function emitSpreadElementExpression(node: SpreadElementExpression) {
+        function emitSpreadExpression(node: SpreadElement) {
             write("...");
             emitExpression(node.expression);
         }
@@ -2102,6 +2113,13 @@ const _super = (function (geti, seti) {
             }
         }
 
+        function emitSpreadAssignment(node: SpreadAssignment) {
+            if (node.expression) {
+                write("...");
+                emitExpression(node.expression);
+            }
+        }
+
         //
         // Enum
         //
@@ -2205,11 +2223,19 @@ const _super = (function (geti, seti) {
                 helpersEmitted = true;
             }
 
-            if (compilerOptions.jsx !== JsxEmit.Preserve && !assignEmitted && (node.flags & NodeFlags.HasJsxSpreadAttributes)) {
+            if ((languageVersion < ScriptTarget.ESNext || currentSourceFile.scriptKind === ScriptKind.JSX || currentSourceFile.scriptKind === ScriptKind.TSX) &&
+                compilerOptions.jsx !== JsxEmit.Preserve &&
+                !assignEmitted &&
+                node.flags & NodeFlags.HasSpreadAttribute) {
                 writeLines(assignHelper);
                 assignEmitted = true;
             }
 
+            if (languageVersion < ScriptTarget.ESNext && !restEmitted && node.flags & NodeFlags.HasRestAttribute) {
+                writeLines(restHelper);
+                restEmitted = true;
+            }
+
             if (!decorateEmitted && node.flags & NodeFlags.HasDecorators) {
                 writeLines(decorateHelper);
                 if (compilerOptions.emitDecoratorMetadata) {

src/compiler/factory.ts

@@ -692,12 +692,12 @@ namespace ts {
     }
 
     export function createSpread(expression: Expression, location?: TextRange) {
-        const node = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression, location);
+        const node = <SpreadElement>createNode(SyntaxKind.SpreadElement, location);
         node.expression = parenthesizeExpressionForList(expression);
         return node;
     }
 
-    export function updateSpread(node: SpreadElementExpression, expression: Expression) {
+    export function updateSpread(node: SpreadElement, expression: Expression) {
         if (node.expression !== expression) {
             return updateNode(createSpread(expression, node), node);
         }
@@ -1399,14 +1399,27 @@ namespace ts {
         return node;
     }
 
-    export function updateShorthandPropertyAssignment(node: ShorthandPropertyAssignment, name: Identifier, objectAssignmentInitializer: Expression) {
+    export function createSpreadAssignment(expression: Expression, location?: TextRange) {
+        const node = <SpreadAssignment>createNode(SyntaxKind.SpreadAssignment, location);
+        node.expression = expression !== undefined ? parenthesizeExpressionForList(expression) : undefined;
+        return node;
+    }
+
+   export function updateShorthandPropertyAssignment(node: ShorthandPropertyAssignment, name: Identifier, objectAssignmentInitializer: Expression) {
         if (node.name !== name || node.objectAssignmentInitializer !== objectAssignmentInitializer) {
             return updateNode(createShorthandPropertyAssignment(name, objectAssignmentInitializer, node), node);
         }
         return node;
     }
 
-    // Top-level nodes
+    export function updateSpreadAssignment(node: SpreadAssignment, expression: Expression) {
+        if (node.expression !== expression) {
+            return updateNode(createSpreadAssignment(expression, node), node);
+        }
+        return node;
+    }
+
+   // Top-level nodes
 
     export function updateSourceFileNode(node: SourceFile, statements: Statement[]) {
         if (node.statements !== statements) {
@@ -1628,7 +1641,34 @@ namespace ts {
         return react;
     }
 
-    export function createReactCreateElement(reactNamespace: string, tagName: Expression, props: Expression, children: Expression[], parentElement: JsxOpeningLikeElement, location: TextRange): LeftHandSideExpression {
+    function createJsxFactoryExpressionFromEntityName(jsxFactory: EntityName, parent: JsxOpeningLikeElement): Expression {
+        if (isQualifiedName(jsxFactory)) {
+            return createPropertyAccess(
+                createJsxFactoryExpressionFromEntityName(
+                    jsxFactory.left,
+                    parent
+                ),
+                setEmitFlags(
+                    getMutableClone(jsxFactory.right),
+                    EmitFlags.NoSourceMap
+                )
+            );
+        }
+        else {
+            return createReactNamespace(jsxFactory.text, parent);
+        }
+    }
+
+    function createJsxFactoryExpression(jsxFactoryEntity: EntityName, reactNamespace: string, parent: JsxOpeningLikeElement): Expression {
+        return jsxFactoryEntity ?
+            createJsxFactoryExpressionFromEntityName(jsxFactoryEntity, parent) :
+            createPropertyAccess(
+                createReactNamespace(reactNamespace, parent),
+                "createElement"
+            );
+    }
+
+    export function createExpressionForJsxElement(jsxFactoryEntity: EntityName, reactNamespace: string, tagName: Expression, props: Expression, children: Expression[], parentElement: JsxOpeningLikeElement, location: TextRange): LeftHandSideExpression {
         const argumentsList = [tagName];
         if (props) {
             argumentsList.push(props);
@@ -1651,10 +1691,7 @@ namespace ts {
         }
 
         return createCall(
-            createPropertyAccess(
-                createReactNamespace(reactNamespace, parentElement),
-                "createElement"
-            ),
+            createJsxFactoryExpression(jsxFactoryEntity, reactNamespace, parentElement),
             /*typeArguments*/ undefined,
             argumentsList,
             location
@@ -3055,4 +3092,538 @@ namespace ts {
     function tryGetModuleNameFromDeclaration(declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration, host: EmitHost, resolver: EmitResolver, compilerOptions: CompilerOptions) {
         return tryGetModuleNameFromFile(resolver.getExternalModuleFileFromDeclaration(declaration), host, compilerOptions);
     }
+
+    /**
+     * Transforms the body of a function-like node.
+     *
+     * @param node A function-like node.
+     */
+    export function transformFunctionBody(node: FunctionLikeDeclaration,
+                                          visitor: (node: Node) => VisitResult<Node>,
+                                          currentSourceFile: SourceFile,
+                                          context: TransformationContext,
+                                          enableSubstitutionsForCapturedThis: () => void,
+                                          convertObjectRest?: boolean) {
+        let multiLine = false; // indicates whether the block *must* be emitted as multiple lines
+        let singleLine = false; // indicates whether the block *may* be emitted as a single line
+        let statementsLocation: TextRange;
+        let closeBraceLocation: TextRange;
+
+        const statements: Statement[] = [];
+        const body = node.body;
+        let statementOffset: number;
+
+        context.startLexicalEnvironment();
+        if (isBlock(body)) {
+            // ensureUseStrict is false because no new prologue-directive should be added.
+            // addPrologueDirectives will simply put already-existing directives at the beginning of the target statement-array
+            statementOffset = addPrologueDirectives(statements, body.statements, /*ensureUseStrict*/ false, visitor);
+        }
+
+        addCaptureThisForNodeIfNeeded(statements, node, enableSubstitutionsForCapturedThis);
+        addDefaultValueAssignmentsIfNeeded(statements, node, visitor, convertObjectRest);
+        addRestParameterIfNeeded(statements, node, /*inConstructorWithSynthesizedSuper*/ false);
+
+        // If we added any generated statements, this must be a multi-line block.
+        if (!multiLine && statements.length > 0) {
+            multiLine = true;
+        }
+
+        if (isBlock(body)) {
+            statementsLocation = body.statements;
+            addRange(statements, visitNodes(body.statements, visitor, isStatement, statementOffset));
+
+            // If the original body was a multi-line block, this must be a multi-line block.
+            if (!multiLine && body.multiLine) {
+                multiLine = true;
+            }
+        }
+        else {
+            Debug.assert(node.kind === SyntaxKind.ArrowFunction);
+
+            // To align with the old emitter, we use a synthetic end position on the location
+            // for the statement list we synthesize when we down-level an arrow function with
+            // an expression function body. This prevents both comments and source maps from
+            // being emitted for the end position only.
+            statementsLocation = moveRangeEnd(body, -1);
+
+            const equalsGreaterThanToken = (<ArrowFunction>node).equalsGreaterThanToken;
+            if (!nodeIsSynthesized(equalsGreaterThanToken) && !nodeIsSynthesized(body)) {
+                if (rangeEndIsOnSameLineAsRangeStart(equalsGreaterThanToken, body, currentSourceFile)) {
+                    singleLine = true;
+                }
+                else {
+                    multiLine = true;
+                }
+            }
+
+            const expression = visitNode(body, visitor, isExpression);
+            const returnStatement = createReturn(expression, /*location*/ body);
+            setEmitFlags(returnStatement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTrailingComments);
+            statements.push(returnStatement);
+
+            // To align with the source map emit for the old emitter, we set a custom
+            // source map location for the close brace.
+            closeBraceLocation = body;
+        }
+
+        const lexicalEnvironment = context.endLexicalEnvironment();
+        addRange(statements, lexicalEnvironment);
+
+        // If we added any final generated statements, this must be a multi-line block
+        if (!multiLine && lexicalEnvironment && lexicalEnvironment.length) {
+            multiLine = true;
+        }
+
+        const block = createBlock(createNodeArray(statements, statementsLocation), node.body, multiLine);
+        if (!multiLine && singleLine) {
+            setEmitFlags(block, EmitFlags.SingleLine);
+        }
+
+        if (closeBraceLocation) {
+            setTokenSourceMapRange(block, SyntaxKind.CloseBraceToken, closeBraceLocation);
+        }
+
+        setOriginalNode(block, node.body);
+        return block;
+    }
+
+    /**
+     * Adds a statement to capture the `this` of a function declaration if it is needed.
+     *
+     * @param statements The statements for the new function body.
+     * @param node A node.
+     */
+    export function addCaptureThisForNodeIfNeeded(statements: Statement[], node: Node, enableSubstitutionsForCapturedThis: () => void): void {
+        if (node.transformFlags & TransformFlags.ContainsCapturedLexicalThis && node.kind !== SyntaxKind.ArrowFunction) {
+            captureThisForNode(statements, node, createThis(), enableSubstitutionsForCapturedThis);
+        }
+    }
+
+    export function captureThisForNode(statements: Statement[], node: Node, initializer: Expression | undefined, enableSubstitutionsForCapturedThis?: () => void, originalStatement?: Statement): void {
+        enableSubstitutionsForCapturedThis();
+        const captureThisStatement = createVariableStatement(
+            /*modifiers*/ undefined,
+            createVariableDeclarationList([
+                createVariableDeclaration(
+                    "_this",
+                    /*type*/ undefined,
+                    initializer
+                )
+            ]),
+            originalStatement
+        );
+
+        setEmitFlags(captureThisStatement, EmitFlags.NoComments | EmitFlags.CustomPrologue);
+        setSourceMapRange(captureThisStatement, node);
+        statements.push(captureThisStatement);
+    }
+
+    /**
+     * Gets a value indicating whether we need to add default value assignments for a
+     * function-like node.
+     *
+     * @param node A function-like node.
+     */
+    function shouldAddDefaultValueAssignments(node: FunctionLikeDeclaration): boolean {
+        return (node.transformFlags & TransformFlags.ContainsDefaultValueAssignments) !== 0;
+    }
+
+    /**
+     * Adds statements to the body of a function-like node if it contains parameters with
+     * binding patterns or initializers.
+     *
+     * @param statements The statements for the new function body.
+     * @param node A function-like node.
+     */
+    export function addDefaultValueAssignmentsIfNeeded(statements: Statement[],
+                                                       node: FunctionLikeDeclaration,
+                                                       visitor: (node: Node) => VisitResult<Node>,
+                                                       convertObjectRest: boolean): void {
+        if (!shouldAddDefaultValueAssignments(node)) {
+            return;
+        }
+
+        for (const parameter of node.parameters) {
+            const { name, initializer, dotDotDotToken } = parameter;
+
+            // A rest parameter cannot have a binding pattern or an initializer,
+            // so let's just ignore it.
+            if (dotDotDotToken) {
+                continue;
+            }
+
+            if (isBindingPattern(name)) {
+                addDefaultValueAssignmentForBindingPattern(statements, parameter, name, initializer, visitor, convertObjectRest);
+            }
+            else if (initializer) {
+                addDefaultValueAssignmentForInitializer(statements, parameter, name, initializer, visitor);
+            }
+        }
+    }
+
+    /**
+     * Adds statements to the body of a function-like node for parameters with binding patterns
+     *
+     * @param statements The statements for the new function body.
+     * @param parameter The parameter for the function.
+     * @param name The name of the parameter.
+     * @param initializer The initializer for the parameter.
+     */
+    function addDefaultValueAssignmentForBindingPattern(statements: Statement[],
+                                                        parameter: ParameterDeclaration,
+                                                        name: BindingPattern, initializer: Expression,
+                                                        visitor: (node: Node) => VisitResult<Node>,
+                                                        convertObjectRest: boolean): void {
+        const temp = getGeneratedNameForNode(parameter);
+
+        // In cases where a binding pattern is simply '[]' or '{}',
+        // we usually don't want to emit a var declaration; however, in the presence
+        // of an initializer, we must emit that expression to preserve side effects.
+        if (name.elements.length > 0) {
+            statements.push(
+                setEmitFlags(
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        createVariableDeclarationList(
+                            flattenParameterDestructuring(parameter, temp, visitor, convertObjectRest)
+                        )
+                    ),
+                    EmitFlags.CustomPrologue
+                )
+            );
+        }
+        else if (initializer) {
+            statements.push(
+                setEmitFlags(
+                    createStatement(
+                        createAssignment(
+                            temp,
+                            visitNode(initializer, visitor, isExpression)
+                        )
+                    ),
+                    EmitFlags.CustomPrologue
+                )
+            );
+        }
+    }
+
+    /**
+     * Adds statements to the body of a function-like node for parameters with initializers.
+     *
+     * @param statements The statements for the new function body.
+     * @param parameter The parameter for the function.
+     * @param name The name of the parameter.
+     * @param initializer The initializer for the parameter.
+     */
+    function addDefaultValueAssignmentForInitializer(statements: Statement[],
+                                                     parameter: ParameterDeclaration,
+                                                     name: Identifier,
+                                                     initializer: Expression,
+                                                     visitor: (node: Node) => VisitResult<Node>): void {
+        initializer = visitNode(initializer, visitor, isExpression);
+        const statement = createIf(
+            createStrictEquality(
+                getSynthesizedClone(name),
+                createVoidZero()
+            ),
+            setEmitFlags(
+                createBlock([
+                    createStatement(
+                        createAssignment(
+                            setEmitFlags(getMutableClone(name), EmitFlags.NoSourceMap),
+                            setEmitFlags(initializer, EmitFlags.NoSourceMap | getEmitFlags(initializer)),
+                            /*location*/ parameter
+                        )
+                    )
+                ], /*location*/ parameter),
+                EmitFlags.SingleLine | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTokenSourceMaps
+            ),
+            /*elseStatement*/ undefined,
+            /*location*/ parameter
+        );
+        statement.startsOnNewLine = true;
+        setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.CustomPrologue);
+        statements.push(statement);
+    }
+
+    /**
+     * Gets a value indicating whether we need to add statements to handle a rest parameter.
+     *
+     * @param node A ParameterDeclaration node.
+     * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
+     *                                          part of a constructor declaration with a
+     *                                          synthesized call to `super`
+     */
+    function shouldAddRestParameter(node: ParameterDeclaration, inConstructorWithSynthesizedSuper: boolean) {
+        return node && node.dotDotDotToken && node.name.kind === SyntaxKind.Identifier && !inConstructorWithSynthesizedSuper;
+    }
+
+    /**
+     * Adds statements to the body of a function-like node if it contains a rest parameter.
+     *
+     * @param statements The statements for the new function body.
+     * @param node A function-like node.
+     * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
+     *                                          part of a constructor declaration with a
+     *                                          synthesized call to `super`
+     */
+    export function addRestParameterIfNeeded(statements: Statement[], node: FunctionLikeDeclaration, inConstructorWithSynthesizedSuper: boolean): void {
+        const parameter = lastOrUndefined(node.parameters);
+        if (!shouldAddRestParameter(parameter, inConstructorWithSynthesizedSuper)) {
+            return;
+        }
+
+        // `declarationName` is the name of the local declaration for the parameter.
+        const declarationName = getMutableClone(<Identifier>parameter.name);
+        setEmitFlags(declarationName, EmitFlags.NoSourceMap);
+
+        // `expressionName` is the name of the parameter used in expressions.
+        const expressionName = getSynthesizedClone(<Identifier>parameter.name);
+        const restIndex = node.parameters.length - 1;
+        const temp = createLoopVariable();
+
+        // var param = [];
+        statements.push(
+            setEmitFlags(
+                createVariableStatement(
+                    /*modifiers*/ undefined,
+                    createVariableDeclarationList([
+                        createVariableDeclaration(
+                            declarationName,
+                            /*type*/ undefined,
+                            createArrayLiteral([])
+                        )
+                    ]),
+                    /*location*/ parameter
+                ),
+                EmitFlags.CustomPrologue
+            )
+        );
+
+        // for (var _i = restIndex; _i < arguments.length; _i++) {
+        //   param[_i - restIndex] = arguments[_i];
+        // }
+        const forStatement = createFor(
+            createVariableDeclarationList([
+                createVariableDeclaration(temp, /*type*/ undefined, createLiteral(restIndex))
+            ], /*location*/ parameter),
+            createLessThan(
+                temp,
+                createPropertyAccess(createIdentifier("arguments"), "length"),
+                /*location*/ parameter
+            ),
+            createPostfixIncrement(temp, /*location*/ parameter),
+            createBlock([
+                startOnNewLine(
+                    createStatement(
+                        createAssignment(
+                            createElementAccess(
+                                expressionName,
+                                createSubtract(temp, createLiteral(restIndex))
+                            ),
+                            createElementAccess(createIdentifier("arguments"), temp)
+                        ),
+                        /*location*/ parameter
+                    )
+                )
+            ])
+        );
+
+        setEmitFlags(forStatement, EmitFlags.CustomPrologue);
+        startOnNewLine(forStatement);
+        statements.push(forStatement);
+    }
+
+
+
+
+    export function convertForOf(node: ForOfStatement, convertedLoopBodyStatements: Statement[],
+                                 visitor: (node: Node) => VisitResult<Node>,
+                                 enableSubstitutionsForBlockScopedBindings: () => void,
+                                 context: TransformationContext,
+                                 convertObjectRest?: boolean): ForStatement | ForOfStatement {
+        // The following ES6 code:
+        //
+        //    for (let v of expr) { }
+        //
+        // should be emitted as
+        //
+        //    for (var _i = 0, _a = expr; _i < _a.length; _i++) {
+        //        var v = _a[_i];
+        //    }
+        //
+        // where _a and _i are temps emitted to capture the RHS and the counter,
+        // respectively.
+        // When the left hand side is an expression instead of a let declaration,
+        // the "let v" is not emitted.
+        // When the left hand side is a let/const, the v is renamed if there is
+        // another v in scope.
+        // Note that all assignments to the LHS are emitted in the body, including
+        // all destructuring.
+        // Note also that because an extra statement is needed to assign to the LHS,
+        // for-of bodies are always emitted as blocks.
+
+        const expression = visitNode(node.expression, visitor, isExpression);
+        const initializer = node.initializer;
+        const statements: Statement[] = [];
+
+        // In the case where the user wrote an identifier as the RHS, like this:
+        //
+        //     for (let v of arr) { }
+        //
+        // we don't want to emit a temporary variable for the RHS, just use it directly.
+        const counter = convertObjectRest ? undefined : createLoopVariable();
+        const rhsReference = expression.kind === SyntaxKind.Identifier
+            ? createUniqueName((<Identifier>expression).text)
+            : createTempVariable(/*recordTempVariable*/ undefined);
+        const elementAccess = convertObjectRest ? rhsReference : createElementAccess(rhsReference, counter);
+
+        // Initialize LHS
+        // var v = _a[_i];
+        if (isVariableDeclarationList(initializer)) {
+            if (initializer.flags & NodeFlags.BlockScoped) {
+                enableSubstitutionsForBlockScopedBindings();
+            }
+
+            const firstOriginalDeclaration = firstOrUndefined(initializer.declarations);
+            if (firstOriginalDeclaration && isBindingPattern(firstOriginalDeclaration.name)) {
+                // This works whether the declaration is a var, let, or const.
+                // It will use rhsIterationValue _a[_i] as the initializer.
+                const declarations = flattenVariableDestructuring(
+                    firstOriginalDeclaration,
+                    elementAccess,
+                    visitor,
+                    /*recordTempVariable*/ undefined,
+                    convertObjectRest
+                );
+
+                const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer);
+                setOriginalNode(declarationList, initializer);
+
+                // Adjust the source map range for the first declaration to align with the old
+                // emitter.
+                const firstDeclaration = declarations[0];
+                const lastDeclaration = lastOrUndefined(declarations);
+                setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end));
+
+                statements.push(
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        declarationList
+                    )
+                );
+            }
+            else {
+                // The following call does not include the initializer, so we have
+                // to emit it separately.
+                statements.push(
+                    createVariableStatement(
+                        /*modifiers*/ undefined,
+                        setOriginalNode(
+                            createVariableDeclarationList([
+                                createVariableDeclaration(
+                                    firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined),
+                                    /*type*/ undefined,
+                                    createElementAccess(rhsReference, counter)
+                                )
+                            ], /*location*/ moveRangePos(initializer, -1)),
+                            initializer
+                        ),
+                        /*location*/ moveRangeEnd(initializer, -1)
+                    )
+                );
+            }
+        }
+        else {
+            // Initializer is an expression. Emit the expression in the body, so that it's
+            // evaluated on every iteration.
+            const assignment = createAssignment(initializer, elementAccess);
+            if (isDestructuringAssignment(assignment)) {
+                // This is a destructuring pattern, so we flatten the destructuring instead.
+                statements.push(
+                    createStatement(
+                        flattenDestructuringAssignment(
+                            context,
+                            assignment,
+                            /*needsValue*/ false,
+                            context.hoistVariableDeclaration,
+                            visitor,
+                            convertObjectRest
+                        )
+                    )
+                );
+            }
+            else {
+                // Currently there is not way to check that assignment is binary expression of destructing assignment
+                // so we have to cast never type to binaryExpression
+                (<BinaryExpression>assignment).end = initializer.end;
+                statements.push(createStatement(assignment, /*location*/ moveRangeEnd(initializer, -1)));
+            }
+        }
+
+        let bodyLocation: TextRange;
+        let statementsLocation: TextRange;
+        if (convertedLoopBodyStatements) {
+            addRange(statements, convertedLoopBodyStatements);
+        }
+        else {
+            const statement = visitNode(node.statement, visitor, isStatement);
+            if (isBlock(statement)) {
+                addRange(statements, statement.statements);
+                bodyLocation = statement;
+                statementsLocation = statement.statements;
+            }
+            else {
+                statements.push(statement);
+            }
+        }
+
+        // The old emitter does not emit source maps for the expression
+        setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression));
+
+        // The old emitter does not emit source maps for the block.
+        // We add the location to preserve comments.
+        const body = createBlock(
+            createNodeArray(statements, /*location*/ statementsLocation),
+            /*location*/ bodyLocation
+        );
+
+        setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
+
+        let forStatement: ForStatement | ForOfStatement;
+        if (convertObjectRest) {
+            forStatement = createForOf(
+                createVariableDeclarationList([
+                    createVariableDeclaration(rhsReference, /*type*/ undefined, /*initializer*/ undefined, /*location*/ node.expression)
+                ], /*location*/ node.expression),
+                node.expression,
+                body,
+                /*location*/ node
+            );
+        }
+        else {
+            forStatement = createFor(
+                setEmitFlags(
+                    createVariableDeclarationList([
+                        createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)),
+                        createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression)
+                    ], /*location*/ node.expression),
+                    EmitFlags.NoHoisting
+                ),
+                createLessThan(
+                    counter,
+                    createPropertyAccess(rhsReference, "length"),
+                    /*location*/ node.expression
+                ),
+                createPostfixIncrement(counter, /*location*/ node.expression),
+                body,
+                /*location*/ node
+            );
+        }
+
+        // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter.
+        setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps);
+        return forStatement;
+    }
 }

src/compiler/parser.ts

@@ -74,6 +74,8 @@ namespace ts {
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).questionToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).equalsToken) ||
                     visitNode(cbNode, (<ShorthandPropertyAssignment>node).objectAssignmentInitializer);
+            case SyntaxKind.SpreadAssignment:
+                return visitNode(cbNode, (<SpreadAssignment>node).expression);
             case SyntaxKind.Parameter:
             case SyntaxKind.PropertyDeclaration:
             case SyntaxKind.PropertySignature:
@@ -200,8 +202,8 @@ namespace ts {
                     visitNode(cbNode, (<ConditionalExpression>node).whenTrue) ||
                     visitNode(cbNode, (<ConditionalExpression>node).colonToken) ||
                     visitNode(cbNode, (<ConditionalExpression>node).whenFalse);
-            case SyntaxKind.SpreadElementExpression:
-                return visitNode(cbNode, (<SpreadElementExpression>node).expression);
+            case SyntaxKind.SpreadElement:
+                return visitNode(cbNode, (<SpreadElement>node).expression);
             case SyntaxKind.Block:
             case SyntaxKind.ModuleBlock:
                 return visitNodes(cbNodes, (<Block>node).statements);
@@ -441,6 +443,10 @@ namespace ts {
         return result;
     }
 
+    export function parseIsolatedEntityName(text: string, languageVersion: ScriptTarget): EntityName {
+        return Parser.parseIsolatedEntityName(text, languageVersion);
+    }
+
     export function isExternalModule(file: SourceFile): boolean {
         return file.externalModuleIndicator !== undefined;
     }
@@ -592,6 +598,16 @@ namespace ts {
             return result;
         }
 
+        export function parseIsolatedEntityName(content: string, languageVersion: ScriptTarget): EntityName {
+            initializeState(content, languageVersion, /*syntaxCursor*/ undefined, ScriptKind.JS);
+            // Prime the scanner.
+            nextToken();
+            const entityName = parseEntityName(/*allowReservedWords*/ true);
+            const isInvalid = token() === SyntaxKind.EndOfFileToken && !parseDiagnostics.length;
+            clearState();
+            return isInvalid ? entityName : undefined;
+        }
+
         function getLanguageVariant(scriptKind: ScriptKind) {
             // .tsx and .jsx files are treated as jsx language variant.
             return scriptKind === ScriptKind.TSX || scriptKind === ScriptKind.JSX || scriptKind === ScriptKind.JS ? LanguageVariant.JSX : LanguageVariant.Standard;
@@ -1272,9 +1288,11 @@ namespace ts {
                     // which would be a candidate for improved error reporting.
                     return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
                 case ParsingContext.ObjectLiteralMembers:
-                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.AsteriskToken || isLiteralPropertyName();
+                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.AsteriskToken || token() === SyntaxKind.DotDotDotToken || isLiteralPropertyName();
+                case ParsingContext.RestProperties:
+                    return isLiteralPropertyName();
                 case ParsingContext.ObjectBindingElements:
-                    return token() === SyntaxKind.OpenBracketToken || isLiteralPropertyName();
+                    return token() === SyntaxKind.OpenBracketToken || token() === SyntaxKind.DotDotDotToken || isLiteralPropertyName();
                 case ParsingContext.HeritageClauseElement:
                     // If we see { } then only consume it as an expression if it is followed by , or {
                     // That way we won't consume the body of a class in its heritage clause.
@@ -1401,6 +1419,7 @@ namespace ts {
                 case ParsingContext.ArrayBindingElements:
                     return token() === SyntaxKind.CloseBracketToken;
                 case ParsingContext.Parameters:
+                case ParsingContext.RestProperties:
                     // Tokens other than ')' and ']' (the latter for index signatures) are here for better error recovery
                     return token() === SyntaxKind.CloseParenToken || token() === SyntaxKind.CloseBracketToken /*|| token === SyntaxKind.OpenBraceToken*/;
                 case ParsingContext.TypeArguments:
@@ -1586,6 +1605,9 @@ namespace ts {
                 case ParsingContext.Parameters:
                     return isReusableParameter(node);
 
+                case ParsingContext.RestProperties:
+                    return false;
+
                 // Any other lists we do not care about reusing nodes in.  But feel free to add if
                 // you can do so safely.  Danger areas involve nodes that may involve speculative
                 // parsing.  If speculative parsing is involved with the node, then the range the
@@ -1783,6 +1805,7 @@ namespace ts {
                 case ParsingContext.BlockStatements: return Diagnostics.Declaration_or_statement_expected;
                 case ParsingContext.SwitchClauses: return Diagnostics.case_or_default_expected;
                 case ParsingContext.SwitchClauseStatements: return Diagnostics.Statement_expected;
+                case ParsingContext.RestProperties: // fallthrough
                 case ParsingContext.TypeMembers: return Diagnostics.Property_or_signature_expected;
                 case ParsingContext.ClassMembers: return Diagnostics.Unexpected_token_A_constructor_method_accessor_or_property_was_expected;
                 case ParsingContext.EnumMembers: return Diagnostics.Enum_member_expected;
@@ -4155,7 +4178,7 @@ namespace ts {
         }
 
         function parseSpreadElement(): Expression {
-            const node = <SpreadElementExpression>createNode(SyntaxKind.SpreadElementExpression);
+            const node = <SpreadElement>createNode(SyntaxKind.SpreadElement);
             parseExpected(SyntaxKind.DotDotDotToken);
             node.expression = parseAssignmentExpressionOrHigher();
             return finishNode(node);
@@ -4195,6 +4218,12 @@ namespace ts {
 
         function parseObjectLiteralElement(): ObjectLiteralElementLike {
             const fullStart = scanner.getStartPos();
+            const dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
+            if (dotDotDotToken) {
+                const spreadElement = <SpreadAssignment>createNode(SyntaxKind.SpreadAssignment, fullStart);
+                spreadElement.expression = parseAssignmentExpressionOrHigher();
+                return addJSDocComment(finishNode(spreadElement));
+            }
             const decorators = parseDecorators();
             const modifiers = parseModifiers();
 
@@ -4898,6 +4927,7 @@ namespace ts {
 
         function parseObjectBindingElement(): BindingElement {
             const node = <BindingElement>createNode(SyntaxKind.BindingElement);
+            node.dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
             const tokenIsIdentifier = isIdentifier();
             const propertyName = parsePropertyName();
             if (tokenIsIdentifier && token() !== SyntaxKind.ColonToken) {
@@ -5842,6 +5872,7 @@ namespace ts {
             JsxChildren,               // Things between opening and closing JSX tags
             ArrayLiteralMembers,       // Members in array literal
             Parameters,                // Parameters in parameter list
+            RestProperties,            // Property names in a rest type list
             TypeParameters,            // Type parameters in type parameter list
             TypeArguments,             // Type arguments in type argument list
             TupleElementTypes,         // Element types in tuple element type list

src/compiler/program.ts

@@ -908,48 +908,24 @@ namespace ts {
         function getJavaScriptSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
             return runWithCancellationToken(() => {
                 const diagnostics: Diagnostic[] = [];
+                let parent: Node = sourceFile;
                 walk(sourceFile);
 
                 return diagnostics;
 
-                function walk(node: Node): boolean {
-                    if (!node) {
-                        return false;
-                    }
+                function walk(node: Node) {
+                    // Return directly from the case if the given node doesnt want to visit each child
+                    // Otherwise break to visit each child
 
-                    switch (node.kind) {
-                        case SyntaxKind.ImportEqualsDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.import_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.ExportAssignment:
-                            if ((<ExportAssignment>node).isExportEquals) {
-                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.export_can_only_be_used_in_a_ts_file));
-                                return true;
+                    switch (parent.kind) {
+                        case SyntaxKind.Parameter:
+                        case SyntaxKind.PropertyDeclaration:
+                            if ((<ParameterDeclaration | PropertyDeclaration>parent).questionToken === node) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics._0_can_only_be_used_in_a_ts_file, "?"));
+                                return;
                             }
-                            break;
-                        case SyntaxKind.ClassDeclaration:
-                            let classDeclaration = <ClassDeclaration>node;
-                            if (checkModifiers(classDeclaration.modifiers) ||
-                                checkTypeParameters(classDeclaration.typeParameters)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.HeritageClause:
-                            let heritageClause = <HeritageClause>node;
-                            if (heritageClause.token === SyntaxKind.ImplementsKeyword) {
-                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.implements_clauses_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.InterfaceDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.interface_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.ModuleDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.module_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.TypeAliasDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.type_aliases_can_only_be_used_in_a_ts_file));
-                            return true;
+
+                        // Pass through
                         case SyntaxKind.MethodDeclaration:
                         case SyntaxKind.MethodSignature:
                         case SyntaxKind.Constructor:
@@ -959,124 +935,151 @@ namespace ts {
                         case SyntaxKind.FunctionDeclaration:
                         case SyntaxKind.ArrowFunction:
                         case SyntaxKind.FunctionDeclaration:
-                            const functionDeclaration = <FunctionLikeDeclaration>node;
-                            if (checkModifiers(functionDeclaration.modifiers) ||
-                                checkTypeParameters(functionDeclaration.typeParameters) ||
-                                checkTypeAnnotation(functionDeclaration.type)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.VariableStatement:
-                            const variableStatement = <VariableStatement>node;
-                            if (checkModifiers(variableStatement.modifiers)) {
-                                return true;
-                            }
-                            break;
                         case SyntaxKind.VariableDeclaration:
-                            const variableDeclaration = <VariableDeclaration>node;
-                            if (checkTypeAnnotation(variableDeclaration.type)) {
-                                return true;
+                            // type annotation
+                            if ((<FunctionLikeDeclaration | VariableDeclaration | ParameterDeclaration | PropertyDeclaration>parent).type === node) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.types_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                    }
+
+                    switch (node.kind) {
+                        case SyntaxKind.ImportEqualsDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.import_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.ExportAssignment:
+                            if ((<ExportAssignment>node).isExportEquals) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.export_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                            break;
+                        case SyntaxKind.HeritageClause:
+                            let heritageClause = <HeritageClause>node;
+                            if (heritageClause.token === SyntaxKind.ImplementsKeyword) {
+                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.implements_clauses_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                            break;
+                        case SyntaxKind.InterfaceDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.interface_declarations_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.ModuleDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.module_declarations_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.TypeAliasDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.type_aliases_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.EnumDeclaration:
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.enum_declarations_can_only_be_used_in_a_ts_file));
+                            return;
+                        case SyntaxKind.TypeAssertionExpression:
+                            let typeAssertionExpression = <TypeAssertion>node;
+                            diagnostics.push(createDiagnosticForNode(typeAssertionExpression.type, Diagnostics.type_assertion_expressions_can_only_be_used_in_a_ts_file));
+                            return;
+                    }
+
+                    const prevParent = parent;
+                    parent = node;
+                    forEachChild(node, walk, walkArray);
+                    parent = prevParent;
+                }
+
+                function walkArray(nodes: NodeArray<Node>) {
+                    if (parent.decorators === nodes && !options.experimentalDecorators) {
+                        diagnostics.push(createDiagnosticForNode(parent, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning));
+                    }
+
+                    switch (parent.kind) {
+                        case SyntaxKind.ClassDeclaration:
+                        case SyntaxKind.MethodDeclaration:
+                        case SyntaxKind.MethodSignature:
+                        case SyntaxKind.Constructor:
+                        case SyntaxKind.GetAccessor:
+                        case SyntaxKind.SetAccessor:
+                        case SyntaxKind.FunctionExpression:
+                        case SyntaxKind.FunctionDeclaration:
+                        case SyntaxKind.ArrowFunction:
+                        case SyntaxKind.FunctionDeclaration:
+                            // Check type parameters
+                            if (nodes === (<ClassDeclaration | FunctionLikeDeclaration>parent).typeParameters) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
+                                return;
+                            }
+                            // pass through
+                        case SyntaxKind.VariableStatement:
+                            // Check modifiers
+                            if (nodes === (<ClassDeclaration | FunctionLikeDeclaration | VariableStatement>parent).modifiers) {
+                                return checkModifiers(<NodeArray<Modifier>>nodes, parent.kind === SyntaxKind.VariableStatement);
+                            }
+                            break;
+                        case SyntaxKind.PropertyDeclaration:
+                            // Check modifiers of property declaration
+                            if (nodes === (<PropertyDeclaration>parent).modifiers) {
+                                for (const modifier of <NodeArray<Modifier>>nodes) {
+                                    if (modifier.kind !== SyntaxKind.StaticKeyword) {
+                                        diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
+                                    }
+                                }
+                                return;
+                            }
+                            break;
+                        case SyntaxKind.Parameter:
+                            // Check modifiers of parameter declaration
+                            if (nodes === (<ParameterDeclaration>parent).modifiers) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.parameter_modifiers_can_only_be_used_in_a_ts_file));
+                                return;
                             }
                             break;
                         case SyntaxKind.CallExpression:
                         case SyntaxKind.NewExpression:
-                            const expression = <CallExpression>node;
-                            if (expression.typeArguments && expression.typeArguments.length > 0) {
-                                const start = expression.typeArguments.pos;
-                                diagnostics.push(createFileDiagnostic(sourceFile, start, expression.typeArguments.end - start,
-                                    Diagnostics.type_arguments_can_only_be_used_in_a_ts_file));
-                                return true;
+                        case SyntaxKind.ExpressionWithTypeArguments:
+                            // Check type arguments
+                            if (nodes === (<CallExpression | NewExpression | ExpressionWithTypeArguments>parent).typeArguments) {
+                                diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_arguments_can_only_be_used_in_a_ts_file));
+                                return;
                             }
                             break;
-                        case SyntaxKind.Parameter:
-                            const parameter = <ParameterDeclaration>node;
-                            if (parameter.modifiers) {
-                                const start = parameter.modifiers.pos;
-                                diagnostics.push(createFileDiagnostic(sourceFile, start, parameter.modifiers.end - start,
-                                    Diagnostics.parameter_modifiers_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            if (parameter.questionToken) {
-                                diagnostics.push(createDiagnosticForNode(parameter.questionToken, Diagnostics._0_can_only_be_used_in_a_ts_file, "?"));
-                                return true;
-                            }
-                            if (parameter.type) {
-                                diagnostics.push(createDiagnosticForNode(parameter.type, Diagnostics.types_can_only_be_used_in_a_ts_file));
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.PropertyDeclaration:
-                            const propertyDeclaration = <PropertyDeclaration>node;
-                            if (propertyDeclaration.modifiers) {
-                                for (const modifier of propertyDeclaration.modifiers) {
-                                    if (modifier.kind !== SyntaxKind.StaticKeyword) {
-                                        diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
-                                        return true;
-                                    }
+                    }
+
+                    for (const node of nodes) {
+                        walk(node);
+                    }
+                }
+
+                function checkModifiers(modifiers: NodeArray<Modifier>, isConstValid: boolean) {
+                    for (const modifier of modifiers) {
+                        switch (modifier.kind) {
+                            case SyntaxKind.ConstKeyword:
+                                if (isConstValid) {
+                                    continue;
                                 }
-                            }
-                            if (checkTypeAnnotation((<PropertyDeclaration>node).type)) {
-                                return true;
-                            }
-                            break;
-                        case SyntaxKind.EnumDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.enum_declarations_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.TypeAssertionExpression:
-                            let typeAssertionExpression = <TypeAssertion>node;
-                            diagnostics.push(createDiagnosticForNode(typeAssertionExpression.type, Diagnostics.type_assertion_expressions_can_only_be_used_in_a_ts_file));
-                            return true;
-                        case SyntaxKind.Decorator:
-                            if (!options.experimentalDecorators) {
-                                diagnostics.push(createDiagnosticForNode(node, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning));
-                            }
-                            return true;
-                    }
+                                // Fallthrough to report error
+                            case SyntaxKind.PublicKeyword:
+                            case SyntaxKind.PrivateKeyword:
+                            case SyntaxKind.ProtectedKeyword:
+                            case SyntaxKind.ReadonlyKeyword:
+                            case SyntaxKind.DeclareKeyword:
+                            case SyntaxKind.AbstractKeyword:
+                                diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
+                                break;
 
-                    return forEachChild(node, walk);
-                }
-
-                function checkTypeParameters(typeParameters: NodeArray<TypeParameterDeclaration>): boolean {
-                    if (typeParameters) {
-                        const start = typeParameters.pos;
-                        diagnostics.push(createFileDiagnostic(sourceFile, start, typeParameters.end - start, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
-                        return true;
-                    }
-                    return false;
-                }
-
-                function checkTypeAnnotation(type: TypeNode): boolean {
-                    if (type) {
-                        diagnostics.push(createDiagnosticForNode(type, Diagnostics.types_can_only_be_used_in_a_ts_file));
-                        return true;
-                    }
-
-                    return false;
-                }
-
-                function checkModifiers(modifiers: NodeArray<Modifier>): boolean {
-                    if (modifiers) {
-                        for (const modifier of modifiers) {
-                            switch (modifier.kind) {
-                                case SyntaxKind.PublicKeyword:
-                                case SyntaxKind.PrivateKeyword:
-                                case SyntaxKind.ProtectedKeyword:
-                                case SyntaxKind.ReadonlyKeyword:
-                                case SyntaxKind.DeclareKeyword:
-                                    diagnostics.push(createDiagnosticForNode(modifier, Diagnostics._0_can_only_be_used_in_a_ts_file, tokenToString(modifier.kind)));
-                                    return true;
-
-                                // These are all legal modifiers.
-                                case SyntaxKind.StaticKeyword:
-                                case SyntaxKind.ExportKeyword:
-                                case SyntaxKind.ConstKeyword:
-                                case SyntaxKind.DefaultKeyword:
-                                case SyntaxKind.AbstractKeyword:
-                            }
+                            // These are all legal modifiers.
+                            case SyntaxKind.StaticKeyword:
+                            case SyntaxKind.ExportKeyword:
+                            case SyntaxKind.DefaultKeyword:
                         }
                     }
+                }
 
-                    return false;
+                function createDiagnosticForNodeArray(nodes: NodeArray<Node>, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
+                    const start = nodes.pos;
+                    return createFileDiagnostic(sourceFile, start, nodes.end - start, message, arg0, arg1, arg2);
+                }
+
+                // Since these are syntactic diagnostics, parent might not have been set
+                // this means the sourceFile cannot be infered from the node
+                function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
+                    return createDiagnosticForNodeInSourceFile(sourceFile, node, message, arg0, arg1, arg2);
                 }
             });
         }
@@ -1670,7 +1673,15 @@ namespace ts {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_without_specifying_option_1, "emitDecoratorMetadata", "experimentalDecorators"));
             }
 
-            if (options.reactNamespace && !isIdentifierText(options.reactNamespace, languageVersion)) {
+            if (options.jsxFactory) {
+                if (options.reactNamespace) {
+                    programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_0_cannot_be_specified_with_option_1, "reactNamespace", "jsxFactory"));
+                }
+                if (!parseIsolatedEntityName(options.jsxFactory, languageVersion)) {
+                    programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_jsxFactory_0_is_not_a_valid_identifier_or_qualified_name, options.jsxFactory));
+                }
+            }
+            else if (options.reactNamespace && !isIdentifierText(options.reactNamespace, languageVersion)) {
                 programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Invalid_value_for_reactNamespace_0_is_not_a_valid_identifier, options.reactNamespace));
             }
 

src/compiler/transformer.ts

@@ -1,6 +1,7 @@
 /// <reference path="visitor.ts" />
 /// <reference path="transformers/ts.ts" />
 /// <reference path="transformers/jsx.ts" />
+/// <reference path="transformers/esnext.ts" />
 /// <reference path="transformers/es2017.ts" />
 /// <reference path="transformers/es2016.ts" />
 /// <reference path="transformers/es2015.ts" />
@@ -116,6 +117,10 @@ namespace ts {
             transformers.push(transformJsx);
         }
 
+        if (languageVersion < ScriptTarget.ESNext) {
+            transformers.push(transformESNext);
+        }
+
         if (languageVersion < ScriptTarget.ES2017) {
             transformers.push(transformES2017);
         }

src/compiler/transformers/destructuring.ts

@@ -17,7 +17,8 @@ namespace ts {
         node: BinaryExpression,
         needsValue: boolean,
         recordTempVariable: (node: Identifier) => void,
-        visitor?: (node: Node) => VisitResult<Node>): Expression {
+        visitor?: (node: Node) => VisitResult<Node>,
+        transformRest?: boolean): Expression {
 
         if (isEmptyObjectLiteralOrArrayLiteral(node.left)) {
             const right = node.right;
@@ -51,7 +52,7 @@ namespace ts {
             location = value;
         }
 
-        flattenDestructuring(node, value, location, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, value, location, emitAssignment, emitTempVariableAssignment, recordTempVariable, emitRestAssignment, transformRest, visitor);
 
         if (needsValue) {
             expressions.push(value);
@@ -61,7 +62,7 @@ namespace ts {
         aggregateTransformFlags(expression);
         return expression;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange) {
+        function emitAssignment(name: Identifier | ObjectLiteralExpression, value: Expression, location: TextRange) {
             const expression = createAssignment(name, value, location);
 
             // NOTE: this completely disables source maps, but aligns with the behavior of
@@ -77,6 +78,10 @@ namespace ts {
             emitAssignment(name, value, location);
             return name;
         }
+
+        function emitRestAssignment(elements: ObjectLiteralElementLike[], value: Expression, location: TextRange) {
+            emitAssignment(createObjectLiteral(elements), value, location);
+        }
     }
 
     /**
@@ -89,14 +94,15 @@ namespace ts {
     export function flattenParameterDestructuring(
         node: ParameterDeclaration,
         value: Expression,
-        visitor?: (node: Node) => VisitResult<Node>) {
+        visitor?: (node: Node) => VisitResult<Node>,
+        transformRest?: boolean) {
         const declarations: VariableDeclaration[] = [];
 
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, noop, emitRestAssignment, transformRest, visitor);
 
         return declarations;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange) {
+        function emitAssignment(name: Identifier | BindingPattern, value: Expression, location: TextRange) {
             const declaration = createVariableDeclaration(name, /*type*/ undefined, value, location);
 
             // NOTE: this completely disables source maps, but aligns with the behavior of
@@ -112,6 +118,10 @@ namespace ts {
             emitAssignment(name, value, location);
             return name;
         }
+
+        function emitRestAssignment(elements: BindingElement[], value: Expression, location: TextRange) {
+            emitAssignment(createObjectBindingPattern(elements), value, location);
+        }
     }
 
     /**
@@ -125,15 +135,16 @@ namespace ts {
         node: VariableDeclaration,
         value?: Expression,
         visitor?: (node: Node) => VisitResult<Node>,
-        recordTempVariable?: (node: Identifier) => void) {
+        recordTempVariable?: (node: Identifier) => void,
+        transformRest?: boolean) {
         const declarations: VariableDeclaration[] = [];
 
         let pendingAssignments: Expression[];
-        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, value, node, emitAssignment, emitTempVariableAssignment, recordTempVariable, emitRestAssignment, transformRest, visitor);
 
         return declarations;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange, original: Node) {
+        function emitAssignment(name: Identifier | BindingPattern, value: Expression, location: TextRange, original: Node) {
             if (pendingAssignments) {
                 pendingAssignments.push(value);
                 value = inlineExpressions(pendingAssignments);
@@ -167,6 +178,10 @@ namespace ts {
             }
             return name;
         }
+
+        function emitRestAssignment(elements: BindingElement[], value: Expression, location: TextRange, original: Node) {
+            emitAssignment(createObjectBindingPattern(elements), value, location, original);
+        }
     }
 
     /**
@@ -186,15 +201,17 @@ namespace ts {
 
         const pendingAssignments: Expression[] = [];
 
-        flattenDestructuring(node, /*value*/ undefined, node, emitAssignment, emitTempVariableAssignment, visitor);
+        flattenDestructuring(node, /*value*/ undefined, node, emitAssignment, emitTempVariableAssignment, noop, emitRestAssignment, /*transformRest*/ false, visitor);
 
         const expression = inlineExpressions(pendingAssignments);
         aggregateTransformFlags(expression);
         return expression;
 
-        function emitAssignment(name: Identifier, value: Expression, location: TextRange, original: Node) {
+        function emitAssignment(name: Identifier | ObjectLiteralExpression, value: Expression, location: TextRange, original: Node) {
             const expression = createAssignmentCallback
-                ? createAssignmentCallback(name, value, location)
+                ? createAssignmentCallback(name.kind === SyntaxKind.Identifier ? name : emitTempVariableAssignment(name, location),
+                                           value,
+                                           location)
                 : createAssignment(name, value, location);
 
             emitPendingAssignment(expression, original);
@@ -206,6 +223,10 @@ namespace ts {
             return name;
         }
 
+        function emitRestAssignment(elements: ObjectLiteralElementLike[], value: Expression, location: TextRange, original: Node) {
+            emitAssignment(createObjectLiteral(elements), value, location, original);
+        }
+
         function emitPendingAssignment(expression: Expression, original: Node) {
             expression.original = original;
 
@@ -223,6 +244,9 @@ namespace ts {
         location: TextRange,
         emitAssignment: (name: Identifier, value: Expression, location: TextRange, original: Node) => void,
         emitTempVariableAssignment: (value: Expression, location: TextRange) => Identifier,
+        recordTempVariable: (node: Identifier) => void,
+        emitRestAssignment: (elements: (ObjectLiteralElementLike[] | BindingElement[]), value: Expression, location: TextRange, original: Node) => void,
+        transformRest: boolean,
         visitor?: (node: Node) => VisitResult<Node>) {
         if (value && visitor) {
             value = visitNode(value, visitor, isExpression);
@@ -284,23 +308,91 @@ namespace ts {
                 value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
             }
 
-            for (const p of properties) {
+            let bindingElements: ObjectLiteralElementLike[] = [];
+            for (let i = 0; i < properties.length; i++) {
+                const p = properties[i];
                 if (p.kind === SyntaxKind.PropertyAssignment || p.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                    const propName = <Identifier | LiteralExpression>(<PropertyAssignment>p).name;
-                    const target = p.kind === SyntaxKind.ShorthandPropertyAssignment ? <ShorthandPropertyAssignment>p : (<PropertyAssignment>p).initializer || propName;
-                    // Assignment for target = value.propName should highligh whole property, hence use p as source map node
-                    emitDestructuringAssignment(target, createDestructuringPropertyAccess(value, propName), p);
+                    if (!transformRest ||
+                        p.transformFlags & TransformFlags.ContainsSpreadExpression ||
+                        (p.kind === SyntaxKind.PropertyAssignment && p.initializer.transformFlags & TransformFlags.ContainsSpreadExpression)) {
+                        if (bindingElements.length) {
+                            emitRestAssignment(bindingElements, value, location, target);
+                            bindingElements = [];
+                        }
+                        const propName = <Identifier | LiteralExpression>(<PropertyAssignment>p).name;
+                        const bindingTarget = p.kind === SyntaxKind.ShorthandPropertyAssignment ? <ShorthandPropertyAssignment>p : (<PropertyAssignment>p).initializer || propName;
+                        // Assignment for bindingTarget = value.propName should highlight whole property, hence use p as source map node
+                        emitDestructuringAssignment(bindingTarget, createDestructuringPropertyAccess(value, propName), p);
+                    }
+                    else {
+                        bindingElements.push(p);
+                    }
                 }
+                else if (i === properties.length - 1 && p.kind === SyntaxKind.SpreadAssignment) {
+                    Debug.assert((p as SpreadAssignment).expression.kind === SyntaxKind.Identifier);
+                    if (bindingElements.length) {
+                        emitRestAssignment(bindingElements, value, location, target);
+                        bindingElements = [];
+                    }
+                    const propName = (p as SpreadAssignment).expression as Identifier;
+                    const restCall = createRestCall(value, target.properties, p => p.name, target);
+                    emitDestructuringAssignment(propName, restCall, p);
+                }
+            }
+            if (bindingElements.length) {
+                emitRestAssignment(bindingElements, value, location, target);
+                bindingElements = [];
             }
         }
 
         function emitArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
+            if (transformRest) {
+                emitESNextArrayLiteralAssignment(target, value, location);
+            }
+            else {
+                emitES2015ArrayLiteralAssignment(target, value, location);
+            }
+        }
+
+        function emitESNextArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
             const elements = target.elements;
             const numElements = elements.length;
             if (numElements !== 1) {
                 // For anything but a single element destructuring we need to generate a temporary
                 // to ensure value is evaluated exactly once.
-                // When doing so we want to hightlight the passed in source map node since thats the one needing this temp assignment
+                // When doing so we want to highlight the passed-in source map node since thats the one needing this temp assignment
+                value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
+            }
+
+            const expressions: Expression[] = [];
+            const spreadContainingExpressions: [Expression, Identifier][] = [];
+            for (let i = 0; i < numElements; i++) {
+                const e = elements[i];
+                if (e.kind === SyntaxKind.OmittedExpression) {
+                    continue;
+                }
+                if (e.transformFlags & TransformFlags.ContainsSpreadExpression && i < numElements - 1) {
+                    const tmp = createTempVariable(recordTempVariable);
+                    spreadContainingExpressions.push([e, tmp]);
+                    expressions.push(tmp);
+                }
+                else {
+                    expressions.push(e);
+                }
+            }
+            emitAssignment(updateArrayLiteral(target, expressions) as any as Identifier, value, undefined, undefined);
+            for (const [e, tmp] of spreadContainingExpressions) {
+                emitDestructuringAssignment(e, tmp, e);
+            }
+        }
+
+        function emitES2015ArrayLiteralAssignment(target: ArrayLiteralExpression, value: Expression, location: TextRange) {
+            const elements = target.elements;
+            const numElements = elements.length;
+            if (numElements !== 1) {
+                // For anything but a single element destructuring we need to generate a temporary
+                // to ensure value is evaluated exactly once.
+                // When doing so we want to highlight the passed-in source map node since thats the one needing this temp assignment
                 value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ true, location, emitTempVariableAssignment);
             }
 
@@ -308,20 +400,41 @@ namespace ts {
                 const e = elements[i];
                 if (e.kind !== SyntaxKind.OmittedExpression) {
                     // Assignment for target = value.propName should highligh whole property, hence use e as source map node
-                    if (e.kind !== SyntaxKind.SpreadElementExpression) {
+                    if (e.kind !== SyntaxKind.SpreadElement) {
                         emitDestructuringAssignment(e, createElementAccess(value, createLiteral(i)), e);
                     }
                     else if (i === numElements - 1) {
-                        emitDestructuringAssignment((<SpreadElementExpression>e).expression, createArraySlice(value, i), e);
+                        emitDestructuringAssignment((<SpreadElement>e).expression, createArraySlice(value, i), e);
                     }
                 }
             }
         }
 
+        /** Given value: o, propName: p, pattern: { a, b, ...p } from the original statement
+         * `{ a, b, ...p } = o`, create `p = __rest(o, ["a", "b"]);`*/
+        function createRestCall<T extends Node>(value: Expression, elements: T[], getPropertyName: (element: T) => PropertyName, location: TextRange): Expression {
+            const propertyNames: LiteralExpression[] = [];
+            for (let i = 0; i < elements.length - 1; i++) {
+                if (isOmittedExpression(elements[i])) {
+                    continue;
+                }
+                const str = <StringLiteral>createSynthesizedNode(SyntaxKind.StringLiteral);
+                str.pos = location.pos;
+                str.end = location.end;
+                str.text = getTextOfPropertyName(getPropertyName(elements[i]));
+                propertyNames.push(str);
+            }
+            const args = createSynthesizedNodeArray([value, createArrayLiteral(propertyNames, location)]);
+            return createCall(createIdentifier("__rest"), undefined, args);
+        }
+
         function emitBindingElement(target: VariableDeclaration | ParameterDeclaration | BindingElement, value: Expression) {
             // Any temporary assignments needed to emit target = value should point to target
             const initializer = visitor ? visitNode(target.initializer, visitor, isExpression) : target.initializer;
-            if (initializer) {
+            if (transformRest) {
+                value = value || initializer;
+            }
+            else if (initializer) {
                 // Combine value and initializer
                 value = value ? createDefaultValueCheck(value, initializer, target) : initializer;
             }
@@ -331,9 +444,11 @@ namespace ts {
             }
 
             const name = target.name;
-            if (isBindingPattern(name)) {
-                const elements = name.elements;
-                const numElements = elements.length;
+            if (!isBindingPattern(name)) {
+                emitAssignment(name, value, target, target);
+            }
+            else {
+                const numElements = name.elements.length;
                 if (numElements !== 1) {
                     // For anything other than a single-element destructuring we need to generate a temporary
                     // to ensure value is evaluated exactly once. Additionally, if we have zero elements
@@ -341,29 +456,104 @@ namespace ts {
                     // so in that case, we'll intentionally create that temporary.
                     value = ensureIdentifier(value, /*reuseIdentifierExpressions*/ numElements !== 0, target, emitTempVariableAssignment);
                 }
-                for (let i = 0; i < numElements; i++) {
-                    const element = elements[i];
-                    if (isOmittedExpression(element)) {
-                        continue;
-                    }
-                    else if (name.kind === SyntaxKind.ObjectBindingPattern) {
-                        // Rewrite element to a declaration with an initializer that fetches property
-                        const propName = element.propertyName || <Identifier>element.name;
-                        emitBindingElement(element, createDestructuringPropertyAccess(value, propName));
-                    }
-                    else {
-                        if (!element.dotDotDotToken) {
-                            // Rewrite element to a declaration that accesses array element at index i
-                            emitBindingElement(element, createElementAccess(value, i));
-                        }
-                        else if (i === numElements - 1) {
-                            emitBindingElement(element, createArraySlice(value, i));
-                        }
-                    }
+                if (name.kind === SyntaxKind.ArrayBindingPattern) {
+                    emitArrayBindingElement(name as ArrayBindingPattern, value);
+                }
+                else {
+                    emitObjectBindingElement(target, value);
                 }
             }
+        }
+
+        function emitArrayBindingElement(name: ArrayBindingPattern, value: Expression) {
+            if (transformRest) {
+                emitESNextArrayBindingElement(name, value);
+            }
             else {
-                emitAssignment(name, value, target, target);
+                emitES2015ArrayBindingElement(name, value);
+            }
+        }
+
+        function emitES2015ArrayBindingElement(name: ArrayBindingPattern, value: Expression) {
+            const elements = name.elements;
+            const numElements = elements.length;
+            for (let i = 0; i < numElements; i++) {
+                const element = elements[i];
+                if (isOmittedExpression(element)) {
+                    continue;
+                }
+                if (!element.dotDotDotToken) {
+                    // Rewrite element to a declaration that accesses array element at index i
+                    emitBindingElement(element, createElementAccess(value, i));
+                }
+                else if (i === numElements - 1) {
+                    emitBindingElement(element, createArraySlice(value, i));
+                }
+            }
+        }
+
+        function emitESNextArrayBindingElement(name: ArrayBindingPattern, value: Expression) {
+            const elements = name.elements;
+            const numElements = elements.length;
+            const bindingElements: BindingElement[] = [];
+            const spreadContainingElements: BindingElement[] = [];
+            for (let i = 0; i < numElements; i++) {
+                const element = elements[i];
+                if (isOmittedExpression(element)) {
+                    continue;
+                }
+                if (element.transformFlags & TransformFlags.ContainsSpreadExpression && i < numElements - 1) {
+                    spreadContainingElements.push(element);
+                    bindingElements.push(createBindingElement(undefined, undefined, getGeneratedNameForNode(element), undefined, value));
+                }
+                else {
+                    bindingElements.push(element);
+                }
+            }
+            emitAssignment(updateArrayBindingPattern(name, bindingElements) as any as Identifier, value, undefined, undefined);
+            for (const element of spreadContainingElements) {
+                emitBindingElement(element, getGeneratedNameForNode(element));
+            }
+        }
+
+        function emitObjectBindingElement(target: VariableDeclaration | ParameterDeclaration | BindingElement, value: Expression) {
+            const name = target.name as BindingPattern;
+            const elements = name.elements;
+            const numElements = elements.length;
+            let bindingElements: BindingElement[] = [];
+            for (let i = 0; i < numElements; i++) {
+                const element = elements[i];
+                if (isOmittedExpression(element)) {
+                    continue;
+                }
+                if (i === numElements - 1 && element.dotDotDotToken) {
+                    if (bindingElements.length) {
+                        emitRestAssignment(bindingElements, value, target, target);
+                        bindingElements = [];
+                    }
+                    const restCall = createRestCall(value,
+                                                    name.elements,
+                                                    element => (element as BindingElement).propertyName || <Identifier>(element as BindingElement).name,
+                                                    name);
+                    emitBindingElement(element, restCall);
+                }
+                else if (transformRest && !(element.transformFlags & TransformFlags.ContainsSpreadExpression)) {
+                    // do not emit until we have a complete bundle of ES2015 syntax
+                    bindingElements.push(element);
+                }
+                else {
+                    if (bindingElements.length) {
+                        emitRestAssignment(bindingElements, value, target, target);
+                        bindingElements = [];
+                    }
+                    // Rewrite element to a declaration with an initializer that fetches property
+                    const propName = element.propertyName || <Identifier>element.name;
+                    emitBindingElement(element, createDestructuringPropertyAccess(value, propName));
+                }
+            }
+            if (bindingElements.length) {
+                emitRestAssignment(bindingElements, value, target, target);
+                bindingElements = [];
             }
         }
 

src/compiler/transformers/es2015.ts

@@ -861,7 +861,7 @@ namespace ts {
             }
 
             if (constructor) {
-                addDefaultValueAssignmentsIfNeeded(statements, constructor);
+                addDefaultValueAssignmentsIfNeeded(statements, constructor, visitor, /*convertObjectRest*/ false);
                 addRestParameterIfNeeded(statements, constructor, hasSynthesizedSuper);
                 Debug.assert(statementOffset >= 0, "statementOffset not initialized correctly!");
 
@@ -954,7 +954,7 @@ namespace ts {
             // If this isn't a derived class, just capture 'this' for arrow functions if necessary.
             if (!hasExtendsClause) {
                 if (ctor) {
-                    addCaptureThisForNodeIfNeeded(statements, ctor);
+                    addCaptureThisForNodeIfNeeded(statements, ctor, enableSubstitutionsForCapturedThis);
                 }
                 return SuperCaptureResult.NoReplacement;
             }
@@ -1016,7 +1016,7 @@ namespace ts {
             }
 
             // Perform the capture.
-            captureThisForNode(statements, ctor, superCallExpression, firstStatement);
+            captureThisForNode(statements, ctor, superCallExpression, enableSubstitutionsForCapturedThis, firstStatement);
 
             // If we're actually replacing the original statement, we need to signal this to the caller.
             if (superCallExpression) {
@@ -1085,242 +1085,6 @@ namespace ts {
             }
         }
 
-        /**
-         * Gets a value indicating whether we need to add default value assignments for a
-         * function-like node.
-         *
-         * @param node A function-like node.
-         */
-        function shouldAddDefaultValueAssignments(node: FunctionLikeDeclaration): boolean {
-            return (node.transformFlags & TransformFlags.ContainsDefaultValueAssignments) !== 0;
-        }
-
-        /**
-         * Adds statements to the body of a function-like node if it contains parameters with
-         * binding patterns or initializers.
-         *
-         * @param statements The statements for the new function body.
-         * @param node A function-like node.
-         */
-        function addDefaultValueAssignmentsIfNeeded(statements: Statement[], node: FunctionLikeDeclaration): void {
-            if (!shouldAddDefaultValueAssignments(node)) {
-                return;
-            }
-
-            for (const parameter of node.parameters) {
-                const { name, initializer, dotDotDotToken } = parameter;
-
-                // A rest parameter cannot have a binding pattern or an initializer,
-                // so let's just ignore it.
-                if (dotDotDotToken) {
-                    continue;
-                }
-
-                if (isBindingPattern(name)) {
-                    addDefaultValueAssignmentForBindingPattern(statements, parameter, name, initializer);
-                }
-                else if (initializer) {
-                    addDefaultValueAssignmentForInitializer(statements, parameter, name, initializer);
-                }
-            }
-        }
-
-        /**
-         * Adds statements to the body of a function-like node for parameters with binding patterns
-         *
-         * @param statements The statements for the new function body.
-         * @param parameter The parameter for the function.
-         * @param name The name of the parameter.
-         * @param initializer The initializer for the parameter.
-         */
-        function addDefaultValueAssignmentForBindingPattern(statements: Statement[], parameter: ParameterDeclaration, name: BindingPattern, initializer: Expression): void {
-            const temp = getGeneratedNameForNode(parameter);
-
-            // In cases where a binding pattern is simply '[]' or '{}',
-            // we usually don't want to emit a var declaration; however, in the presence
-            // of an initializer, we must emit that expression to preserve side effects.
-            if (name.elements.length > 0) {
-                statements.push(
-                    setEmitFlags(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            createVariableDeclarationList(
-                                flattenParameterDestructuring(parameter, temp, visitor)
-                            )
-                        ),
-                        EmitFlags.CustomPrologue
-                    )
-                );
-            }
-            else if (initializer) {
-                statements.push(
-                    setEmitFlags(
-                        createStatement(
-                            createAssignment(
-                                temp,
-                                visitNode(initializer, visitor, isExpression)
-                            )
-                        ),
-                        EmitFlags.CustomPrologue
-                    )
-                );
-            }
-        }
-
-        /**
-         * Adds statements to the body of a function-like node for parameters with initializers.
-         *
-         * @param statements The statements for the new function body.
-         * @param parameter The parameter for the function.
-         * @param name The name of the parameter.
-         * @param initializer The initializer for the parameter.
-         */
-        function addDefaultValueAssignmentForInitializer(statements: Statement[], parameter: ParameterDeclaration, name: Identifier, initializer: Expression): void {
-            initializer = visitNode(initializer, visitor, isExpression);
-            const statement = createIf(
-                createStrictEquality(
-                    getSynthesizedClone(name),
-                    createVoidZero()
-                ),
-                setEmitFlags(
-                    createBlock([
-                        createStatement(
-                            createAssignment(
-                                setEmitFlags(getMutableClone(name), EmitFlags.NoSourceMap),
-                                setEmitFlags(initializer, EmitFlags.NoSourceMap | getEmitFlags(initializer)),
-                                /*location*/ parameter
-                            )
-                        )
-                    ], /*location*/ parameter),
-                    EmitFlags.SingleLine | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTokenSourceMaps
-                ),
-                /*elseStatement*/ undefined,
-                /*location*/ parameter
-            );
-            statement.startsOnNewLine = true;
-            setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.CustomPrologue);
-            statements.push(statement);
-        }
-
-        /**
-         * Gets a value indicating whether we need to add statements to handle a rest parameter.
-         *
-         * @param node A ParameterDeclaration node.
-         * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
-         *                                          part of a constructor declaration with a
-         *                                          synthesized call to `super`
-         */
-        function shouldAddRestParameter(node: ParameterDeclaration, inConstructorWithSynthesizedSuper: boolean) {
-            return node && node.dotDotDotToken && node.name.kind === SyntaxKind.Identifier && !inConstructorWithSynthesizedSuper;
-        }
-
-        /**
-         * Adds statements to the body of a function-like node if it contains a rest parameter.
-         *
-         * @param statements The statements for the new function body.
-         * @param node A function-like node.
-         * @param inConstructorWithSynthesizedSuper A value indicating whether the parameter is
-         *                                          part of a constructor declaration with a
-         *                                          synthesized call to `super`
-         */
-        function addRestParameterIfNeeded(statements: Statement[], node: FunctionLikeDeclaration, inConstructorWithSynthesizedSuper: boolean): void {
-            const parameter = lastOrUndefined(node.parameters);
-            if (!shouldAddRestParameter(parameter, inConstructorWithSynthesizedSuper)) {
-                return;
-            }
-
-            // `declarationName` is the name of the local declaration for the parameter.
-            const declarationName = getMutableClone(<Identifier>parameter.name);
-            setEmitFlags(declarationName, EmitFlags.NoSourceMap);
-
-            // `expressionName` is the name of the parameter used in expressions.
-            const expressionName = getSynthesizedClone(<Identifier>parameter.name);
-            const restIndex = node.parameters.length - 1;
-            const temp = createLoopVariable();
-
-            // var param = [];
-            statements.push(
-                setEmitFlags(
-                    createVariableStatement(
-                        /*modifiers*/ undefined,
-                        createVariableDeclarationList([
-                            createVariableDeclaration(
-                                declarationName,
-                                /*type*/ undefined,
-                                createArrayLiteral([])
-                            )
-                        ]),
-                        /*location*/ parameter
-                    ),
-                    EmitFlags.CustomPrologue
-                )
-            );
-
-            // for (var _i = restIndex; _i < arguments.length; _i++) {
-            //   param[_i - restIndex] = arguments[_i];
-            // }
-            const forStatement = createFor(
-                createVariableDeclarationList([
-                    createVariableDeclaration(temp, /*type*/ undefined, createLiteral(restIndex))
-                ], /*location*/ parameter),
-                createLessThan(
-                    temp,
-                    createPropertyAccess(createIdentifier("arguments"), "length"),
-                    /*location*/ parameter
-                ),
-                createPostfixIncrement(temp, /*location*/ parameter),
-                createBlock([
-                    startOnNewLine(
-                        createStatement(
-                            createAssignment(
-                                createElementAccess(
-                                    expressionName,
-                                    createSubtract(temp, createLiteral(restIndex))
-                                ),
-                                createElementAccess(createIdentifier("arguments"), temp)
-                            ),
-                            /*location*/ parameter
-                        )
-                    )
-                ])
-            );
-
-            setEmitFlags(forStatement, EmitFlags.CustomPrologue);
-            startOnNewLine(forStatement);
-            statements.push(forStatement);
-        }
-
-        /**
-         * Adds a statement to capture the `this` of a function declaration if it is needed.
-         *
-         * @param statements The statements for the new function body.
-         * @param node A node.
-         */
-        function addCaptureThisForNodeIfNeeded(statements: Statement[], node: Node): void {
-            if (node.transformFlags & TransformFlags.ContainsCapturedLexicalThis && node.kind !== SyntaxKind.ArrowFunction) {
-                captureThisForNode(statements, node, createThis());
-            }
-        }
-
-        function captureThisForNode(statements: Statement[], node: Node, initializer: Expression | undefined, originalStatement?: Statement): void {
-            enableSubstitutionsForCapturedThis();
-            const captureThisStatement = createVariableStatement(
-                /*modifiers*/ undefined,
-                createVariableDeclarationList([
-                    createVariableDeclaration(
-                        "_this",
-                        /*type*/ undefined,
-                        initializer
-                    )
-                ]),
-                originalStatement
-            );
-
-            setEmitFlags(captureThisStatement, EmitFlags.NoComments | EmitFlags.CustomPrologue);
-            setSourceMapRange(captureThisStatement, node);
-            statements.push(captureThisStatement);
-        }
-
         /**
          * Adds statements to the class body function for a class to define the members of the
          * class.
@@ -1518,7 +1282,7 @@ namespace ts {
                     /*typeParameters*/ undefined,
                     visitNodes(node.parameters, visitor, isParameter),
                     /*type*/ undefined,
-                    transformFunctionBody(node),
+                    transformFunctionBody(node, visitor, currentSourceFile, context, enableSubstitutionsForCapturedThis),
                     /*location*/ node
                 ),
                 /*original*/ node);
@@ -1545,7 +1309,7 @@ namespace ts {
                     /*typeParameters*/ undefined,
                     visitNodes(node.parameters, visitor, isParameter),
                     /*type*/ undefined,
-                    saveStateAndInvoke(node, transformFunctionBody),
+                    saveStateAndInvoke(node, node => transformFunctionBody(node, visitor, currentSourceFile, context, enableSubstitutionsForCapturedThis)),
                     location
                 ),
                 /*original*/ node
@@ -1555,96 +1319,6 @@ namespace ts {
             return expression;
         }
 
-        /**
-         * Transforms the body of a function-like node.
-         *
-         * @param node A function-like node.
-         */
-        function transformFunctionBody(node: FunctionLikeDeclaration) {
-            let multiLine = false; // indicates whether the block *must* be emitted as multiple lines
-            let singleLine = false; // indicates whether the block *may* be emitted as a single line
-            let statementsLocation: TextRange;
-            let closeBraceLocation: TextRange;
-
-            const statements: Statement[] = [];
-            const body = node.body;
-            let statementOffset: number;
-
-            startLexicalEnvironment();
-            if (isBlock(body)) {
-                // ensureUseStrict is false because no new prologue-directive should be added.
-                // addPrologueDirectives will simply put already-existing directives at the beginning of the target statement-array
-                statementOffset = addPrologueDirectives(statements, body.statements, /*ensureUseStrict*/ false, visitor);
-            }
-
-            addCaptureThisForNodeIfNeeded(statements, node);
-            addDefaultValueAssignmentsIfNeeded(statements, node);
-            addRestParameterIfNeeded(statements, node, /*inConstructorWithSynthesizedSuper*/ false);
-
-            // If we added any generated statements, this must be a multi-line block.
-            if (!multiLine && statements.length > 0) {
-                multiLine = true;
-            }
-
-            if (isBlock(body)) {
-                statementsLocation = body.statements;
-                addRange(statements, visitNodes(body.statements, visitor, isStatement, statementOffset));
-
-                // If the original body was a multi-line block, this must be a multi-line block.
-                if (!multiLine && body.multiLine) {
-                    multiLine = true;
-                }
-            }
-            else {
-                Debug.assert(node.kind === SyntaxKind.ArrowFunction);
-
-                // To align with the old emitter, we use a synthetic end position on the location
-                // for the statement list we synthesize when we down-level an arrow function with
-                // an expression function body. This prevents both comments and source maps from
-                // being emitted for the end position only.
-                statementsLocation = moveRangeEnd(body, -1);
-
-                const equalsGreaterThanToken = (<ArrowFunction>node).equalsGreaterThanToken;
-                if (!nodeIsSynthesized(equalsGreaterThanToken) && !nodeIsSynthesized(body)) {
-                    if (rangeEndIsOnSameLineAsRangeStart(equalsGreaterThanToken, body, currentSourceFile)) {
-                        singleLine = true;
-                    }
-                    else {
-                        multiLine = true;
-                    }
-                }
-
-                const expression = visitNode(body, visitor, isExpression);
-                const returnStatement = createReturn(expression, /*location*/ body);
-                setEmitFlags(returnStatement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTrailingComments);
-                statements.push(returnStatement);
-
-                // To align with the source map emit for the old emitter, we set a custom
-                // source map location for the close brace.
-                closeBraceLocation = body;
-            }
-
-            const lexicalEnvironment = endLexicalEnvironment();
-            addRange(statements, lexicalEnvironment);
-
-            // If we added any final generated statements, this must be a multi-line block
-            if (!multiLine && lexicalEnvironment && lexicalEnvironment.length) {
-                multiLine = true;
-            }
-
-            const block = createBlock(createNodeArray(statements, statementsLocation), node.body, multiLine);
-            if (!multiLine && singleLine) {
-                setEmitFlags(block, EmitFlags.SingleLine);
-            }
-
-            if (closeBraceLocation) {
-                setTokenSourceMapRange(block, SyntaxKind.CloseBraceToken, closeBraceLocation);
-            }
-
-            setOriginalNode(block, node.body);
-            return block;
-        }
-
         /**
          * Visits an ExpressionStatement that contains a destructuring assignment.
          *
@@ -1926,171 +1600,7 @@ namespace ts {
         }
 
         function convertForOfToFor(node: ForOfStatement, convertedLoopBodyStatements: Statement[]): ForStatement {
-            // The following ES6 code:
-            //
-            //    for (let v of expr) { }
-            //
-            // should be emitted as
-            //
-            //    for (var _i = 0, _a = expr; _i < _a.length; _i++) {
-            //        var v = _a[_i];
-            //    }
-            //
-            // where _a and _i are temps emitted to capture the RHS and the counter,
-            // respectively.
-            // When the left hand side is an expression instead of a let declaration,
-            // the "let v" is not emitted.
-            // When the left hand side is a let/const, the v is renamed if there is
-            // another v in scope.
-            // Note that all assignments to the LHS are emitted in the body, including
-            // all destructuring.
-            // Note also that because an extra statement is needed to assign to the LHS,
-            // for-of bodies are always emitted as blocks.
-
-            const expression = visitNode(node.expression, visitor, isExpression);
-            const initializer = node.initializer;
-            const statements: Statement[] = [];
-
-            // In the case where the user wrote an identifier as the RHS, like this:
-            //
-            //     for (let v of arr) { }
-            //
-            // we don't want to emit a temporary variable for the RHS, just use it directly.
-            const counter = createLoopVariable();
-            const rhsReference = expression.kind === SyntaxKind.Identifier
-                ? createUniqueName((<Identifier>expression).text)
-                : createTempVariable(/*recordTempVariable*/ undefined);
-
-            // Initialize LHS
-            // var v = _a[_i];
-            if (isVariableDeclarationList(initializer)) {
-                if (initializer.flags & NodeFlags.BlockScoped) {
-                    enableSubstitutionsForBlockScopedBindings();
-                }
-
-                const firstOriginalDeclaration = firstOrUndefined(initializer.declarations);
-                if (firstOriginalDeclaration && isBindingPattern(firstOriginalDeclaration.name)) {
-                    // This works whether the declaration is a var, let, or const.
-                    // It will use rhsIterationValue _a[_i] as the initializer.
-                    const declarations = flattenVariableDestructuring(
-                        firstOriginalDeclaration,
-                        createElementAccess(rhsReference, counter),
-                        visitor
-                    );
-
-                    const declarationList = createVariableDeclarationList(declarations, /*location*/ initializer);
-                    setOriginalNode(declarationList, initializer);
-
-                    // Adjust the source map range for the first declaration to align with the old
-                    // emitter.
-                    const firstDeclaration = declarations[0];
-                    const lastDeclaration = lastOrUndefined(declarations);
-                    setSourceMapRange(declarationList, createRange(firstDeclaration.pos, lastDeclaration.end));
-
-                    statements.push(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            declarationList
-                        )
-                    );
-                }
-                else {
-                    // The following call does not include the initializer, so we have
-                    // to emit it separately.
-                    statements.push(
-                        createVariableStatement(
-                            /*modifiers*/ undefined,
-                            setOriginalNode(
-                                createVariableDeclarationList([
-                                    createVariableDeclaration(
-                                        firstOriginalDeclaration ? firstOriginalDeclaration.name : createTempVariable(/*recordTempVariable*/ undefined),
-                                        /*type*/ undefined,
-                                        createElementAccess(rhsReference, counter)
-                                    )
-                                ], /*location*/ moveRangePos(initializer, -1)),
-                                initializer
-                            ),
-                            /*location*/ moveRangeEnd(initializer, -1)
-                        )
-                    );
-                }
-            }
-            else {
-                // Initializer is an expression. Emit the expression in the body, so that it's
-                // evaluated on every iteration.
-                const assignment = createAssignment(initializer, createElementAccess(rhsReference, counter));
-                if (isDestructuringAssignment(assignment)) {
-                    // This is a destructuring pattern, so we flatten the destructuring instead.
-                    statements.push(
-                        createStatement(
-                            flattenDestructuringAssignment(
-                                context,
-                                assignment,
-                                /*needsValue*/ false,
-                                hoistVariableDeclaration,
-                                visitor
-                            )
-                        )
-                    );
-                }
-                else {
-                    // Currently there is not way to check that assignment is binary expression of destructing assignment
-                    // so we have to cast never type to binaryExpression
-                    (<BinaryExpression>assignment).end = initializer.end;
-                    statements.push(createStatement(assignment, /*location*/ moveRangeEnd(initializer, -1)));
-                }
-            }
-
-            let bodyLocation: TextRange;
-            let statementsLocation: TextRange;
-            if (convertedLoopBodyStatements) {
-                addRange(statements, convertedLoopBodyStatements);
-            }
-            else {
-                const statement = visitNode(node.statement, visitor, isStatement);
-                if (isBlock(statement)) {
-                    addRange(statements, statement.statements);
-                    bodyLocation = statement;
-                    statementsLocation = statement.statements;
-                }
-                else {
-                    statements.push(statement);
-                }
-            }
-
-            // The old emitter does not emit source maps for the expression
-            setEmitFlags(expression, EmitFlags.NoSourceMap | getEmitFlags(expression));
-
-            // The old emitter does not emit source maps for the block.
-            // We add the location to preserve comments.
-            const body = createBlock(
-                createNodeArray(statements, /*location*/ statementsLocation),
-                /*location*/ bodyLocation
-            );
-
-            setEmitFlags(body, EmitFlags.NoSourceMap | EmitFlags.NoTokenSourceMaps);
-
-            const forStatement = createFor(
-                setEmitFlags(
-                    createVariableDeclarationList([
-                        createVariableDeclaration(counter, /*type*/ undefined, createLiteral(0), /*location*/ moveRangePos(node.expression, -1)),
-                        createVariableDeclaration(rhsReference, /*type*/ undefined, expression, /*location*/ node.expression)
-                    ], /*location*/ node.expression),
-                    EmitFlags.NoHoisting
-                ),
-                createLessThan(
-                    counter,
-                    createPropertyAccess(rhsReference, "length"),
-                    /*location*/ node.expression
-                ),
-                createPostfixIncrement(counter, /*location*/ node.expression),
-                body,
-                /*location*/ node
-            );
-
-            // Disable trailing source maps for the OpenParenToken to align source map emit with the old emitter.
-            setEmitFlags(forStatement, EmitFlags.NoTokenTrailingSourceMaps);
-            return forStatement;
+            return <ForStatement>convertForOf(node, convertedLoopBodyStatements, visitor, enableSubstitutionsForBlockScopedBindings, context, /*transformRest*/ false);
         }
 
         /**
@@ -2751,7 +2261,7 @@ namespace ts {
                 setEmitFlags(thisArg, EmitFlags.NoSubstitution);
             }
             let resultingCall: CallExpression | BinaryExpression;
-            if (node.transformFlags & TransformFlags.ContainsSpreadElementExpression) {
+            if (node.transformFlags & TransformFlags.ContainsSpreadExpression) {
                 // [source]
                 //      f(...a, b)
                 //      x.m(...a, b)
@@ -2813,7 +2323,7 @@ namespace ts {
          */
         function visitNewExpression(node: NewExpression): LeftHandSideExpression {
             // We are here because we contain a SpreadElementExpression.
-            Debug.assert((node.transformFlags & TransformFlags.ContainsSpreadElementExpression) !== 0);
+            Debug.assert((node.transformFlags & TransformFlags.ContainsSpreadExpression) !== 0);
 
             // [source]
             //      new C(...a)
@@ -2834,7 +2344,7 @@ namespace ts {
         }
 
         /**
-         * Transforms an array of Expression nodes that contains a SpreadElementExpression.
+         * Transforms an array of Expression nodes that contains a SpreadExpression.
          *
          * @param elements The array of Expression nodes.
          * @param needsUniqueCopy A value indicating whether to ensure that the result is a fresh array.
@@ -2851,14 +2361,14 @@ namespace ts {
             // expressions into an array literal.
             const numElements = elements.length;
             const segments = flatten(
-                spanMap(elements, partitionSpreadElement, (partition, visitPartition, _start, end) =>
+                spanMap(elements, partitionSpread, (partition, visitPartition, _start, end) =>
                     visitPartition(partition, multiLine, hasTrailingComma && end === numElements)
                 )
             );
 
             if (segments.length === 1) {
                 const firstElement = elements[0];
-                return needsUniqueCopy && isSpreadElementExpression(firstElement) && firstElement.expression.kind !== SyntaxKind.ArrayLiteralExpression
+                return needsUniqueCopy && isSpreadExpression(firstElement) && firstElement.expression.kind !== SyntaxKind.ArrayLiteralExpression
                     ? createArraySlice(segments[0])
                     : segments[0];
             }
@@ -2867,17 +2377,17 @@ namespace ts {
             return createArrayConcat(segments.shift(), segments);
         }
 
-        function partitionSpreadElement(node: Expression) {
-            return isSpreadElementExpression(node)
-                ? visitSpanOfSpreadElements
-                : visitSpanOfNonSpreadElements;
+        function partitionSpread(node: Expression) {
+            return isSpreadExpression(node)
+                ? visitSpanOfSpreads
+                : visitSpanOfNonSpreads;
         }
 
-        function visitSpanOfSpreadElements(chunk: Expression[]): VisitResult<Expression> {
-            return map(chunk, visitExpressionOfSpreadElement);
+        function visitSpanOfSpreads(chunk: Expression[]): VisitResult<Expression> {
+            return map(chunk, visitExpressionOfSpread);
         }
 
-        function visitSpanOfNonSpreadElements(chunk: Expression[], multiLine: boolean, hasTrailingComma: boolean): VisitResult<Expression> {
+        function visitSpanOfNonSpreads(chunk: Expression[], multiLine: boolean, hasTrailingComma: boolean): VisitResult<Expression> {
             return createArrayLiteral(
                 visitNodes(createNodeArray(chunk, /*location*/ undefined, hasTrailingComma), visitor, isExpression),
                 /*location*/ undefined,
@@ -2886,11 +2396,11 @@ namespace ts {
         }
 
         /**
-         * Transforms the expression of a SpreadElementExpression node.
+         * Transforms the expression of a SpreadExpression node.
          *
-         * @param node A SpreadElementExpression node.
+         * @param node A SpreadExpression node.
          */
-        function visitExpressionOfSpreadElement(node: SpreadElementExpression) {
+        function visitExpressionOfSpread(node: SpreadElement) {
             return visitNode(node.expression, visitor, isExpression);
         }
 
@@ -3076,7 +2586,7 @@ namespace ts {
             const statements: Statement[] = [];
             startLexicalEnvironment();
             addRange(statements, prologue);
-            addCaptureThisForNodeIfNeeded(statements, node);
+            addCaptureThisForNodeIfNeeded(statements, node, enableSubstitutionsForCapturedThis);
             addRange(statements, visitNodes(createNodeArray(remaining), visitor, isStatement));
             addRange(statements, endLexicalEnvironment());
             const clone = getMutableClone(node);
@@ -3266,11 +2776,11 @@ namespace ts {
             }
 
             const callArgument = singleOrUndefined((<CallExpression>statementExpression).arguments);
-            if (!callArgument || !nodeIsSynthesized(callArgument) || callArgument.kind !== SyntaxKind.SpreadElementExpression) {
+            if (!callArgument || !nodeIsSynthesized(callArgument) || callArgument.kind !== SyntaxKind.SpreadElement) {
                 return false;
             }
 
-            const expression = (<SpreadElementExpression>callArgument).expression;
+            const expression = (<SpreadElement>callArgument).expression;
             return isIdentifier(expression) && expression === parameter.name;
         }
     }

src/compiler/transformers/es2016.ts

@@ -32,7 +32,6 @@ namespace ts {
             switch (node.kind) {
                 case SyntaxKind.BinaryExpression:
                     return visitBinaryExpression(<BinaryExpression>node);
-
                 default:
                     Debug.failBadSyntaxKind(node);
                     return visitEachChild(node, visitor, context);

src/compiler/transformers/esnext.ts

@@ -0,0 +1,272 @@
+/// <reference path="../factory.ts" />
+/// <reference path="../visitor.ts" />
+
+/*@internal*/
+namespace ts {
+    export function transformESNext(context: TransformationContext) {
+        const {
+            hoistVariableDeclaration,
+        } = context;
+        let currentSourceFile: SourceFile;
+        return transformSourceFile;
+
+        function transformSourceFile(node: SourceFile) {
+            currentSourceFile = node;
+            return visitEachChild(node, visitor, context);
+        }
+
+        function visitor(node: Node): VisitResult<Node> {
+            if (node.transformFlags & TransformFlags.ESNext) {
+                return visitorWorker(node);
+            }
+            else if (node.transformFlags & TransformFlags.ContainsESNext) {
+                return visitEachChild(node, visitor, context);
+            }
+            else {
+                return node;
+            }
+        }
+
+        function visitorWorker(node: Node): VisitResult<Node> {
+            switch (node.kind) {
+                case SyntaxKind.ObjectLiteralExpression:
+                    return visitObjectLiteralExpression(node as ObjectLiteralExpression);
+                case SyntaxKind.BinaryExpression:
+                    return visitBinaryExpression(node as BinaryExpression);
+                case SyntaxKind.VariableDeclaration:
+                    return visitVariableDeclaration(node as VariableDeclaration);
+                case SyntaxKind.ForOfStatement:
+                    return visitForOfStatement(node as ForOfStatement);
+                case SyntaxKind.ObjectBindingPattern:
+                case SyntaxKind.ArrayBindingPattern:
+                    return node;
+                case SyntaxKind.FunctionDeclaration:
+                    return visitFunctionDeclaration(node as FunctionDeclaration);
+                case SyntaxKind.FunctionExpression:
+                    return visitFunctionExpression(node as FunctionExpression);
+                case SyntaxKind.ArrowFunction:
+                    return visitArrowFunction(node as ArrowFunction);
+                case SyntaxKind.Parameter:
+                    return visitParameter(node as ParameterDeclaration);
+                default:
+                    Debug.failBadSyntaxKind(node);
+                    return visitEachChild(node, visitor, context);
+            }
+        }
+
+        function chunkObjectLiteralElements(elements: ObjectLiteralElement[]): Expression[] {
+            let chunkObject: (ShorthandPropertyAssignment | PropertyAssignment)[];
+            const objects: Expression[] = [];
+            for (const e of elements) {
+                if (e.kind === SyntaxKind.SpreadAssignment) {
+                    if (chunkObject) {
+                        objects.push(createObjectLiteral(chunkObject));
+                        chunkObject = undefined;
+                    }
+                    const target = (e as SpreadAssignment).expression;
+                    objects.push(visitNode(target, visitor, isExpression));
+                }
+                else {
+                    if (!chunkObject) {
+                        chunkObject = [];
+                    }
+                    if (e.kind === SyntaxKind.PropertyAssignment) {
+                        const p = e as PropertyAssignment;
+                        chunkObject.push(createPropertyAssignment(p.name, visitNode(p.initializer, visitor, isExpression)));
+                    }
+                    else {
+                        chunkObject.push(e as ShorthandPropertyAssignment);
+                    }
+                }
+            }
+            if (chunkObject) {
+                objects.push(createObjectLiteral(chunkObject));
+            }
+
+            return objects;
+        }
+
+        function visitObjectLiteralExpression(node: ObjectLiteralExpression): Expression {
+            // spread elements emit like so:
+            // non-spread elements are chunked together into object literals, and then all are passed to __assign:
+            //     { a, ...o, b } => __assign({a}, o, {b});
+            // If the first element is a spread element, then the first argument to __assign is {}:
+            //     { ...o, a, b, ...o2 } => __assign({}, o, {a, b}, o2)
+            const objects = chunkObjectLiteralElements(node.properties);
+            if (objects.length && objects[0].kind !== SyntaxKind.ObjectLiteralExpression) {
+                objects.unshift(createObjectLiteral());
+            }
+            return createCall(createIdentifier("__assign"), undefined, objects);
+        }
+
+        /**
+         * Visits a BinaryExpression that contains a destructuring assignment.
+         *
+         * @param node A BinaryExpression node.
+         */
+        function visitBinaryExpression(node: BinaryExpression): Expression {
+            if (isDestructuringAssignment(node) && node.left.transformFlags & TransformFlags.AssertESNext) {
+                return flattenDestructuringAssignment(context, node, /*needsDestructuringValue*/ true, hoistVariableDeclaration, visitor, /*transformRest*/ true);
+            }
+
+            return visitEachChild(node, visitor, context);
+        }
+
+        /**
+         * Visits a VariableDeclaration node with a binding pattern.
+         *
+         * @param node A VariableDeclaration node.
+         */
+        function visitVariableDeclaration(node: VariableDeclaration): VisitResult<VariableDeclaration> {
+            // If we are here it is because the name contains a binding pattern with a rest somewhere in it.
+            if (isBindingPattern(node.name) && node.name.transformFlags & TransformFlags.AssertESNext) {
+                const result = flattenVariableDestructuring(node, /*value*/ undefined, visitor, /*recordTempVariable*/ undefined, /*transformRest*/ true);
+                return result;
+            }
+
+            return visitEachChild(node, visitor, context);
+        }
+
+        /**
+         * Visits a ForOfStatement and converts it into a ES2015-compatible ForOfStatement.
+         *
+         * @param node A ForOfStatement.
+         */
+        function visitForOfStatement(node: ForOfStatement): VisitResult<Statement> {
+            // The following ESNext code:
+            //
+            //    for (let { x, y, ...rest } of expr) { }
+            //
+            // should be emitted as
+            //
+            //    for (var _a of expr) {
+            //        let { x, y } = _a, rest = __rest(_a, ["x", "y"]);
+            //    }
+            //
+            // where _a is a temp emitted to capture the RHS.
+            // When the left hand side is an expression instead of a let declaration,
+            // the `let` before the `{ x, y }` is not emitted.
+            // When the left hand side is a let/const, the v is renamed if there is
+            // another v in scope.
+            // Note that all assignments to the LHS are emitted in the body, including
+            // all destructuring.
+            // Note also that because an extra statement is needed to assign to the LHS,
+            // for-of bodies are always emitted as blocks.
+
+            // for (<init> of <expression>) <statement>
+            // where <init> is [let] variabledeclarationlist | expression
+            const initializer = node.initializer;
+            if (!isRestBindingPattern(initializer) && !isRestAssignment(initializer)) {
+                return visitEachChild(node, visitor, context);
+            }
+
+            return convertForOf(node, undefined, visitor, noop, context, /*transformRest*/ true);
+        }
+
+        function isRestBindingPattern(initializer: ForInitializer) {
+            if (isVariableDeclarationList(initializer)) {
+                const declaration = firstOrUndefined(initializer.declarations);
+                return declaration && declaration.name &&
+                    declaration.name.kind === SyntaxKind.ObjectBindingPattern &&
+                    !!(declaration.name.transformFlags & TransformFlags.ContainsSpreadExpression);
+            }
+            return false;
+        }
+
+        function isRestAssignment(initializer: ForInitializer) {
+            return initializer.kind === SyntaxKind.ObjectLiteralExpression &&
+                initializer.transformFlags & TransformFlags.ContainsSpreadExpression;
+        }
+
+        function visitParameter(node: ParameterDeclaration): ParameterDeclaration {
+            if (isObjectRestParameter(node)) {
+                // Binding patterns are converted into a generated name and are
+                // evaluated inside the function body.
+                return setOriginalNode(
+                    createParameter(
+                        /*decorators*/ undefined,
+                        /*modifiers*/ undefined,
+                        /*dotDotDotToken*/ undefined,
+                        getGeneratedNameForNode(node),
+                        /*questionToken*/ undefined,
+                        /*type*/ undefined,
+                        node.initializer,
+                        /*location*/ node
+                    ),
+                    /*original*/ node
+                );
+            }
+            else {
+                return node;
+            }
+        }
+
+        function isObjectRestParameter(node: ParameterDeclaration) {
+            return node.name &&
+                node.name.kind === SyntaxKind.ObjectBindingPattern &&
+                !!(node.name.transformFlags & TransformFlags.ContainsSpreadExpression);
+        }
+
+        function visitFunctionDeclaration(node: FunctionDeclaration): FunctionDeclaration {
+            const hasRest = forEach(node.parameters, isObjectRestParameter);
+            const body = hasRest ?
+                transformFunctionBody(node, visitor, currentSourceFile, context, noop, /*convertObjectRest*/ true) as Block :
+                visitEachChild(node.body, visitor, context);
+
+            return setOriginalNode(
+                createFunctionDeclaration(
+                    /*decorators*/ undefined,
+                    node.modifiers,
+                    node.asteriskToken,
+                    node.name,
+                    /*typeParameters*/ undefined,
+                    visitNodes(node.parameters, visitor, isParameter),
+                    /*type*/ undefined,
+                    body,
+                    /*location*/ node
+                ),
+                /*original*/ node);
+        }
+
+        function visitArrowFunction(node: ArrowFunction) {
+            const hasRest = forEach(node.parameters, isObjectRestParameter);
+            const body = hasRest ?
+                transformFunctionBody(node, visitor, currentSourceFile, context, noop, /*convertObjectRest*/ true) as Block :
+                visitEachChild(node.body, visitor, context);
+            const func = setOriginalNode(
+                createArrowFunction(
+                    /*modifiers*/ undefined,
+                    /*typeParameters*/ undefined,
+                    visitNodes(node.parameters, visitor, isParameter),
+                    /*type*/ undefined,
+                    node.equalsGreaterThanToken,
+                    body,
+                    /*location*/ node
+                ),
+                /*original*/ node
+            );
+            setEmitFlags(func, EmitFlags.CapturesThis);
+            return func;
+        }
+
+        function visitFunctionExpression(node: FunctionExpression): Expression {
+            const hasRest = forEach(node.parameters, isObjectRestParameter);
+            const body = hasRest ?
+                transformFunctionBody(node, visitor, currentSourceFile, context, noop, /*convertObjectRest*/ true) as Block :
+                visitEachChild(node.body, visitor, context);
+            return setOriginalNode(
+                createFunctionExpression(
+                    /*modifiers*/ undefined,
+                    node.asteriskToken,
+                    name,
+                    /*typeParameters*/ undefined,
+                    visitNodes(node.parameters, visitor, isParameter),
+                    /*type*/ undefined,
+                    body,
+                    /*location*/ node
+                ),
+                /*original*/ node
+            );
+        }
+    }
+}

src/compiler/transformers/jsx.ts

@@ -113,7 +113,8 @@ namespace ts {
                     || createAssignHelper(currentSourceFile.externalHelpersModuleName, segments);
             }
 
-            const element = createReactCreateElement(
+            const element = createExpressionForJsxElement(
+                context.getEmitResolver().getJsxFactoryEntity(),
                 compilerOptions.reactNamespace,
                 tagName,
                 objectProperties,

src/compiler/transformers/module/system.ts

@@ -1474,7 +1474,7 @@ namespace ts {
             if (isAssignmentExpression(node)) {
                 return hasExportedReferenceInDestructuringTarget(node.left);
             }
-            else if (isSpreadElementExpression(node)) {
+            else if (isSpreadExpression(node)) {
                 return hasExportedReferenceInDestructuringTarget(node.expression);
             }
             else if (isObjectLiteralExpression(node)) {

src/compiler/tsconfig.json

@@ -27,6 +27,7 @@
         "visitor.ts",
         "transformers/ts.ts",
         "transformers/jsx.ts",
+        "transformers/esnext.ts",
         "transformers/es2017.ts",
         "transformers/es2016.ts",
         "transformers/es2015.ts",

src/compiler/types.ts

@@ -247,7 +247,7 @@ namespace ts {
         ConditionalExpression,
         TemplateExpression,
         YieldExpression,
-        SpreadElementExpression,
+        SpreadElement,
         ClassExpression,
         OmittedExpression,
         ExpressionWithTypeArguments,
@@ -321,6 +321,7 @@ namespace ts {
         // Property assignments
         PropertyAssignment,
         ShorthandPropertyAssignment,
+        SpreadAssignment,
 
         // Enum
         EnumMember,
@@ -419,20 +420,21 @@ namespace ts {
         HasDecorators =      1 << 11, // If the file has decorators (initialized by binding)
         HasParamDecorators = 1 << 12, // If the file has parameter decorators (initialized by binding)
         HasAsyncFunctions =  1 << 13, // If the file has async functions (initialized by binding)
-        HasJsxSpreadAttributes = 1 << 14, // If the file as JSX spread attributes (initialized by binding)
-        DisallowInContext =  1 << 15, // If node was parsed in a context where 'in-expressions' are not allowed
-        YieldContext =       1 << 16, // If node was parsed in the 'yield' context created when parsing a generator
-        DecoratorContext =   1 << 17, // If node was parsed as part of a decorator
-        AwaitContext =       1 << 18, // If node was parsed in the 'await' context created when parsing an async function
-        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
+        HasSpreadAttribute = 1 << 14, // If the file as JSX spread attributes (initialized by binding)
+        HasRestAttribute =   1 << 15, // If the file has object destructure elements
+        DisallowInContext =  1 << 16, // If node was parsed in a context where 'in-expressions' are not allowed
+        YieldContext =       1 << 17, // If node was parsed in the 'yield' context created when parsing a generator
+        DecoratorContext =   1 << 18, // If node was parsed as part of a decorator
+        AwaitContext =       1 << 19, // If node was parsed in the 'await' context created when parsing an async function
+        ThisNodeHasError =   1 << 20, // If the parser encountered an error when parsing the code that created this node
+        JavaScriptFile =     1 << 21, // If node was parsed in a JavaScript
+        ThisNodeOrAnySubNodesHasError = 1 << 22, // If this node or any of its children had an error
+        HasAggregatedChildData = 1 << 23, // If we've computed data from children and cached it in this node
 
         BlockScoped = Let | Const,
 
         ReachabilityCheckFlags = HasImplicitReturn | HasExplicitReturn,
-        EmitHelperFlags = HasClassExtends | HasDecorators | HasParamDecorators | HasAsyncFunctions | HasJsxSpreadAttributes,
+        EmitHelperFlags = HasClassExtends | HasDecorators | HasParamDecorators | HasAsyncFunctions | HasSpreadAttribute,
         ReachabilityAndEmitFlags = ReachabilityCheckFlags | EmitHelperFlags,
 
         // Parsing context flags
@@ -455,7 +457,6 @@ namespace ts {
         Async =              1 << 8,  // Property/Method/Function
         Default =            1 << 9,  // Function/Class (export default declaration)
         Const =              1 << 11, // Variable declaration
-
         HasComputedFlags =   1 << 29, // Modifier flags have been computed
 
         AccessibilityModifier = Public | Private | Protected,
@@ -651,7 +652,7 @@ namespace ts {
     export interface BindingElement extends Declaration {
         kind: SyntaxKind.BindingElement;
         propertyName?: PropertyName;        // Binding property name (in object binding pattern)
-        dotDotDotToken?: DotDotDotToken;              // Present on rest binding element
+        dotDotDotToken?: DotDotDotToken;    // Present on rest element (in object binding pattern)
         name: BindingName;                  // Declared binding element name
         initializer?: Expression;           // Optional initializer
     }
@@ -677,7 +678,7 @@ namespace ts {
         name?: PropertyName;
     }
 
-    export type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration;
+    export type ObjectLiteralElementLike = PropertyAssignment | ShorthandPropertyAssignment | MethodDeclaration | AccessorDeclaration | SpreadAssignment;
 
     export interface PropertyAssignment extends ObjectLiteralElement {
         kind: SyntaxKind.PropertyAssignment;
@@ -696,6 +697,11 @@ namespace ts {
         objectAssignmentInitializer?: Expression;
     }
 
+    export interface SpreadAssignment extends ObjectLiteralElement {
+        kind: SyntaxKind.SpreadAssignment;
+        expression: Expression;
+    }
+
     // SyntaxKind.VariableDeclaration
     // SyntaxKind.Parameter
     // SyntaxKind.BindingElement
@@ -1289,8 +1295,8 @@ namespace ts {
         multiLine?: boolean;
     }
 
-    export interface SpreadElementExpression extends Expression {
-        kind: SyntaxKind.SpreadElementExpression;
+    export interface SpreadElement extends Expression {
+        kind: SyntaxKind.SpreadElement;
         expression: Expression;
     }
 
@@ -2391,6 +2397,12 @@ namespace ts {
         CannotBeNamed
     }
 
+    /* @internal */
+    export const enum SyntheticSymbolKind {
+        UnionOrIntersection,
+        Spread
+    }
+
     export const enum TypePredicateKind {
         This,
         Identifier
@@ -2483,6 +2495,7 @@ namespace ts {
         getTypeReferenceDirectivesForSymbol(symbol: Symbol, meaning?: SymbolFlags): string[];
         isLiteralConstDeclaration(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration): boolean;
         writeLiteralConstValue(node: VariableDeclaration | PropertyDeclaration | PropertySignature | ParameterDeclaration, writer: SymbolWriter): void;
+        getJsxFactoryEntity(): EntityName;
     }
 
     export const enum SymbolFlags {
@@ -2602,7 +2615,9 @@ namespace ts {
         instantiations?: Map<Type>;         // Instantiations of generic type alias (undefined if non-generic)
         mapper?: TypeMapper;                // Type mapper for instantiation alias
         referenced?: boolean;               // True if alias symbol has been referenced as a value
-        containingType?: UnionOrIntersectionType; // Containing union or intersection type for synthetic property
+        containingType?: UnionOrIntersectionType;  // Containing union or intersection type for synthetic property
+        leftSpread?: Symbol;                // Left source for synthetic spread property
+        rightSpread?: Symbol;               // Right source for synthetic spread property
         hasNonUniformType?: boolean;        // True if constituents have non-uniform types
         isPartial?: boolean;                // True if syntheric property of union type occurs in some but not all constituents
         isDiscriminantProperty?: boolean;   // True if discriminant synthetic property
@@ -3101,6 +3116,7 @@ namespace ts {
         project?: string;
         /* @internal */ pretty?: DiagnosticStyle;
         reactNamespace?: string;
+        jsxFactory?: string;
         removeComments?: boolean;
         rootDir?: string;
         rootDirs?: string[];
@@ -3183,7 +3199,8 @@ namespace ts {
         ES2015 = 2,
         ES2016 = 3,
         ES2017 = 4,
-        Latest = ES2017,
+        ESNext = 5,
+        Latest = ESNext,
     }
 
     export const enum LanguageVariant {
@@ -3498,32 +3515,34 @@ namespace ts {
         ContainsTypeScript = 1 << 1,
         Jsx = 1 << 2,
         ContainsJsx = 1 << 3,
-        ES2017 = 1 << 4,
-        ContainsES2017 = 1 << 5,
-        ES2016 = 1 << 6,
-        ContainsES2016 = 1 << 7,
-        ES2015 = 1 << 8,
-        ContainsES2015 = 1 << 9,
-        Generator = 1 << 10,
-        ContainsGenerator = 1 << 11,
-        DestructuringAssignment = 1 << 12,
-        ContainsDestructuringAssignment = 1 << 13,
+        ESNext = 1 << 4,
+        ContainsESNext = 1 << 5,
+        ES2017 = 1 << 6,
+        ContainsES2017 = 1 << 7,
+        ES2016 = 1 << 8,
+        ContainsES2016 = 1 << 9,
+        ES2015 = 1 << 10,
+        ContainsES2015 = 1 << 11,
+        Generator = 1 << 12,
+        ContainsGenerator = 1 << 13,
+        DestructuringAssignment = 1 << 14,
+        ContainsDestructuringAssignment = 1 << 15,
 
         // Markers
         // - Flags used to indicate that a subtree contains a specific transformation.
-        ContainsDecorators = 1 << 14,
-        ContainsPropertyInitializer = 1 << 15,
-        ContainsLexicalThis = 1 << 16,
-        ContainsCapturedLexicalThis = 1 << 17,
-        ContainsLexicalThisInComputedPropertyName = 1 << 18,
-        ContainsDefaultValueAssignments = 1 << 19,
-        ContainsParameterPropertyAssignments = 1 << 20,
-        ContainsSpreadElementExpression = 1 << 21,
-        ContainsComputedPropertyName = 1 << 22,
-        ContainsBlockScopedBinding = 1 << 23,
-        ContainsBindingPattern = 1 << 24,
-        ContainsYield = 1 << 25,
-        ContainsHoistedDeclarationOrCompletion = 1 << 26,
+        ContainsDecorators = 1 << 16,
+        ContainsPropertyInitializer = 1 << 17,
+        ContainsLexicalThis = 1 << 18,
+        ContainsCapturedLexicalThis = 1 << 19,
+        ContainsLexicalThisInComputedPropertyName = 1 << 20,
+        ContainsDefaultValueAssignments = 1 << 21,
+        ContainsParameterPropertyAssignments = 1 << 22,
+        ContainsSpreadExpression = 1 << 23,
+        ContainsComputedPropertyName = 1 << 24,
+        ContainsBlockScopedBinding = 1 << 25,
+        ContainsBindingPattern = 1 << 26,
+        ContainsYield = 1 << 27,
+        ContainsHoistedDeclarationOrCompletion = 1 << 28,
 
         HasComputedFlags = 1 << 29, // Transform flags have been computed.
 
@@ -3531,6 +3550,7 @@ namespace ts {
         // - Bitmasks that are used to assert facts about the syntax of a node and its subtree.
         AssertTypeScript = TypeScript | ContainsTypeScript,
         AssertJsx = Jsx | ContainsJsx,
+        AssertESNext = ESNext | ContainsESNext,
         AssertES2017 = ES2017 | ContainsES2017,
         AssertES2016 = ES2016 | ContainsES2016,
         AssertES2015 = ES2015 | ContainsES2015,
@@ -3540,7 +3560,7 @@ namespace ts {
         // Scope Exclusions
         // - Bitmasks that exclude flags from propagating out of a specific context
         //   into the subtree flags of their container.
-        NodeExcludes = TypeScript | Jsx | ES2017 | ES2016 | ES2015 | DestructuringAssignment | Generator | HasComputedFlags,
+        NodeExcludes = TypeScript | Jsx | ESNext | ES2017 | ES2016 | ES2015 | DestructuringAssignment | Generator | HasComputedFlags,
         ArrowFunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
         FunctionExcludes = NodeExcludes | ContainsDecorators | ContainsDefaultValueAssignments | ContainsCapturedLexicalThis | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
         ConstructorExcludes = NodeExcludes | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsYield | ContainsHoistedDeclarationOrCompletion,
@@ -3549,7 +3569,7 @@ namespace ts {
         ModuleExcludes = NodeExcludes | ContainsDecorators | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding | ContainsHoistedDeclarationOrCompletion,
         TypeExcludes = ~ContainsTypeScript,
         ObjectLiteralExcludes = NodeExcludes | ContainsDecorators | ContainsComputedPropertyName | ContainsLexicalThisInComputedPropertyName,
-        ArrayLiteralOrCallOrNewExcludes = NodeExcludes | ContainsSpreadElementExpression,
+        ArrayLiteralOrCallOrNewExcludes = NodeExcludes | ContainsSpreadExpression,
         VariableDeclarationListExcludes = NodeExcludes | ContainsBindingPattern,
         ParameterExcludes = NodeExcludes | ContainsBindingPattern,
 

src/compiler/utilities.ts

@@ -485,6 +485,22 @@ namespace ts {
         return getFullWidth(name) === 0 ? "(Missing)" : getTextOfNode(name);
     }
 
+    export function getTextOfPropertyName(name: PropertyName): string {
+        switch (name.kind) {
+        case SyntaxKind.Identifier:
+            return (<Identifier>name).text;
+        case SyntaxKind.StringLiteral:
+        case SyntaxKind.NumericLiteral:
+            return (<LiteralExpression>name).text;
+        case SyntaxKind.ComputedPropertyName:
+            if (isStringOrNumericLiteral((<ComputedPropertyName>name).expression.kind)) {
+                return (<LiteralExpression>(<ComputedPropertyName>name).expression).text;
+            }
+        }
+
+        return undefined;
+    }
+
     export function entityNameToString(name: EntityNameOrEntityNameExpression): string {
         switch (name.kind) {
             case SyntaxKind.Identifier:
@@ -498,6 +514,10 @@ namespace ts {
 
     export function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
         const sourceFile = getSourceFileOfNode(node);
+        return createDiagnosticForNodeInSourceFile(sourceFile, node, message, arg0, arg1, arg2);
+    }
+
+    export function createDiagnosticForNodeInSourceFile(sourceFile: SourceFile, node: Node, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number): Diagnostic {
         const span = getErrorSpanForNode(sourceFile, node);
         return createFileDiagnostic(sourceFile, span.start, span.length, message, arg0, arg1, arg2);
     }
@@ -1179,7 +1199,7 @@ namespace ts {
             case SyntaxKind.PostfixUnaryExpression:
             case SyntaxKind.BinaryExpression:
             case SyntaxKind.ConditionalExpression:
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadElement:
             case SyntaxKind.TemplateExpression:
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.OmittedExpression:
@@ -1641,7 +1661,7 @@ namespace ts {
                     return (<ForInStatement | ForOfStatement>parent).initializer === node ? AssignmentKind.Definite : AssignmentKind.None;
                 case SyntaxKind.ParenthesizedExpression:
                 case SyntaxKind.ArrayLiteralExpression:
-                case SyntaxKind.SpreadElementExpression:
+                case SyntaxKind.SpreadElement:
                     node = parent;
                     break;
                 case SyntaxKind.ShorthandPropertyAssignment:
@@ -2226,7 +2246,7 @@ namespace ts {
             case SyntaxKind.YieldExpression:
                 return 2;
 
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadElement:
                 return 1;
 
             default:
@@ -3862,6 +3882,7 @@ namespace ts {
         const kind = node.kind;
         return kind === SyntaxKind.PropertyAssignment
             || kind === SyntaxKind.ShorthandPropertyAssignment
+            || kind === SyntaxKind.SpreadAssignment
             || kind === SyntaxKind.MethodDeclaration
             || kind === SyntaxKind.GetAccessor
             || kind === SyntaxKind.SetAccessor
@@ -3949,8 +3970,8 @@ namespace ts {
             || kind === SyntaxKind.NoSubstitutionTemplateLiteral;
     }
 
-    export function isSpreadElementExpression(node: Node): node is SpreadElementExpression {
-        return node.kind === SyntaxKind.SpreadElementExpression;
+    export function isSpreadExpression(node: Node): node is SpreadElement {
+        return node.kind === SyntaxKind.SpreadElement;
     }
 
     export function isExpressionWithTypeArguments(node: Node): node is ExpressionWithTypeArguments {
@@ -4008,7 +4029,7 @@ namespace ts {
             || kind === SyntaxKind.YieldExpression
             || kind === SyntaxKind.ArrowFunction
             || kind === SyntaxKind.BinaryExpression
-            || kind === SyntaxKind.SpreadElementExpression
+            || kind === SyntaxKind.SpreadElement
             || kind === SyntaxKind.AsExpression
             || kind === SyntaxKind.OmittedExpression
             || isUnaryExpressionKind(kind);
@@ -4310,6 +4331,7 @@ namespace ts {
 namespace ts {
     export function getDefaultLibFileName(options: CompilerOptions): string {
         switch (options.target) {
+            case ScriptTarget.ESNext:
             case ScriptTarget.ES2017:
                 return "lib.es2017.d.ts";
             case ScriptTarget.ES2016:

src/compiler/visitor.ts

@@ -267,9 +267,9 @@ namespace ts {
             case SyntaxKind.VoidExpression:
             case SyntaxKind.AwaitExpression:
             case SyntaxKind.YieldExpression:
-            case SyntaxKind.SpreadElementExpression:
+            case SyntaxKind.SpreadElement:
             case SyntaxKind.NonNullExpression:
-                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadElementExpression | NonNullExpression>node).expression, f, result);
+                result = reduceNode((<ParenthesizedExpression | DeleteExpression | TypeOfExpression | VoidExpression | AwaitExpression | YieldExpression | SpreadElement | NonNullExpression>node).expression, f, result);
                 break;
 
             case SyntaxKind.PrefixUnaryExpression:
@@ -510,6 +510,10 @@ namespace ts {
                 result = reduceNode((<ShorthandPropertyAssignment>node).objectAssignmentInitializer, f, result);
                 break;
 
+            case SyntaxKind.SpreadAssignment:
+                result = reduceNode((node as SpreadAssignment).expression, f, result);
+                break;
+
             // Top-level nodes
             case SyntaxKind.SourceFile:
                 result = reduceLeft((<SourceFile>node).statements, f, result);
@@ -872,9 +876,9 @@ namespace ts {
                 return updateYield(<YieldExpression>node,
                     visitNode((<YieldExpression>node).expression, visitor, isExpression));
 
-            case SyntaxKind.SpreadElementExpression:
-                return updateSpread(<SpreadElementExpression>node,
-                    visitNode((<SpreadElementExpression>node).expression, visitor, isExpression));
+            case SyntaxKind.SpreadElement:
+                return updateSpread(<SpreadElement>node,
+                    visitNode((<SpreadElement>node).expression, visitor, isExpression));
 
             case SyntaxKind.ClassExpression:
                 return updateClassExpression(<ClassExpression>node,
@@ -1127,7 +1131,11 @@ namespace ts {
                     visitNode((<ShorthandPropertyAssignment>node).name, visitor, isIdentifier),
                     visitNode((<ShorthandPropertyAssignment>node).objectAssignmentInitializer, visitor, isExpression));
 
-            // Top-level nodes
+            case SyntaxKind.SpreadAssignment:
+                return updateSpreadAssignment(node as SpreadAssignment,
+                    visitNode((node as SpreadAssignment).expression, visitor, isExpression));
+
+           // Top-level nodes
             case SyntaxKind.SourceFile:
                 context.startLexicalEnvironment();
                 return updateSourceFileNode(<SourceFile>node,

src/harness/fourslash.ts

@@ -1026,7 +1026,7 @@ namespace FourSlash {
                 ts.displayPartsToString(help.suffixDisplayParts), expected);
         }
 
-        public verifyCurrentParameterIsletiable(isVariable: boolean) {
+        public verifyCurrentParameterIsVariable(isVariable: boolean) {
             const signature = this.getActiveSignatureHelpItem();
             assert.isOk(signature);
             assert.equal(isVariable, signature.isVariadic);
@@ -1053,6 +1053,10 @@ namespace FourSlash {
             assert.equal(this.getActiveSignatureHelpItem().parameters.length, expectedCount);
         }
 
+        public verifyCurrentSignatureHelpIsVariadic(expected: boolean) {
+            assert.equal(this.getActiveSignatureHelpItem().isVariadic, expected);
+        }
+
         public verifyCurrentSignatureHelpDocComment(docComment: string) {
             const actualDocComment = this.getActiveSignatureHelpItem().documentation;
             assert.equal(ts.displayPartsToString(actualDocComment), docComment, this.assertionMessageAtLastKnownMarker("current signature help doc comment"));
@@ -3231,6 +3235,10 @@ namespace FourSlashInterface {
             this.state.verifySignatureHelpCount(expected);
         }
 
+        public signatureHelpCurrentArgumentListIsVariadic(expected: boolean) {
+            this.state.verifyCurrentSignatureHelpIsVariadic(expected);
+        }
+
         public signatureHelpArgumentCountIs(expected: number) {
             this.state.verifySignatureHelpArgumentCount(expected);
         }

src/harness/harness.ts

@@ -1483,7 +1483,7 @@ namespace Harness {
             }
 
             if (typesError && symbolsError) {
-                throw new Error(typesError.message + ts.sys.newLine + symbolsError.message);
+                throw new Error(typesError.message + Harness.IO.newLine() + symbolsError.message);
             }
 
             if (typesError) {
@@ -1768,7 +1768,7 @@ namespace Harness {
         }
 
         // Regex for parsing options in the format "@Alpha: Value of any sort"
-        const optionRegex = /^[\/]{2}\s*@(\w+)\s*:\s*(\S*)/gm;  // multiple matches on multiple lines
+        const optionRegex = /^[\/]{2}\s*@(\w+)\s*:\s*([^\r\n]*)/gm;  // multiple matches on multiple lines
 
         function extractCompilerSettings(content: string): CompilerSettings {
             const opts: CompilerSettings = {};
@@ -1777,7 +1777,7 @@ namespace Harness {
             /* tslint:disable:no-null-keyword */
             while ((match = optionRegex.exec(content)) !== null) {
             /* tslint:enable:no-null-keyword */
-                opts[match[1]] = match[2];
+                opts[match[1]] = match[2].trim();
             }
 
             return opts;
@@ -1805,7 +1805,7 @@ namespace Harness {
                     // Comment line, check for global/file @options and record them
                     optionRegex.lastIndex = 0;
                     const metaDataName = testMetaData[1].toLowerCase();
-                    currentFileOptions[testMetaData[1]] = testMetaData[2];
+                    currentFileOptions[testMetaData[1]] = testMetaData[2].trim();
                     if (metaDataName !== "filename") {
                         continue;
                     }
@@ -1825,12 +1825,12 @@ namespace Harness {
                         // Reset local data
                         currentFileContent = undefined;
                         currentFileOptions = {};
-                        currentFileName = testMetaData[2];
+                        currentFileName = testMetaData[2].trim();
                         refs = [];
                     }
                     else {
                         // First metadata marker in the file
-                        currentFileName = testMetaData[2];
+                        currentFileName = testMetaData[2].trim();
                     }
                 }
                 else {

src/harness/harnessLanguageService.ts

@@ -720,6 +720,10 @@ namespace Harness.LanguageService {
         clearImmediate(timeoutId: any): void {
             clearImmediate(timeoutId);
         }
+
+        createHash(s: string) {
+            return s;
+        }
     }
 
     export class ServerLanguageServiceAdapter implements LanguageServiceAdapter {

src/harness/tsconfig.json

@@ -29,6 +29,7 @@
         "../compiler/visitor.ts",
         "../compiler/transformers/ts.ts",
         "../compiler/transformers/jsx.ts",
+        "../compiler/transformers/esnext.ts",
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
         "../compiler/transformers/es2015.ts",

src/harness/unittests/cachingInServerLSHost.ts

@@ -43,7 +43,8 @@ namespace ts {
             setTimeout,
             clearTimeout,
             setImmediate: typeof setImmediate !== "undefined" ? setImmediate : action => setTimeout(action, 0),
-            clearImmediate: typeof clearImmediate !== "undefined" ? clearImmediate : clearTimeout
+            clearImmediate: typeof clearImmediate !== "undefined" ? clearImmediate : clearTimeout,
+            createHash: s => s
         };
     }
 

src/harness/unittests/commandLineParsing.ts

@@ -165,7 +165,7 @@ namespace ts {
                         start: undefined,
                         length: undefined,
                     }, {
-                            messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017'",
+                            messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017', 'esnext'",
                             category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                             code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 

src/harness/unittests/convertCompilerOptionsFromJson.ts

@@ -176,7 +176,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017'",
+                        messageText: "Argument for '--target' option must be: 'es3', 'es5', 'es6', 'es2015', 'es2016', 'es2017', 'esnext'",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]

src/harness/unittests/session.ts

@@ -24,7 +24,8 @@ namespace ts.server {
         setTimeout() { return 0; },
         clearTimeout: noop,
         setImmediate: () => 0,
-        clearImmediate: noop
+        clearImmediate: noop,
+        createHash: s => s
     };
     const nullCancellationToken: HostCancellationToken = { isCancellationRequested: () => false };
     const mockLogger: Logger = {

src/harness/unittests/transpile.ts

@@ -385,6 +385,10 @@ var x = 0;`, {
             options: { compilerOptions: { reactNamespace: "react" }, fileName: "input.js", reportDiagnostics: true }
         });
 
+        transpilesCorrectly("Supports setting 'jsxFactory'", "x;", {
+            options: { compilerOptions: { jsxFactory: "createElement" }, fileName: "input.js", reportDiagnostics: true }
+        });
+
         transpilesCorrectly("Supports setting 'removeComments'", "x;", {
             options: { compilerOptions: { removeComments: true }, fileName: "input.js", reportDiagnostics: true }
         });

src/harness/unittests/tsserverProjectSystem.ts

@@ -434,6 +434,10 @@ namespace ts.projectSystem {
             };
         }
 
+        createHash(s: string): string {
+            return s;
+        }
+
         triggerDirectoryWatcherCallback(directoryName: string, fileName: string): void {
             const path = this.toPath(directoryName);
             const callbacks = this.watchedDirectories[path];

src/server/builder.ts

@@ -5,15 +5,6 @@
 
 namespace ts.server {
 
-    interface Hash {
-        update(data: any, input_encoding?: string): Hash;
-        digest(encoding: string): any;
-    }
-
-    const crypto: {
-        createHash(algorithm: string): Hash
-    } = require("crypto");
-
     export function shouldEmitFile(scriptInfo: ScriptInfo) {
         return !scriptInfo.hasMixedContent;
     }
@@ -49,9 +40,7 @@ namespace ts.server {
         }
 
         private computeHash(text: string): string {
-            return crypto.createHash("md5")
-                .update(text)
-                .digest("base64");
+            return this.project.projectService.host.createHash(text);
         }
 
         private getSourceFile(): SourceFile {

src/server/editorServices.ts

@@ -250,6 +250,8 @@ namespace ts.server {
             readonly typingsInstaller: ITypingsInstaller = nullTypingsInstaller,
             private readonly eventHandler?: ProjectServiceEventHandler) {
 
+            Debug.assert(!!host.createHash, "'ServerHost.createHash' is required for ProjectService");
+
             this.toCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames);
             this.directoryWatchers = new DirectoryWatchers(this);
             this.throttledOperations = new ThrottledOperations(host);

src/services/breakpoints.ts

@@ -264,7 +264,7 @@ namespace ts.BreakpointResolver {
                         // a or ...c  or d: x from
                         // [a, b, ...c] or { a, b } or { d: x } from destructuring pattern
                         if ((node.kind === SyntaxKind.Identifier ||
-                            node.kind == SyntaxKind.SpreadElementExpression ||
+                            node.kind == SyntaxKind.SpreadElement ||
                             node.kind === SyntaxKind.PropertyAssignment ||
                             node.kind === SyntaxKind.ShorthandPropertyAssignment) &&
                             isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {

src/services/signatureHelp.ts

@@ -557,7 +557,9 @@ namespace ts.SignatureHelp {
                 addRange(prefixDisplayParts, callTargetDisplayParts);
             }
 
+            let isVariadic: boolean;
             if (isTypeParameterList) {
+                isVariadic = false; // type parameter lists are not variadic
                 prefixDisplayParts.push(punctuationPart(SyntaxKind.LessThanToken));
                 const typeParameters = candidateSignature.typeParameters;
                 signatureHelpParameters = typeParameters && typeParameters.length > 0 ? map(typeParameters, createSignatureHelpParameterForTypeParameter) : emptyArray;
@@ -567,6 +569,7 @@ namespace ts.SignatureHelp {
                 addRange(suffixDisplayParts, parameterParts);
             }
             else {
+                isVariadic = candidateSignature.hasRestParameter;
                 const typeParameterParts = mapToDisplayParts(writer =>
                     typeChecker.getSymbolDisplayBuilder().buildDisplayForTypeParametersAndDelimiters(candidateSignature.typeParameters, writer, invocation));
                 addRange(prefixDisplayParts, typeParameterParts);
@@ -582,7 +585,7 @@ namespace ts.SignatureHelp {
             addRange(suffixDisplayParts, returnTypeParts);
 
             return {
-                isVariadic: candidateSignature.hasRestParameter,
+                isVariadic,
                 prefixDisplayParts,
                 suffixDisplayParts,
                 separatorDisplayParts: [punctuationPart(SyntaxKind.CommaToken), spacePart()],

src/services/tsconfig.json

@@ -28,6 +28,7 @@
         "../compiler/visitor.ts",
         "../compiler/transformers/ts.ts",
         "../compiler/transformers/jsx.ts",
+        "../compiler/transformers/esnext.ts",
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
         "../compiler/transformers/es2015.ts",

src/services/utilities.ts

@@ -530,8 +530,8 @@ namespace ts {
             case SyntaxKind.DeleteExpression:
             case SyntaxKind.VoidExpression:
             case SyntaxKind.YieldExpression:
-            case SyntaxKind.SpreadElementExpression:
-                const unaryWordExpression = (<TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadElementExpression>n);
+            case SyntaxKind.SpreadElement:
+                const unaryWordExpression = n as (TypeOfExpression | DeleteExpression | VoidExpression | YieldExpression | SpreadElement);
                 return isCompletedNode(unaryWordExpression.expression, sourceFile);
 
             case SyntaxKind.TaggedTemplateExpression:

tests/baselines/reference/decoratorInJsFile.errors.txt

@@ -0,0 +1,13 @@
+tests/cases/compiler/a.js(4,12): error TS8010: 'types' can only be used in a .ts file.
+
+
+==== tests/cases/compiler/a.js (1 errors) ====
+    
+    @SomeDecorator
+    class SomeClass {
+        foo(x: number) {
+               ~~~~~~
+!!! error TS8010: 'types' can only be used in a .ts file.
+    
+        }
+    }

tests/baselines/reference/decoratorInJsFile1.errors.txt

@@ -0,0 +1,16 @@
+tests/cases/compiler/a.js(3,7): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
+tests/cases/compiler/a.js(4,12): error TS8010: 'types' can only be used in a .ts file.
+
+
+==== tests/cases/compiler/a.js (2 errors) ====
+    
+    @SomeDecorator
+    class SomeClass {
+          ~~~~~~~~~
+!!! error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
+        foo(x: number) {
+               ~~~~~~
+!!! error TS8010: 'types' can only be used in a .ts file.
+    
+        }
+    }

tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.errors.txt

@@ -5,16 +5,12 @@ tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAs
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(4,6): error TS2459: Type 'string | number | {}' has no property 'i1' and no string index signature.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(5,12): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(5,21): error TS2353: Object literal may only specify known properties, and 'f212' does not exist in type '{ f21: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(6,7): error TS1180: Property destructuring pattern expected.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,5): error TS2353: Object literal may only specify known properties, and 'a' does not exist in type '{ d1: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,11): error TS2353: Object literal may only specify known properties, and 'b' does not exist in type '{ d1: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,24): error TS2353: Object literal may only specify known properties, and 'e' does not exist in type '{ d1: any; }'.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(9,7): error TS1005: ':' expected.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(9,15): error TS1005: ':' expected.
-tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(10,12): error TS1005: ':' expected.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(6,7): error TS1005: ':' expected.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(6,15): error TS1005: ':' expected.
+tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts(7,12): error TS1005: ':' expected.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts (13 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAssignment3.ts (9 errors) ====
     // Error
     var {h?} = { h?: 1 };
           ~
@@ -33,17 +29,6 @@ tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAs
 !!! error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
                         ~~~~
 !!! error TS2353: Object literal may only specify known properties, and 'f212' does not exist in type '{ f21: any; }'.
-    var { ...d1 } = {
-          ~~~
-!!! error TS1180: Property destructuring pattern expected.
-        a: 1, b: 1, d1: 9, e: 10
-        ~
-!!! error TS2353: Object literal may only specify known properties, and 'a' does not exist in type '{ d1: any; }'.
-              ~
-!!! error TS2353: Object literal may only specify known properties, and 'b' does not exist in type '{ d1: any; }'.
-                           ~
-!!! error TS2353: Object literal may only specify known properties, and 'e' does not exist in type '{ d1: any; }'.
-    }
     var {1} = { 1 };
           ~
 !!! error TS1005: ':' expected.
@@ -51,4 +36,5 @@ tests/cases/conformance/es6/destructuring/destructuringObjectBindingPatternAndAs
 !!! error TS1005: ':' expected.
     var {"prop"} = { "prop": 1 };
                ~
-!!! error TS1005: ':' expected.
+!!! error TS1005: ':' expected.
+    

tests/baselines/reference/destructuringObjectBindingPatternAndAssignment3.js

@@ -4,11 +4,9 @@ var {h?} = { h?: 1 };
 var {i}: string | number = { i: 2 };
 var {i1}: string | number| {} = { i1: 2 };
 var { f2: {f21} = { f212: "string" } }: any = undefined;
-var { ...d1 } = {
-    a: 1, b: 1, d1: 9, e: 10
-}
 var {1} = { 1 };
-var {"prop"} = { "prop": 1 };
+var {"prop"} = { "prop": 1 };
+
 
 //// [destructuringObjectBindingPatternAndAssignment3.js]
 // Error
@@ -16,8 +14,5 @@ var h = { h: 1 }.h;
 var i = { i: 2 }.i;
 var i1 = { i1: 2 }.i1;
 var _a = undefined.f2, f21 = (_a === void 0 ? { f212: "string" } : _a).f21;
-var d1 = {
-    a: 1, b: 1, d1: 9, e: 10
-}.d1;
 var  = { 1:  }[1];
 var  = { "prop": 1 }["prop"];

tests/baselines/reference/interfaceSpread.errors.txt

@@ -0,0 +1,21 @@
+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; }>'.
+
+
+==== tests/cases/conformance/types/spread/interfaceSpread.ts (3 errors) ====
+    interface Congealed<T, U> {
+        ...T
+        ~~~~
+!!! error TS2698: Interface declaration cannot contain a spread property.
+        ...U
+    }
+    
+    let sandwich: Congealed<{jam: number }, { peanutButter: number }>;
+    sandwich.jam;
+             ~~~
+!!! error TS2339: Property 'jam' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+    sandwich.peanutButter;
+             ~~~~~~~~~~~~
+!!! error TS2339: Property 'peanutButter' does not exist on type 'Congealed<{ jam: number; }, { peanutButter: number; }>'.
+    

tests/baselines/reference/interfaceSpread.js

@@ -0,0 +1,15 @@
+//// [interfaceSpread.ts]
+interface Congealed<T, U> {
+    ...T
+    ...U
+}
+
+let sandwich: Congealed<{jam: number }, { peanutButter: number }>;
+sandwich.jam;
+sandwich.peanutButter;
+
+
+//// [interfaceSpread.js]
+var sandwich;
+sandwich.jam;
+sandwich.peanutButter;

tests/baselines/reference/jsFileCompilationAbstractModifier.errors.txt

@@ -0,0 +1,16 @@
+error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
+tests/cases/compiler/a.js(1,1): error TS8009: 'abstract' can only be used in a .ts file.
+tests/cases/compiler/a.js(2,5): error TS8009: 'abstract' can only be used in a .ts file.
+
+
+!!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig
+==== tests/cases/compiler/a.js (2 errors) ====
+    abstract class c {
+    ~~~~~~~~
+!!! error TS8009: 'abstract' can only be used in a .ts file.
+        abstract x;
+        ~~~~~~~~
+!!! error TS8009: 'abstract' can only be used in a .ts file.
+    }

tests/baselines/reference/jsFileCompilationConstModifier.symbols

@@ -0,0 +1,4 @@
+=== tests/cases/compiler/a.js ===
+const c = 10;
+>c : Symbol(c, Decl(a.js, 0, 5))
+

tests/baselines/reference/jsFileCompilationConstModifier.types

@@ -0,0 +1,5 @@
+=== tests/cases/compiler/a.js ===
+const c = 10;
+>c : 10
+>10 : 10
+

tests/baselines/reference/jsxFactoryAndReactNamespace.errors.txt

@@ -0,0 +1,53 @@
+error TS5053: Option 'reactNamespace' cannot be specified with option 'jsxFactory'.
+
+
+!!! error TS5053: Option 'reactNamespace' cannot be specified with option 'jsxFactory'.
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (0 errors) ====
+    import { Element} from './Element';
+    
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			<meta content={c.a!.b}></meta>
+    		];
+    	}
+    }

tests/baselines/reference/jsxFactoryAndReactNamespace.js

@@ -0,0 +1,81 @@
+//// [tests/cases/compiler/jsxFactoryAndReactNamespace.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+const Element_1 = require("./Element");
+let c;
+class A {
+    view() {
+        return [
+            Element_1.Element.createElement("meta", { content: "helloworld" }),
+            Element_1.Element.createElement("meta", { content: c.a.b })
+        ];
+    }
+}

tests/baselines/reference/jsxFactoryIdentifier.js

@@ -0,0 +1,83 @@
+//// [tests/cases/compiler/jsxFactoryIdentifier.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+let createElement = Element.createElement;
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//# sourceMappingURL=Element.js.map//// [test.js]
+"use strict";
+const Element_1 = require("./Element");
+let createElement = Element_1.Element.createElement;
+let c;
+class A {
+    view() {
+        return [
+            createElement("meta", { content: "helloworld" }),
+            createElement("meta", { content: c.a.b })
+        ];
+    }
+}
+//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryIdentifier.js.map

@@ -0,0 +1,3 @@
+//// [Element.js.map]
+{"version":3,"file":"Element.js","sourceRoot":"","sources":["Element.ts"],"names":[],"mappings":";AAaA,IAAiB,OAAO,CAUvB;AAVD,WAAiB,OAAO;IACpB,mBAA0B,EAAO;QAC7B,MAAM,CAAC,EAAE,CAAC,wBAAwB,KAAK,SAAS,CAAC;IACrD,CAAC;IAFe,iBAAS,YAExB,CAAA;IAED,uBAA8B,IAAW;QAErC,MAAM,CAAC,EACN,CAAA;IACL,CAAC;IAJe,qBAAa,gBAI5B,CAAA;AACL,CAAC,EAVgB,OAAO,GAAP,eAAO,KAAP,eAAO,QAUvB;AAEU,QAAA,aAAa,GAAG,OAAO,CAAC,aAAa,CAAC;AAEjD,qBAAqB,IAAY;IAC7B,MAAM,CAAC,IAAI,CAAC,CAAC,CAAC,CAAC,WAAW,EAAE,GAAG,IAAI,CAAC,SAAS,CAAC,CAAC,CAAC,CAAC;AACrD,CAAC"}//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAAA,uCAAmC;AACnC,IAAI,aAAa,GAAG,iBAAO,CAAC,aAAa,CAAC;AAC1C,IAAI,CAIH,CAAC;AAEF;IACC,IAAI;QACH,MAAM,CAAC;YACN,wBAAM,OAAO,EAAC,YAAY,GAAQ;YAClC,wBAAM,OAAO,EAAE,CAAC,CAAC,CAAE,CAAC,CAAC,GAAS;SAC9B,CAAC;IACH,CAAC;CACD"}

tests/baselines/reference/jsxFactoryIdentifier.sourcemap.txt

@@ -0,0 +1,520 @@
+===================================================================
+JsFile: Element.js
+mapUrl: Element.js.map
+sourceRoot: 
+sources: Element.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/Element.js
+sourceFile:Element.ts
+-------------------------------------------------------------------
+>>>"use strict";
+>>>var Element;
+1 >
+2 >^^^^
+3 >    ^^^^^^^
+4 >           ^
+5 >            ^^^^^^^^^^->
+1 >
+  >declare namespace JSX {
+  >    interface Element {
+  >        name: string;
+  >        isIntrinsic: boolean;
+  >        isCustomElement: boolean;
+  >        toString(renderId?: number): string;
+  >        bindDOM(renderId?: number): number;
+  >        resetComponent(): void;
+  >        instantiateComponents(renderId?: number): number;
+  >        props: any;
+  >    }
+  >}
+  >
+2 >export namespace 
+3 >    Element
+4 >            {
+  >               export function isElement(el: any): el is JSX.Element {
+  >                   return el.markAsChildOfRootElement !== undefined;
+  >               }
+  >           
+  >               export function createElement(args: any[]) {
+  >           
+  >                   return {
+  >                   }
+  >               }
+  >           }
+1 >Emitted(2, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(2, 5) Source(14, 18) + SourceIndex(0)
+3 >Emitted(2, 12) Source(14, 25) + SourceIndex(0)
+4 >Emitted(2, 13) Source(24, 2) + SourceIndex(0)
+---
+>>>(function (Element) {
+1->
+2 >^^^^^^^^^^^
+3 >           ^^^^^^^
+4 >                  ^^^^^^^^^^^->
+1->
+2 >export namespace 
+3 >           Element
+1->Emitted(3, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(3, 12) Source(14, 18) + SourceIndex(0)
+3 >Emitted(3, 19) Source(14, 25) + SourceIndex(0)
+---
+>>>    function isElement(el) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^
+3 >                       ^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1-> {
+  >    
+2 >    export function isElement(
+3 >                       el: any
+1->Emitted(4, 5) Source(15, 5) + SourceIndex(0)
+2 >Emitted(4, 24) Source(15, 31) + SourceIndex(0)
+3 >Emitted(4, 26) Source(15, 38) + SourceIndex(0)
+---
+>>>        return el.markAsChildOfRootElement !== undefined;
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+6 >                  ^^^^^^^^^^^^^^^^^^^^^^^^
+7 >                                          ^^^^^
+8 >                                               ^^^^^^^^^
+9 >                                                        ^
+1->): el is JSX.Element {
+  >        
+2 >        return
+3 >               
+4 >               el
+5 >                 .
+6 >                  markAsChildOfRootElement
+7 >                                           !== 
+8 >                                               undefined
+9 >                                                        ;
+1->Emitted(5, 9) Source(16, 9) + SourceIndex(0)
+2 >Emitted(5, 15) Source(16, 15) + SourceIndex(0)
+3 >Emitted(5, 16) Source(16, 16) + SourceIndex(0)
+4 >Emitted(5, 18) Source(16, 18) + SourceIndex(0)
+5 >Emitted(5, 19) Source(16, 19) + SourceIndex(0)
+6 >Emitted(5, 43) Source(16, 43) + SourceIndex(0)
+7 >Emitted(5, 48) Source(16, 48) + SourceIndex(0)
+8 >Emitted(5, 57) Source(16, 57) + SourceIndex(0)
+9 >Emitted(5, 58) Source(16, 58) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(6, 5) Source(17, 5) + SourceIndex(0)
+2 >Emitted(6, 6) Source(17, 6) + SourceIndex(0)
+---
+>>>    Element.isElement = isElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^
+3 >                     ^^^^^^^^^^^^
+4 >                                 ^
+5 >                                  ^->
+1->
+2 >    isElement
+3 >                     (el: any): el is JSX.Element {
+  >                             return el.markAsChildOfRootElement !== undefined;
+  >                         }
+4 >                                 
+1->Emitted(7, 5) Source(15, 21) + SourceIndex(0)
+2 >Emitted(7, 22) Source(15, 30) + SourceIndex(0)
+3 >Emitted(7, 34) Source(17, 6) + SourceIndex(0)
+4 >Emitted(7, 35) Source(17, 6) + SourceIndex(0)
+---
+>>>    function createElement(args) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^^^
+3 >                           ^^^^
+1->
+  >
+  >    
+2 >    export function createElement(
+3 >                           args: any[]
+1->Emitted(8, 5) Source(19, 5) + SourceIndex(0)
+2 >Emitted(8, 28) Source(19, 35) + SourceIndex(0)
+3 >Emitted(8, 32) Source(19, 46) + SourceIndex(0)
+---
+>>>        return {};
+1 >^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+1 >) {
+  >
+  >        
+2 >        return
+3 >               
+4 >               {
+  >                       }
+5 >                 
+1 >Emitted(9, 9) Source(21, 9) + SourceIndex(0)
+2 >Emitted(9, 15) Source(21, 15) + SourceIndex(0)
+3 >Emitted(9, 16) Source(21, 16) + SourceIndex(0)
+4 >Emitted(9, 18) Source(22, 10) + SourceIndex(0)
+5 >Emitted(9, 19) Source(22, 10) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(10, 5) Source(23, 5) + SourceIndex(0)
+2 >Emitted(10, 6) Source(23, 6) + SourceIndex(0)
+---
+>>>    Element.createElement = createElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^
+3 >                         ^^^^^^^^^^^^^^^^
+4 >                                         ^
+5 >                                          ^^^^^^^^^^^^^^^->
+1->
+2 >    createElement
+3 >                         (args: any[]) {
+  >                         
+  >                                 return {
+  >                                 }
+  >                             }
+4 >                                         
+1->Emitted(11, 5) Source(19, 21) + SourceIndex(0)
+2 >Emitted(11, 26) Source(19, 34) + SourceIndex(0)
+3 >Emitted(11, 42) Source(23, 6) + SourceIndex(0)
+4 >Emitted(11, 43) Source(23, 6) + SourceIndex(0)
+---
+>>>})(Element = exports.Element || (exports.Element = {}));
+1->
+2 >^
+3 > ^^
+4 >   ^^^^^^^
+5 >          ^^^
+6 >             ^^^^^^^^^^^^^^^
+7 >                            ^^^^^
+8 >                                 ^^^^^^^^^^^^^^^
+9 >                                                ^^^^^^^^
+1->
+  >
+2 >}
+3 > 
+4 >   Element
+5 >          
+6 >             Element
+7 >                            
+8 >                                 Element
+9 >                                                 {
+  >                                                    export function isElement(el: any): el is JSX.Element {
+  >                                                        return el.markAsChildOfRootElement !== undefined;
+  >                                                    }
+  >                                                
+  >                                                    export function createElement(args: any[]) {
+  >                                                
+  >                                                        return {
+  >                                                        }
+  >                                                    }
+  >                                                }
+1->Emitted(12, 1) Source(24, 1) + SourceIndex(0)
+2 >Emitted(12, 2) Source(24, 2) + SourceIndex(0)
+3 >Emitted(12, 4) Source(14, 18) + SourceIndex(0)
+4 >Emitted(12, 11) Source(14, 25) + SourceIndex(0)
+5 >Emitted(12, 14) Source(14, 18) + SourceIndex(0)
+6 >Emitted(12, 29) Source(14, 25) + SourceIndex(0)
+7 >Emitted(12, 34) Source(14, 18) + SourceIndex(0)
+8 >Emitted(12, 49) Source(14, 25) + SourceIndex(0)
+9 >Emitted(12, 57) Source(24, 2) + SourceIndex(0)
+---
+>>>exports.createElement = Element.createElement;
+1 >
+2 >^^^^^^^^
+3 >        ^^^^^^^^^^^^^
+4 >                     ^^^
+5 >                        ^^^^^^^
+6 >                               ^
+7 >                                ^^^^^^^^^^^^^
+8 >                                             ^
+1 >
+  >
+  >export let 
+2 >
+3 >        createElement
+4 >                      = 
+5 >                        Element
+6 >                               .
+7 >                                createElement
+8 >                                             ;
+1 >Emitted(13, 1) Source(26, 12) + SourceIndex(0)
+2 >Emitted(13, 9) Source(26, 12) + SourceIndex(0)
+3 >Emitted(13, 22) Source(26, 25) + SourceIndex(0)
+4 >Emitted(13, 25) Source(26, 28) + SourceIndex(0)
+5 >Emitted(13, 32) Source(26, 35) + SourceIndex(0)
+6 >Emitted(13, 33) Source(26, 36) + SourceIndex(0)
+7 >Emitted(13, 46) Source(26, 49) + SourceIndex(0)
+8 >Emitted(13, 47) Source(26, 50) + SourceIndex(0)
+---
+>>>function toCamelCase(text) {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^
+3 >                     ^^^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+  >
+2 >function toCamelCase(
+3 >                     text: string
+1 >Emitted(14, 1) Source(28, 1) + SourceIndex(0)
+2 >Emitted(14, 22) Source(28, 22) + SourceIndex(0)
+3 >Emitted(14, 26) Source(28, 34) + SourceIndex(0)
+---
+>>>    return text[0].toLowerCase() + text.substring(1);
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^
+5 >               ^
+6 >                ^
+7 >                 ^
+8 >                  ^
+9 >                   ^^^^^^^^^^^
+10>                              ^^
+11>                                ^^^
+12>                                   ^^^^
+13>                                       ^
+14>                                        ^^^^^^^^^
+15>                                                 ^
+16>                                                  ^
+17>                                                   ^
+18>                                                    ^
+1->): string {
+  >    
+2 >    return
+3 >           
+4 >           text
+5 >               [
+6 >                0
+7 >                 ]
+8 >                  .
+9 >                   toLowerCase
+10>                              ()
+11>                                 + 
+12>                                   text
+13>                                       .
+14>                                        substring
+15>                                                 (
+16>                                                  1
+17>                                                   )
+18>                                                    ;
+1->Emitted(15, 5) Source(29, 5) + SourceIndex(0)
+2 >Emitted(15, 11) Source(29, 11) + SourceIndex(0)
+3 >Emitted(15, 12) Source(29, 12) + SourceIndex(0)
+4 >Emitted(15, 16) Source(29, 16) + SourceIndex(0)
+5 >Emitted(15, 17) Source(29, 17) + SourceIndex(0)
+6 >Emitted(15, 18) Source(29, 18) + SourceIndex(0)
+7 >Emitted(15, 19) Source(29, 19) + SourceIndex(0)
+8 >Emitted(15, 20) Source(29, 20) + SourceIndex(0)
+9 >Emitted(15, 31) Source(29, 31) + SourceIndex(0)
+10>Emitted(15, 33) Source(29, 33) + SourceIndex(0)
+11>Emitted(15, 36) Source(29, 36) + SourceIndex(0)
+12>Emitted(15, 40) Source(29, 40) + SourceIndex(0)
+13>Emitted(15, 41) Source(29, 41) + SourceIndex(0)
+14>Emitted(15, 50) Source(29, 50) + SourceIndex(0)
+15>Emitted(15, 51) Source(29, 51) + SourceIndex(0)
+16>Emitted(15, 52) Source(29, 52) + SourceIndex(0)
+17>Emitted(15, 53) Source(29, 53) + SourceIndex(0)
+18>Emitted(15, 54) Source(29, 54) + SourceIndex(0)
+---
+>>>}
+1 >
+2 >^
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+2 >}
+1 >Emitted(16, 1) Source(30, 1) + SourceIndex(0)
+2 >Emitted(16, 2) Source(30, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=Element.js.map===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>const Element_1 = require("./Element");
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                       ^^^^^^^^^^^^^^->
+1 >
+2 >import { Element} from './Element';
+1 >Emitted(2, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(2, 40) Source(1, 36) + SourceIndex(0)
+---
+>>>let createElement = Element_1.Element.createElement;
+1->
+2 >^^^^
+3 >    ^^^^^^^^^^^^^
+4 >                 ^^^
+5 >                    ^^^^^^^^^^^^^^^^^
+6 >                                     ^
+7 >                                      ^^^^^^^^^^^^^
+8 >                                                   ^
+1->
+  >
+2 >let 
+3 >    createElement
+4 >                  = 
+5 >                    Element
+6 >                                     .
+7 >                                      createElement
+8 >                                                   ;
+1->Emitted(3, 1) Source(2, 1) + SourceIndex(0)
+2 >Emitted(3, 5) Source(2, 5) + SourceIndex(0)
+3 >Emitted(3, 18) Source(2, 18) + SourceIndex(0)
+4 >Emitted(3, 21) Source(2, 21) + SourceIndex(0)
+5 >Emitted(3, 38) Source(2, 28) + SourceIndex(0)
+6 >Emitted(3, 39) Source(2, 29) + SourceIndex(0)
+7 >Emitted(3, 52) Source(2, 42) + SourceIndex(0)
+8 >Emitted(3, 53) Source(2, 43) + SourceIndex(0)
+---
+>>>let c;
+1 >
+2 >^^^^
+3 >    ^
+4 >     ^
+5 >      ^^^^->
+1 >
+  >
+2 >let 
+3 >    c: {
+  >    	a?: {
+  >    		b: string
+  >    	}
+  >    }
+4 >     ;
+1 >Emitted(4, 1) Source(3, 1) + SourceIndex(0)
+2 >Emitted(4, 5) Source(3, 5) + SourceIndex(0)
+3 >Emitted(4, 6) Source(7, 2) + SourceIndex(0)
+4 >Emitted(4, 7) Source(7, 3) + SourceIndex(0)
+---
+>>>class A {
+1->
+2 >^^^^^^^^^^^^^->
+1->
+  >
+  >
+1->Emitted(5, 1) Source(9, 1) + SourceIndex(0)
+---
+>>>    view() {
+1->^^^^
+2 >    ^^^^
+3 >        ^^^^^^^^^->
+1->class A {
+  >	
+2 >    view
+1->Emitted(6, 5) Source(10, 2) + SourceIndex(0)
+2 >Emitted(6, 9) Source(10, 6) + SourceIndex(0)
+---
+>>>        return [
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->() {
+  >		
+2 >        return
+3 >               
+1->Emitted(7, 9) Source(11, 3) + SourceIndex(0)
+2 >Emitted(7, 15) Source(11, 9) + SourceIndex(0)
+3 >Emitted(7, 16) Source(11, 10) + SourceIndex(0)
+---
+>>>            createElement("meta", { content: "helloworld" }),
+1->^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                    ^^^^^^^
+4 >                                           ^^
+5 >                                             ^^^^^^^^^^^^
+6 >                                                         ^^^
+1->[
+  >			
+2 >            <meta 
+3 >                                    content
+4 >                                           =
+5 >                                             "helloworld"
+6 >                                                         ></meta>
+1->Emitted(8, 13) Source(12, 4) + SourceIndex(0)
+2 >Emitted(8, 37) Source(12, 10) + SourceIndex(0)
+3 >Emitted(8, 44) Source(12, 17) + SourceIndex(0)
+4 >Emitted(8, 46) Source(12, 18) + SourceIndex(0)
+5 >Emitted(8, 58) Source(12, 30) + SourceIndex(0)
+6 >Emitted(8, 61) Source(12, 38) + SourceIndex(0)
+---
+>>>            createElement("meta", { content: c.a.b })
+1 >^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                    ^^^^^^^
+4 >                                           ^^
+5 >                                             ^
+6 >                                              ^
+7 >                                               ^
+8 >                                                ^
+9 >                                                 ^
+10>                                                  ^^^
+1 >,
+  >			
+2 >            <meta 
+3 >                                    content
+4 >                                           ={
+5 >                                             c
+6 >                                              .
+7 >                                               a!
+8 >                                                .
+9 >                                                 b
+10>                                                  }></meta>
+1 >Emitted(9, 13) Source(13, 4) + SourceIndex(0)
+2 >Emitted(9, 37) Source(13, 10) + SourceIndex(0)
+3 >Emitted(9, 44) Source(13, 17) + SourceIndex(0)
+4 >Emitted(9, 46) Source(13, 19) + SourceIndex(0)
+5 >Emitted(9, 47) Source(13, 20) + SourceIndex(0)
+6 >Emitted(9, 48) Source(13, 21) + SourceIndex(0)
+7 >Emitted(9, 49) Source(13, 23) + SourceIndex(0)
+8 >Emitted(9, 50) Source(13, 24) + SourceIndex(0)
+9 >Emitted(9, 51) Source(13, 25) + SourceIndex(0)
+10>Emitted(9, 54) Source(13, 34) + SourceIndex(0)
+---
+>>>        ];
+1 >^^^^^^^^^
+2 >         ^
+1 >
+  >		]
+2 >         ;
+1 >Emitted(10, 10) Source(14, 4) + SourceIndex(0)
+2 >Emitted(10, 11) Source(14, 5) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >	
+2 >    }
+1 >Emitted(11, 5) Source(15, 2) + SourceIndex(0)
+2 >Emitted(11, 6) Source(15, 3) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(12, 2) Source(16, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryIdentifier.symbols

@@ -0,0 +1,125 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+
+    interface Element {
+>Element : Symbol(Element, Decl(Element.ts, 1, 23))
+
+        name: string;
+>name : Symbol(Element.name, Decl(Element.ts, 2, 23))
+
+        isIntrinsic: boolean;
+>isIntrinsic : Symbol(Element.isIntrinsic, Decl(Element.ts, 3, 21))
+
+        isCustomElement: boolean;
+>isCustomElement : Symbol(Element.isCustomElement, Decl(Element.ts, 4, 29))
+
+        toString(renderId?: number): string;
+>toString : Symbol(Element.toString, Decl(Element.ts, 5, 33))
+>renderId : Symbol(renderId, Decl(Element.ts, 6, 17))
+
+        bindDOM(renderId?: number): number;
+>bindDOM : Symbol(Element.bindDOM, Decl(Element.ts, 6, 44))
+>renderId : Symbol(renderId, Decl(Element.ts, 7, 16))
+
+        resetComponent(): void;
+>resetComponent : Symbol(Element.resetComponent, Decl(Element.ts, 7, 43))
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : Symbol(Element.instantiateComponents, Decl(Element.ts, 8, 31))
+>renderId : Symbol(renderId, Decl(Element.ts, 9, 30))
+
+        props: any;
+>props : Symbol(Element.props, Decl(Element.ts, 9, 57))
+    }
+}
+export namespace Element {
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : Symbol(isElement, Decl(Element.ts, 13, 26))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+>Element : Symbol(JSX.Element, Decl(Element.ts, 1, 23))
+
+        return el.markAsChildOfRootElement !== undefined;
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>undefined : Symbol(undefined)
+    }
+
+    export function createElement(args: any[]) {
+>createElement : Symbol(createElement, Decl(Element.ts, 16, 5))
+>args : Symbol(args, Decl(Element.ts, 18, 34))
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : Symbol(createElement, Decl(Element.ts, 25, 10))
+>Element.createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+>createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+
+function toCamelCase(text: string): string {
+>toCamelCase : Symbol(toCamelCase, Decl(Element.ts, 25, 49))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text.substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : Symbol(Element, Decl(test.tsx, 0, 8))
+
+let createElement = Element.createElement;
+>createElement : Symbol(createElement, Decl(test.tsx, 1, 3))
+>Element.createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+>Element : Symbol(Element, Decl(test.tsx, 0, 8))
+>createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+
+let c: {
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+
+	a?: {
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+
+		b: string
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+	}
+};
+
+class A {
+>A : Symbol(A, Decl(test.tsx, 6, 2))
+
+	view() {
+>view : Symbol(A.view, Decl(test.tsx, 8, 9))
+
+		return [
+			<meta content="helloworld"></meta>,
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>meta : Symbol(unknown)
+
+			<meta content={c.a!.b}></meta>
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>c.a!.b : Symbol(b, Decl(test.tsx, 3, 6))
+>c.a : Symbol(a, Decl(test.tsx, 2, 8))
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+>meta : Symbol(unknown)
+
+		];
+	}
+}

tests/baselines/reference/jsxFactoryIdentifier.types

@@ -0,0 +1,140 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : any
+
+    interface Element {
+>Element : Element
+
+        name: string;
+>name : string
+
+        isIntrinsic: boolean;
+>isIntrinsic : boolean
+
+        isCustomElement: boolean;
+>isCustomElement : boolean
+
+        toString(renderId?: number): string;
+>toString : (renderId?: number) => string
+>renderId : number
+
+        bindDOM(renderId?: number): number;
+>bindDOM : (renderId?: number) => number
+>renderId : number
+
+        resetComponent(): void;
+>resetComponent : () => void
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : (renderId?: number) => number
+>renderId : number
+
+        props: any;
+>props : any
+    }
+}
+export namespace Element {
+>Element : typeof Element
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : (el: any) => el is JSX.Element
+>el : any
+>el : any
+>JSX : any
+>Element : JSX.Element
+
+        return el.markAsChildOfRootElement !== undefined;
+>el.markAsChildOfRootElement !== undefined : boolean
+>el.markAsChildOfRootElement : any
+>el : any
+>markAsChildOfRootElement : any
+>undefined : undefined
+    }
+
+    export function createElement(args: any[]) {
+>createElement : (args: any[]) => {}
+>args : any[]
+
+        return {
+>{        } : {}
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : (args: any[]) => {}
+>Element.createElement : (args: any[]) => {}
+>Element : typeof Element
+>createElement : (args: any[]) => {}
+
+function toCamelCase(text: string): string {
+>toCamelCase : (text: string) => string
+>text : string
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase() + text.substring(1) : string
+>text[0].toLowerCase() : string
+>text[0].toLowerCase : () => string
+>text[0] : string
+>text : string
+>0 : 0
+>toLowerCase : () => string
+>text.substring(1) : string
+>text.substring : (start: number, end?: number) => string
+>text : string
+>substring : (start: number, end?: number) => string
+>1 : 1
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : typeof Element
+
+let createElement = Element.createElement;
+>createElement : (args: any[]) => {}
+>Element.createElement : (args: any[]) => {}
+>Element : typeof Element
+>createElement : (args: any[]) => {}
+
+let c: {
+>c : { a?: { b: string; }; }
+
+	a?: {
+>a : { b: string; }
+
+		b: string
+>b : string
+	}
+};
+
+class A {
+>A : A
+
+	view() {
+>view : () => any[]
+
+		return [
+>[			<meta content="helloworld"></meta>,			<meta content={c.a!.b}></meta>		] : any[]
+
+			<meta content="helloworld"></meta>,
+><meta content="helloworld"></meta> : any
+>meta : any
+>content : any
+>meta : any
+
+			<meta content={c.a!.b}></meta>
+><meta content={c.a!.b}></meta> : any
+>meta : any
+>content : any
+>c.a!.b : string
+>c.a! : { b: string; }
+>c.a : { b: string; }
+>c : { a?: { b: string; }; }
+>a : { b: string; }
+>b : string
+>meta : any
+
+		];
+	}
+}

tests/baselines/reference/jsxFactoryIdentifierAsParameter.js

@@ -0,0 +1,24 @@
+//// [test.tsx]
+
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render(createElement) {
+        return <div />;
+    }
+}
+
+
+//// [test.js]
+"use strict";
+class AppComponent {
+    render(createElement) {
+        return createElement("div", null);
+    }
+}
+exports.AppComponent = AppComponent;
+//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryIdentifierAsParameter.js.map

@@ -0,0 +1,2 @@
+//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAOA;IACI,MAAM,CAAC,aAAa;QAChB,MAAM,CAAC,0BAAO,CAAC;IACnB,CAAC;CACJ;AAJD,oCAIC"}

tests/baselines/reference/jsxFactoryIdentifierAsParameter.sourcemap.txt

@@ -0,0 +1,87 @@
+===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>class AppComponent {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >declare module JSX {
+  >    interface IntrinsicElements {
+  >        [s: string]: any;
+  >    }
+  >}
+  >
+  >
+1 >Emitted(2, 1) Source(8, 1) + SourceIndex(0)
+---
+>>>    render(createElement) {
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^^^^^^^^^^
+5 >                        ^^^^^^^^^^^^^^^^^^^->
+1->export class AppComponent {
+  >    
+2 >    render
+3 >          (
+4 >           createElement
+1->Emitted(3, 5) Source(9, 5) + SourceIndex(0)
+2 >Emitted(3, 11) Source(9, 11) + SourceIndex(0)
+3 >Emitted(3, 12) Source(9, 12) + SourceIndex(0)
+4 >Emitted(3, 25) Source(9, 25) + SourceIndex(0)
+---
+>>>        return createElement("div", null);
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^
+5 >                                         ^
+1->) {
+  >        
+2 >        return
+3 >               
+4 >               <div />
+5 >                                         ;
+1->Emitted(4, 9) Source(10, 9) + SourceIndex(0)
+2 >Emitted(4, 15) Source(10, 15) + SourceIndex(0)
+3 >Emitted(4, 16) Source(10, 16) + SourceIndex(0)
+4 >Emitted(4, 42) Source(10, 23) + SourceIndex(0)
+5 >Emitted(4, 43) Source(10, 24) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >    
+2 >    }
+1 >Emitted(5, 5) Source(11, 5) + SourceIndex(0)
+2 >Emitted(5, 6) Source(11, 6) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(6, 2) Source(12, 2) + SourceIndex(0)
+---
+>>>exports.AppComponent = AppComponent;
+1->
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1->
+2 >export class AppComponent {
+  >    render(createElement) {
+  >        return <div />;
+  >    }
+  >}
+1->Emitted(7, 1) Source(8, 1) + SourceIndex(0)
+2 >Emitted(7, 37) Source(12, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryIdentifierAsParameter.symbols

@@ -0,0 +1,25 @@
+=== tests/cases/compiler/test.tsx ===
+
+declare module JSX {
+>JSX : Symbol(JSX, Decl(test.tsx, 0, 0))
+
+    interface IntrinsicElements {
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(test.tsx, 1, 20))
+
+        [s: string]: any;
+>s : Symbol(s, Decl(test.tsx, 3, 9))
+    }
+}
+
+export class AppComponent {
+>AppComponent : Symbol(AppComponent, Decl(test.tsx, 5, 1))
+
+    render(createElement) {
+>render : Symbol(AppComponent.render, Decl(test.tsx, 7, 27))
+>createElement : Symbol(createElement, Decl(test.tsx, 8, 11))
+
+        return <div />;
+>div : Symbol(unknown)
+    }
+}
+

tests/baselines/reference/jsxFactoryIdentifierAsParameter.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/test.tsx ===
+
+declare module JSX {
+>JSX : any
+
+    interface IntrinsicElements {
+>IntrinsicElements : IntrinsicElements
+
+        [s: string]: any;
+>s : string
+    }
+}
+
+export class AppComponent {
+>AppComponent : AppComponent
+
+    render(createElement) {
+>render : (createElement: any) => any
+>createElement : any
+
+        return <div />;
+><div /> : any
+>div : any
+    }
+}
+

tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.errors.txt

@@ -0,0 +1,19 @@
+tests/cases/compiler/test.tsx(10,17): error TS2304: Cannot find name 'createElement'.
+
+
+==== tests/cases/compiler/test.tsx (1 errors) ====
+    
+    declare module JSX {
+        interface IntrinsicElements {
+            [s: string]: any;
+        }
+    }
+    
+    export class AppComponent {
+        render() {
+            return <div />;
+                    ~~~
+!!! error TS2304: Cannot find name 'createElement'.
+        }
+    }
+    

tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js

@@ -0,0 +1,24 @@
+//// [test.tsx]
+
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render() {
+        return <div />;
+    }
+}
+
+
+//// [test.js]
+"use strict";
+class AppComponent {
+    render() {
+        return createElement("div", null);
+    }
+}
+exports.AppComponent = AppComponent;
+//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.js.map

@@ -0,0 +1,2 @@
+//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAOA;IACI,MAAM;QACF,MAAM,CAAC,0BAAO,CAAC;IACnB,CAAC;CACJ;AAJD,oCAIC"}

tests/baselines/reference/jsxFactoryIdentifierWithAbsentParameter.sourcemap.txt

@@ -0,0 +1,81 @@
+===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>class AppComponent {
+1 >
+2 >^^^^^^^^^^^^^^^->
+1 >
+  >declare module JSX {
+  >    interface IntrinsicElements {
+  >        [s: string]: any;
+  >    }
+  >}
+  >
+  >
+1 >Emitted(2, 1) Source(8, 1) + SourceIndex(0)
+---
+>>>    render() {
+1->^^^^
+2 >    ^^^^^^
+3 >          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->export class AppComponent {
+  >    
+2 >    render
+1->Emitted(3, 5) Source(9, 5) + SourceIndex(0)
+2 >Emitted(3, 11) Source(9, 11) + SourceIndex(0)
+---
+>>>        return createElement("div", null);
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^
+5 >                                         ^
+1->() {
+  >        
+2 >        return
+3 >               
+4 >               <div />
+5 >                                         ;
+1->Emitted(4, 9) Source(10, 9) + SourceIndex(0)
+2 >Emitted(4, 15) Source(10, 15) + SourceIndex(0)
+3 >Emitted(4, 16) Source(10, 16) + SourceIndex(0)
+4 >Emitted(4, 42) Source(10, 23) + SourceIndex(0)
+5 >Emitted(4, 43) Source(10, 24) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >    
+2 >    }
+1 >Emitted(5, 5) Source(11, 5) + SourceIndex(0)
+2 >Emitted(5, 6) Source(11, 6) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(6, 2) Source(12, 2) + SourceIndex(0)
+---
+>>>exports.AppComponent = AppComponent;
+1->
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1->
+2 >export class AppComponent {
+  >    render() {
+  >        return <div />;
+  >    }
+  >}
+1->Emitted(7, 1) Source(8, 1) + SourceIndex(0)
+2 >Emitted(7, 37) Source(12, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.errors.txt

@@ -0,0 +1,59 @@
+error TS5067: Invalid value for 'jsxFactory'. 'Element.createElement=' is not a valid identifier or qualified-name.
+tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
+tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
+
+
+!!! error TS5067: Invalid value for 'jsxFactory'. 'Element.createElement=' is not a valid identifier or qualified-name.
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (2 errors) ====
+    import { Element} from './Element';
+    
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    			<meta content={c.a!.b}></meta>
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    		];
+    	}
+    }

tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName.js

@@ -0,0 +1,80 @@
+//// [tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+let c;
+class A {
+    view() {
+        return [
+            React.createElement("meta", { content: "helloworld" }),
+            React.createElement("meta", { content: c.a.b })
+        ];
+    }
+}

tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.errors.txt

@@ -0,0 +1,59 @@
+error TS5067: Invalid value for 'jsxFactory'. 'id1 id2' is not a valid identifier or qualified-name.
+tests/cases/compiler/test.tsx(12,5): error TS2304: Cannot find name 'React'.
+tests/cases/compiler/test.tsx(13,5): error TS2304: Cannot find name 'React'.
+
+
+!!! error TS5067: Invalid value for 'jsxFactory'. 'id1 id2' is not a valid identifier or qualified-name.
+==== tests/cases/compiler/Element.ts (0 errors) ====
+    
+    declare namespace JSX {
+        interface Element {
+            name: string;
+            isIntrinsic: boolean;
+            isCustomElement: boolean;
+            toString(renderId?: number): string;
+            bindDOM(renderId?: number): number;
+            resetComponent(): void;
+            instantiateComponents(renderId?: number): number;
+            props: any;
+        }
+    }
+    export namespace Element {
+        export function isElement(el: any): el is JSX.Element {
+            return el.markAsChildOfRootElement !== undefined;
+        }
+    
+        export function createElement(args: any[]) {
+    
+            return {
+            }
+        }
+    }
+    
+    export let createElement = Element.createElement;
+    
+    function toCamelCase(text: string): string {
+        return text[0].toLowerCase() + text.substring(1);
+    }
+    
+==== tests/cases/compiler/test.tsx (2 errors) ====
+    import { Element} from './Element';
+    
+    let c: {
+    	a?: {
+    		b: string
+    	}
+    };
+    
+    class A {
+    	view() {
+    		return [
+    			<meta content="helloworld"></meta>,
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    			<meta content={c.a!.b}></meta>
+    			 ~~~~
+!!! error TS2304: Cannot find name 'React'.
+    		];
+    	}
+    }

tests/baselines/reference/jsxFactoryNotIdentifierOrQualifiedName2.js

@@ -0,0 +1,80 @@
+//// [tests/cases/compiler/jsxFactoryNotIdentifierOrQualifiedName2.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//// [test.js]
+"use strict";
+let c;
+class A {
+    view() {
+        return [
+            React.createElement("meta", { content: "helloworld" }),
+            React.createElement("meta", { content: c.a.b })
+        ];
+    }
+}

tests/baselines/reference/jsxFactoryQualifiedName.js

@@ -0,0 +1,82 @@
+//// [tests/cases/compiler/jsxFactoryQualifiedName.ts] ////
+
+//// [Element.ts]
+
+declare namespace JSX {
+    interface Element {
+        name: string;
+        isIntrinsic: boolean;
+        isCustomElement: boolean;
+        toString(renderId?: number): string;
+        bindDOM(renderId?: number): number;
+        resetComponent(): void;
+        instantiateComponents(renderId?: number): number;
+        props: any;
+    }
+}
+export namespace Element {
+    export function isElement(el: any): el is JSX.Element {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+
+    export function createElement(args: any[]) {
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+
+function toCamelCase(text: string): string {
+    return text[0].toLowerCase() + text.substring(1);
+}
+
+//// [test.tsx]
+import { Element} from './Element';
+
+let c: {
+	a?: {
+		b: string
+	}
+};
+
+class A {
+	view() {
+		return [
+			<meta content="helloworld"></meta>,
+			<meta content={c.a!.b}></meta>
+		];
+	}
+}
+
+//// [Element.js]
+"use strict";
+var Element;
+(function (Element) {
+    function isElement(el) {
+        return el.markAsChildOfRootElement !== undefined;
+    }
+    Element.isElement = isElement;
+    function createElement(args) {
+        return {};
+    }
+    Element.createElement = createElement;
+})(Element = exports.Element || (exports.Element = {}));
+exports.createElement = Element.createElement;
+function toCamelCase(text) {
+    return text[0].toLowerCase() + text.substring(1);
+}
+//# sourceMappingURL=Element.js.map//// [test.js]
+"use strict";
+const Element_1 = require("./Element");
+let c;
+class A {
+    view() {
+        return [
+            Element_1.Element.createElement("meta", { content: "helloworld" }),
+            Element_1.Element.createElement("meta", { content: c.a.b })
+        ];
+    }
+}
+//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryQualifiedName.js.map

@@ -0,0 +1,3 @@
+//// [Element.js.map]
+{"version":3,"file":"Element.js","sourceRoot":"","sources":["Element.ts"],"names":[],"mappings":";AAaA,IAAiB,OAAO,CAUvB;AAVD,WAAiB,OAAO;IACpB,mBAA0B,EAAO;QAC7B,MAAM,CAAC,EAAE,CAAC,wBAAwB,KAAK,SAAS,CAAC;IACrD,CAAC;IAFe,iBAAS,YAExB,CAAA;IAED,uBAA8B,IAAW;QAErC,MAAM,CAAC,EACN,CAAA;IACL,CAAC;IAJe,qBAAa,gBAI5B,CAAA;AACL,CAAC,EAVgB,OAAO,GAAP,eAAO,KAAP,eAAO,QAUvB;AAEU,QAAA,aAAa,GAAG,OAAO,CAAC,aAAa,CAAC;AAEjD,qBAAqB,IAAY;IAC7B,MAAM,CAAC,IAAI,CAAC,CAAC,CAAC,CAAC,WAAW,EAAE,GAAG,IAAI,CAAC,SAAS,CAAC,CAAC,CAAC,CAAC;AACrD,CAAC"}//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAAA,uCAAmC;AAEnC,IAAI,CAIH,CAAC;AAEF;IACC,IAAI;QACH,MAAM,CAAC;YACN,0CAAM,OAAO,EAAC,YAAY,GAAQ;YAClC,0CAAM,OAAO,EAAE,CAAC,CAAC,CAAE,CAAC,CAAC,GAAS;SAC9B,CAAC;IACH,CAAC;CACD"}

tests/baselines/reference/jsxFactoryQualifiedName.sourcemap.txt

@@ -0,0 +1,493 @@
+===================================================================
+JsFile: Element.js
+mapUrl: Element.js.map
+sourceRoot: 
+sources: Element.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/Element.js
+sourceFile:Element.ts
+-------------------------------------------------------------------
+>>>"use strict";
+>>>var Element;
+1 >
+2 >^^^^
+3 >    ^^^^^^^
+4 >           ^
+5 >            ^^^^^^^^^^->
+1 >
+  >declare namespace JSX {
+  >    interface Element {
+  >        name: string;
+  >        isIntrinsic: boolean;
+  >        isCustomElement: boolean;
+  >        toString(renderId?: number): string;
+  >        bindDOM(renderId?: number): number;
+  >        resetComponent(): void;
+  >        instantiateComponents(renderId?: number): number;
+  >        props: any;
+  >    }
+  >}
+  >
+2 >export namespace 
+3 >    Element
+4 >            {
+  >               export function isElement(el: any): el is JSX.Element {
+  >                   return el.markAsChildOfRootElement !== undefined;
+  >               }
+  >           
+  >               export function createElement(args: any[]) {
+  >           
+  >                   return {
+  >                   }
+  >               }
+  >           }
+1 >Emitted(2, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(2, 5) Source(14, 18) + SourceIndex(0)
+3 >Emitted(2, 12) Source(14, 25) + SourceIndex(0)
+4 >Emitted(2, 13) Source(24, 2) + SourceIndex(0)
+---
+>>>(function (Element) {
+1->
+2 >^^^^^^^^^^^
+3 >           ^^^^^^^
+4 >                  ^^^^^^^^^^^->
+1->
+2 >export namespace 
+3 >           Element
+1->Emitted(3, 1) Source(14, 1) + SourceIndex(0)
+2 >Emitted(3, 12) Source(14, 18) + SourceIndex(0)
+3 >Emitted(3, 19) Source(14, 25) + SourceIndex(0)
+---
+>>>    function isElement(el) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^
+3 >                       ^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1-> {
+  >    
+2 >    export function isElement(
+3 >                       el: any
+1->Emitted(4, 5) Source(15, 5) + SourceIndex(0)
+2 >Emitted(4, 24) Source(15, 31) + SourceIndex(0)
+3 >Emitted(4, 26) Source(15, 38) + SourceIndex(0)
+---
+>>>        return el.markAsChildOfRootElement !== undefined;
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+6 >                  ^^^^^^^^^^^^^^^^^^^^^^^^
+7 >                                          ^^^^^
+8 >                                               ^^^^^^^^^
+9 >                                                        ^
+1->): el is JSX.Element {
+  >        
+2 >        return
+3 >               
+4 >               el
+5 >                 .
+6 >                  markAsChildOfRootElement
+7 >                                           !== 
+8 >                                               undefined
+9 >                                                        ;
+1->Emitted(5, 9) Source(16, 9) + SourceIndex(0)
+2 >Emitted(5, 15) Source(16, 15) + SourceIndex(0)
+3 >Emitted(5, 16) Source(16, 16) + SourceIndex(0)
+4 >Emitted(5, 18) Source(16, 18) + SourceIndex(0)
+5 >Emitted(5, 19) Source(16, 19) + SourceIndex(0)
+6 >Emitted(5, 43) Source(16, 43) + SourceIndex(0)
+7 >Emitted(5, 48) Source(16, 48) + SourceIndex(0)
+8 >Emitted(5, 57) Source(16, 57) + SourceIndex(0)
+9 >Emitted(5, 58) Source(16, 58) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(6, 5) Source(17, 5) + SourceIndex(0)
+2 >Emitted(6, 6) Source(17, 6) + SourceIndex(0)
+---
+>>>    Element.isElement = isElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^
+3 >                     ^^^^^^^^^^^^
+4 >                                 ^
+5 >                                  ^->
+1->
+2 >    isElement
+3 >                     (el: any): el is JSX.Element {
+  >                             return el.markAsChildOfRootElement !== undefined;
+  >                         }
+4 >                                 
+1->Emitted(7, 5) Source(15, 21) + SourceIndex(0)
+2 >Emitted(7, 22) Source(15, 30) + SourceIndex(0)
+3 >Emitted(7, 34) Source(17, 6) + SourceIndex(0)
+4 >Emitted(7, 35) Source(17, 6) + SourceIndex(0)
+---
+>>>    function createElement(args) {
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^^^
+3 >                           ^^^^
+1->
+  >
+  >    
+2 >    export function createElement(
+3 >                           args: any[]
+1->Emitted(8, 5) Source(19, 5) + SourceIndex(0)
+2 >Emitted(8, 28) Source(19, 35) + SourceIndex(0)
+3 >Emitted(8, 32) Source(19, 46) + SourceIndex(0)
+---
+>>>        return {};
+1 >^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^
+5 >                 ^
+1 >) {
+  >
+  >        
+2 >        return
+3 >               
+4 >               {
+  >                       }
+5 >                 
+1 >Emitted(9, 9) Source(21, 9) + SourceIndex(0)
+2 >Emitted(9, 15) Source(21, 15) + SourceIndex(0)
+3 >Emitted(9, 16) Source(21, 16) + SourceIndex(0)
+4 >Emitted(9, 18) Source(22, 10) + SourceIndex(0)
+5 >Emitted(9, 19) Source(22, 10) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >    
+2 >    }
+1 >Emitted(10, 5) Source(23, 5) + SourceIndex(0)
+2 >Emitted(10, 6) Source(23, 6) + SourceIndex(0)
+---
+>>>    Element.createElement = createElement;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^
+3 >                         ^^^^^^^^^^^^^^^^
+4 >                                         ^
+5 >                                          ^^^^^^^^^^^^^^^->
+1->
+2 >    createElement
+3 >                         (args: any[]) {
+  >                         
+  >                                 return {
+  >                                 }
+  >                             }
+4 >                                         
+1->Emitted(11, 5) Source(19, 21) + SourceIndex(0)
+2 >Emitted(11, 26) Source(19, 34) + SourceIndex(0)
+3 >Emitted(11, 42) Source(23, 6) + SourceIndex(0)
+4 >Emitted(11, 43) Source(23, 6) + SourceIndex(0)
+---
+>>>})(Element = exports.Element || (exports.Element = {}));
+1->
+2 >^
+3 > ^^
+4 >   ^^^^^^^
+5 >          ^^^
+6 >             ^^^^^^^^^^^^^^^
+7 >                            ^^^^^
+8 >                                 ^^^^^^^^^^^^^^^
+9 >                                                ^^^^^^^^
+1->
+  >
+2 >}
+3 > 
+4 >   Element
+5 >          
+6 >             Element
+7 >                            
+8 >                                 Element
+9 >                                                 {
+  >                                                    export function isElement(el: any): el is JSX.Element {
+  >                                                        return el.markAsChildOfRootElement !== undefined;
+  >                                                    }
+  >                                                
+  >                                                    export function createElement(args: any[]) {
+  >                                                
+  >                                                        return {
+  >                                                        }
+  >                                                    }
+  >                                                }
+1->Emitted(12, 1) Source(24, 1) + SourceIndex(0)
+2 >Emitted(12, 2) Source(24, 2) + SourceIndex(0)
+3 >Emitted(12, 4) Source(14, 18) + SourceIndex(0)
+4 >Emitted(12, 11) Source(14, 25) + SourceIndex(0)
+5 >Emitted(12, 14) Source(14, 18) + SourceIndex(0)
+6 >Emitted(12, 29) Source(14, 25) + SourceIndex(0)
+7 >Emitted(12, 34) Source(14, 18) + SourceIndex(0)
+8 >Emitted(12, 49) Source(14, 25) + SourceIndex(0)
+9 >Emitted(12, 57) Source(24, 2) + SourceIndex(0)
+---
+>>>exports.createElement = Element.createElement;
+1 >
+2 >^^^^^^^^
+3 >        ^^^^^^^^^^^^^
+4 >                     ^^^
+5 >                        ^^^^^^^
+6 >                               ^
+7 >                                ^^^^^^^^^^^^^
+8 >                                             ^
+1 >
+  >
+  >export let 
+2 >
+3 >        createElement
+4 >                      = 
+5 >                        Element
+6 >                               .
+7 >                                createElement
+8 >                                             ;
+1 >Emitted(13, 1) Source(26, 12) + SourceIndex(0)
+2 >Emitted(13, 9) Source(26, 12) + SourceIndex(0)
+3 >Emitted(13, 22) Source(26, 25) + SourceIndex(0)
+4 >Emitted(13, 25) Source(26, 28) + SourceIndex(0)
+5 >Emitted(13, 32) Source(26, 35) + SourceIndex(0)
+6 >Emitted(13, 33) Source(26, 36) + SourceIndex(0)
+7 >Emitted(13, 46) Source(26, 49) + SourceIndex(0)
+8 >Emitted(13, 47) Source(26, 50) + SourceIndex(0)
+---
+>>>function toCamelCase(text) {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^
+3 >                     ^^^^
+4 >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+  >
+2 >function toCamelCase(
+3 >                     text: string
+1 >Emitted(14, 1) Source(28, 1) + SourceIndex(0)
+2 >Emitted(14, 22) Source(28, 22) + SourceIndex(0)
+3 >Emitted(14, 26) Source(28, 34) + SourceIndex(0)
+---
+>>>    return text[0].toLowerCase() + text.substring(1);
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^
+5 >               ^
+6 >                ^
+7 >                 ^
+8 >                  ^
+9 >                   ^^^^^^^^^^^
+10>                              ^^
+11>                                ^^^
+12>                                   ^^^^
+13>                                       ^
+14>                                        ^^^^^^^^^
+15>                                                 ^
+16>                                                  ^
+17>                                                   ^
+18>                                                    ^
+1->): string {
+  >    
+2 >    return
+3 >           
+4 >           text
+5 >               [
+6 >                0
+7 >                 ]
+8 >                  .
+9 >                   toLowerCase
+10>                              ()
+11>                                 + 
+12>                                   text
+13>                                       .
+14>                                        substring
+15>                                                 (
+16>                                                  1
+17>                                                   )
+18>                                                    ;
+1->Emitted(15, 5) Source(29, 5) + SourceIndex(0)
+2 >Emitted(15, 11) Source(29, 11) + SourceIndex(0)
+3 >Emitted(15, 12) Source(29, 12) + SourceIndex(0)
+4 >Emitted(15, 16) Source(29, 16) + SourceIndex(0)
+5 >Emitted(15, 17) Source(29, 17) + SourceIndex(0)
+6 >Emitted(15, 18) Source(29, 18) + SourceIndex(0)
+7 >Emitted(15, 19) Source(29, 19) + SourceIndex(0)
+8 >Emitted(15, 20) Source(29, 20) + SourceIndex(0)
+9 >Emitted(15, 31) Source(29, 31) + SourceIndex(0)
+10>Emitted(15, 33) Source(29, 33) + SourceIndex(0)
+11>Emitted(15, 36) Source(29, 36) + SourceIndex(0)
+12>Emitted(15, 40) Source(29, 40) + SourceIndex(0)
+13>Emitted(15, 41) Source(29, 41) + SourceIndex(0)
+14>Emitted(15, 50) Source(29, 50) + SourceIndex(0)
+15>Emitted(15, 51) Source(29, 51) + SourceIndex(0)
+16>Emitted(15, 52) Source(29, 52) + SourceIndex(0)
+17>Emitted(15, 53) Source(29, 53) + SourceIndex(0)
+18>Emitted(15, 54) Source(29, 54) + SourceIndex(0)
+---
+>>>}
+1 >
+2 >^
+3 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >
+2 >}
+1 >Emitted(16, 1) Source(30, 1) + SourceIndex(0)
+2 >Emitted(16, 2) Source(30, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=Element.js.map===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>const Element_1 = require("./Element");
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1 >
+2 >import { Element} from './Element';
+1 >Emitted(2, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(2, 40) Source(1, 36) + SourceIndex(0)
+---
+>>>let c;
+1 >
+2 >^^^^
+3 >    ^
+4 >     ^
+5 >      ^^^^->
+1 >
+  >
+  >
+2 >let 
+3 >    c: {
+  >    	a?: {
+  >    		b: string
+  >    	}
+  >    }
+4 >     ;
+1 >Emitted(3, 1) Source(3, 1) + SourceIndex(0)
+2 >Emitted(3, 5) Source(3, 5) + SourceIndex(0)
+3 >Emitted(3, 6) Source(7, 2) + SourceIndex(0)
+4 >Emitted(3, 7) Source(7, 3) + SourceIndex(0)
+---
+>>>class A {
+1->
+2 >^^^^^^^^^^^^^->
+1->
+  >
+  >
+1->Emitted(4, 1) Source(9, 1) + SourceIndex(0)
+---
+>>>    view() {
+1->^^^^
+2 >    ^^^^
+3 >        ^^^^^^^^^->
+1->class A {
+  >	
+2 >    view
+1->Emitted(5, 5) Source(10, 2) + SourceIndex(0)
+2 >Emitted(5, 9) Source(10, 6) + SourceIndex(0)
+---
+>>>        return [
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->() {
+  >		
+2 >        return
+3 >               
+1->Emitted(6, 9) Source(11, 3) + SourceIndex(0)
+2 >Emitted(6, 15) Source(11, 9) + SourceIndex(0)
+3 >Emitted(6, 16) Source(11, 10) + SourceIndex(0)
+---
+>>>            Element_1.Element.createElement("meta", { content: "helloworld" }),
+1->^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                                      ^^^^^^^
+4 >                                                             ^^
+5 >                                                               ^^^^^^^^^^^^
+6 >                                                                           ^^^
+1->[
+  >			
+2 >            <meta 
+3 >                                                      content
+4 >                                                             =
+5 >                                                               "helloworld"
+6 >                                                                           ></meta>
+1->Emitted(7, 13) Source(12, 4) + SourceIndex(0)
+2 >Emitted(7, 55) Source(12, 10) + SourceIndex(0)
+3 >Emitted(7, 62) Source(12, 17) + SourceIndex(0)
+4 >Emitted(7, 64) Source(12, 18) + SourceIndex(0)
+5 >Emitted(7, 76) Source(12, 30) + SourceIndex(0)
+6 >Emitted(7, 79) Source(12, 38) + SourceIndex(0)
+---
+>>>            Element_1.Element.createElement("meta", { content: c.a.b })
+1 >^^^^^^^^^^^^
+2 >            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                                      ^^^^^^^
+4 >                                                             ^^
+5 >                                                               ^
+6 >                                                                ^
+7 >                                                                 ^
+8 >                                                                  ^
+9 >                                                                   ^
+10>                                                                    ^^^
+1 >,
+  >			
+2 >            <meta 
+3 >                                                      content
+4 >                                                             ={
+5 >                                                               c
+6 >                                                                .
+7 >                                                                 a!
+8 >                                                                  .
+9 >                                                                   b
+10>                                                                    }></meta>
+1 >Emitted(8, 13) Source(13, 4) + SourceIndex(0)
+2 >Emitted(8, 55) Source(13, 10) + SourceIndex(0)
+3 >Emitted(8, 62) Source(13, 17) + SourceIndex(0)
+4 >Emitted(8, 64) Source(13, 19) + SourceIndex(0)
+5 >Emitted(8, 65) Source(13, 20) + SourceIndex(0)
+6 >Emitted(8, 66) Source(13, 21) + SourceIndex(0)
+7 >Emitted(8, 67) Source(13, 23) + SourceIndex(0)
+8 >Emitted(8, 68) Source(13, 24) + SourceIndex(0)
+9 >Emitted(8, 69) Source(13, 25) + SourceIndex(0)
+10>Emitted(8, 72) Source(13, 34) + SourceIndex(0)
+---
+>>>        ];
+1 >^^^^^^^^^
+2 >         ^
+1 >
+  >		]
+2 >         ;
+1 >Emitted(9, 10) Source(14, 4) + SourceIndex(0)
+2 >Emitted(9, 11) Source(14, 5) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >	
+2 >    }
+1 >Emitted(10, 5) Source(15, 2) + SourceIndex(0)
+2 >Emitted(10, 6) Source(15, 3) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(11, 2) Source(16, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryQualifiedName.symbols

@@ -0,0 +1,119 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+
+    interface Element {
+>Element : Symbol(Element, Decl(Element.ts, 1, 23))
+
+        name: string;
+>name : Symbol(Element.name, Decl(Element.ts, 2, 23))
+
+        isIntrinsic: boolean;
+>isIntrinsic : Symbol(Element.isIntrinsic, Decl(Element.ts, 3, 21))
+
+        isCustomElement: boolean;
+>isCustomElement : Symbol(Element.isCustomElement, Decl(Element.ts, 4, 29))
+
+        toString(renderId?: number): string;
+>toString : Symbol(Element.toString, Decl(Element.ts, 5, 33))
+>renderId : Symbol(renderId, Decl(Element.ts, 6, 17))
+
+        bindDOM(renderId?: number): number;
+>bindDOM : Symbol(Element.bindDOM, Decl(Element.ts, 6, 44))
+>renderId : Symbol(renderId, Decl(Element.ts, 7, 16))
+
+        resetComponent(): void;
+>resetComponent : Symbol(Element.resetComponent, Decl(Element.ts, 7, 43))
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : Symbol(Element.instantiateComponents, Decl(Element.ts, 8, 31))
+>renderId : Symbol(renderId, Decl(Element.ts, 9, 30))
+
+        props: any;
+>props : Symbol(Element.props, Decl(Element.ts, 9, 57))
+    }
+}
+export namespace Element {
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : Symbol(isElement, Decl(Element.ts, 13, 26))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>JSX : Symbol(JSX, Decl(Element.ts, 0, 0))
+>Element : Symbol(JSX.Element, Decl(Element.ts, 1, 23))
+
+        return el.markAsChildOfRootElement !== undefined;
+>el : Symbol(el, Decl(Element.ts, 14, 30))
+>undefined : Symbol(undefined)
+    }
+
+    export function createElement(args: any[]) {
+>createElement : Symbol(createElement, Decl(Element.ts, 16, 5))
+>args : Symbol(args, Decl(Element.ts, 18, 34))
+
+        return {
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : Symbol(createElement, Decl(Element.ts, 25, 10))
+>Element.createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+>Element : Symbol(Element, Decl(Element.ts, 12, 1))
+>createElement : Symbol(Element.createElement, Decl(Element.ts, 16, 5))
+
+function toCamelCase(text: string): string {
+>toCamelCase : Symbol(toCamelCase, Decl(Element.ts, 25, 49))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
+>text.substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+>text : Symbol(text, Decl(Element.ts, 27, 21))
+>substring : Symbol(String.substring, Decl(lib.es5.d.ts, --, --))
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : Symbol(Element, Decl(test.tsx, 0, 8))
+
+let c: {
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+
+	a?: {
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+
+		b: string
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+	}
+};
+
+class A {
+>A : Symbol(A, Decl(test.tsx, 6, 2))
+
+	view() {
+>view : Symbol(A.view, Decl(test.tsx, 8, 9))
+
+		return [
+			<meta content="helloworld"></meta>,
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>meta : Symbol(unknown)
+
+			<meta content={c.a!.b}></meta>
+>meta : Symbol(unknown)
+>content : Symbol(unknown)
+>c.a!.b : Symbol(b, Decl(test.tsx, 3, 6))
+>c.a : Symbol(a, Decl(test.tsx, 2, 8))
+>c : Symbol(c, Decl(test.tsx, 2, 3))
+>a : Symbol(a, Decl(test.tsx, 2, 8))
+>b : Symbol(b, Decl(test.tsx, 3, 6))
+>meta : Symbol(unknown)
+
+		];
+	}
+}

tests/baselines/reference/jsxFactoryQualifiedName.types

@@ -0,0 +1,134 @@
+=== tests/cases/compiler/Element.ts ===
+
+declare namespace JSX {
+>JSX : any
+
+    interface Element {
+>Element : Element
+
+        name: string;
+>name : string
+
+        isIntrinsic: boolean;
+>isIntrinsic : boolean
+
+        isCustomElement: boolean;
+>isCustomElement : boolean
+
+        toString(renderId?: number): string;
+>toString : (renderId?: number) => string
+>renderId : number
+
+        bindDOM(renderId?: number): number;
+>bindDOM : (renderId?: number) => number
+>renderId : number
+
+        resetComponent(): void;
+>resetComponent : () => void
+
+        instantiateComponents(renderId?: number): number;
+>instantiateComponents : (renderId?: number) => number
+>renderId : number
+
+        props: any;
+>props : any
+    }
+}
+export namespace Element {
+>Element : typeof Element
+
+    export function isElement(el: any): el is JSX.Element {
+>isElement : (el: any) => el is JSX.Element
+>el : any
+>el : any
+>JSX : any
+>Element : JSX.Element
+
+        return el.markAsChildOfRootElement !== undefined;
+>el.markAsChildOfRootElement !== undefined : boolean
+>el.markAsChildOfRootElement : any
+>el : any
+>markAsChildOfRootElement : any
+>undefined : undefined
+    }
+
+    export function createElement(args: any[]) {
+>createElement : (args: any[]) => {}
+>args : any[]
+
+        return {
+>{        } : {}
+        }
+    }
+}
+
+export let createElement = Element.createElement;
+>createElement : (args: any[]) => {}
+>Element.createElement : (args: any[]) => {}
+>Element : typeof Element
+>createElement : (args: any[]) => {}
+
+function toCamelCase(text: string): string {
+>toCamelCase : (text: string) => string
+>text : string
+
+    return text[0].toLowerCase() + text.substring(1);
+>text[0].toLowerCase() + text.substring(1) : string
+>text[0].toLowerCase() : string
+>text[0].toLowerCase : () => string
+>text[0] : string
+>text : string
+>0 : 0
+>toLowerCase : () => string
+>text.substring(1) : string
+>text.substring : (start: number, end?: number) => string
+>text : string
+>substring : (start: number, end?: number) => string
+>1 : 1
+}
+
+=== tests/cases/compiler/test.tsx ===
+import { Element} from './Element';
+>Element : typeof Element
+
+let c: {
+>c : { a?: { b: string; }; }
+
+	a?: {
+>a : { b: string; }
+
+		b: string
+>b : string
+	}
+};
+
+class A {
+>A : A
+
+	view() {
+>view : () => any[]
+
+		return [
+>[			<meta content="helloworld"></meta>,			<meta content={c.a!.b}></meta>		] : any[]
+
+			<meta content="helloworld"></meta>,
+><meta content="helloworld"></meta> : any
+>meta : any
+>content : any
+>meta : any
+
+			<meta content={c.a!.b}></meta>
+><meta content={c.a!.b}></meta> : any
+>meta : any
+>content : any
+>c.a!.b : string
+>c.a! : { b: string; }
+>c.a : { b: string; }
+>c : { a?: { b: string; }; }
+>a : { b: string; }
+>b : string
+>meta : any
+
+		];
+	}
+}

tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.errors.txt

@@ -0,0 +1,18 @@
+tests/cases/compiler/test.tsx(10,17): error TS2304: Cannot find name 'MyElement'.
+
+
+==== tests/cases/compiler/test.tsx (1 errors) ====
+    
+    declare module JSX {
+        interface IntrinsicElements {
+            [s: string]: any;
+        }
+    }
+    
+    export class AppComponent {
+        render(createElement) {
+            return <div />;
+                    ~~~
+!!! error TS2304: Cannot find name 'MyElement'.
+        }
+    }

tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js

@@ -0,0 +1,23 @@
+//// [test.tsx]
+
+declare module JSX {
+    interface IntrinsicElements {
+        [s: string]: any;
+    }
+}
+
+export class AppComponent {
+    render(createElement) {
+        return <div />;
+    }
+}
+
+//// [test.js]
+"use strict";
+class AppComponent {
+    render(createElement) {
+        return MyElement.createElement("div", null);
+    }
+}
+exports.AppComponent = AppComponent;
+//# sourceMappingURL=test.js.map

tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.js.map

@@ -0,0 +1,2 @@
+//// [test.js.map]
+{"version":3,"file":"test.js","sourceRoot":"","sources":["test.tsx"],"names":[],"mappings":";AAOA;IACI,MAAM,CAAC,aAAa;QAChB,MAAM,CAAC,oCAAO,CAAC;IACnB,CAAC;CACJ;AAJD,oCAIC"}

tests/baselines/reference/jsxFactoryQualifiedNameResolutionError.sourcemap.txt

@@ -0,0 +1,87 @@
+===================================================================
+JsFile: test.js
+mapUrl: test.js.map
+sourceRoot: 
+sources: test.tsx
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/compiler/test.js
+sourceFile:test.tsx
+-------------------------------------------------------------------
+>>>"use strict";
+>>>class AppComponent {
+1 >
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >declare module JSX {
+  >    interface IntrinsicElements {
+  >        [s: string]: any;
+  >    }
+  >}
+  >
+  >
+1 >Emitted(2, 1) Source(8, 1) + SourceIndex(0)
+---
+>>>    render(createElement) {
+1->^^^^
+2 >    ^^^^^^
+3 >          ^
+4 >           ^^^^^^^^^^^^^
+5 >                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->export class AppComponent {
+  >    
+2 >    render
+3 >          (
+4 >           createElement
+1->Emitted(3, 5) Source(9, 5) + SourceIndex(0)
+2 >Emitted(3, 11) Source(9, 11) + SourceIndex(0)
+3 >Emitted(3, 12) Source(9, 12) + SourceIndex(0)
+4 >Emitted(3, 25) Source(9, 25) + SourceIndex(0)
+---
+>>>        return MyElement.createElement("div", null);
+1->^^^^^^^^
+2 >        ^^^^^^
+3 >              ^
+4 >               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+5 >                                                   ^
+1->) {
+  >        
+2 >        return
+3 >               
+4 >               <div />
+5 >                                                   ;
+1->Emitted(4, 9) Source(10, 9) + SourceIndex(0)
+2 >Emitted(4, 15) Source(10, 15) + SourceIndex(0)
+3 >Emitted(4, 16) Source(10, 16) + SourceIndex(0)
+4 >Emitted(4, 52) Source(10, 23) + SourceIndex(0)
+5 >Emitted(4, 53) Source(10, 24) + SourceIndex(0)
+---
+>>>    }
+1 >^^^^
+2 >    ^
+1 >
+  >    
+2 >    }
+1 >Emitted(5, 5) Source(11, 5) + SourceIndex(0)
+2 >Emitted(5, 6) Source(11, 6) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(6, 2) Source(12, 2) + SourceIndex(0)
+---
+>>>exports.AppComponent = AppComponent;
+1->
+2 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+1->
+2 >export class AppComponent {
+  >    render(createElement) {
+  >        return <div />;
+  >    }
+  >}
+1->Emitted(7, 1) Source(8, 1) + SourceIndex(0)
+2 >Emitted(7, 37) Source(12, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=test.js.map

tests/baselines/reference/objectRest.js

@@ -0,0 +1,67 @@
+//// [objectRest.ts]
+let o = { a: 1, b: 'no' }
+var { ...clone } = o;
+var { a, ...justB } = o;
+var { a, b: renamed, ...empty } = o;
+var { ['b']: renamed, ...justA } = o;
+var { 'b': renamed, ...justA } = o;
+var { b: { '0': n, '1': oooo }, ...justA } = o;
+
+let o2 = { c: 'terrible idea?', d: 'yes' };
+var { d: renamed, ...d } = o2;
+
+let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+
+let complex: { x: { ka, ki }, y: number };
+var { x: { ka, ...nested }, y: other, ...rest } = complex;
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+var { x, ...fresh } = { x: 1, y: 2 };
+({ x, ...fresh } = { x: 1, y: 2 });
+
+class Removable {
+    private x: number;
+    protected y: number;
+    set z(value: number) { }
+    get both(): number { return 12 }
+    set both(value: number) { }
+    m() { }
+    removed: string;
+    remainder: string;
+}
+var removable = new Removable();
+var { removed, ...removableRest } = removable;
+
+
+//// [objectRest.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+let o = { a: 1, b: 'no' };
+var clone = __rest(o, []);
+var { a } = o, justB = __rest(o, ["a"]);
+var { a, b: renamed } = o, empty = __rest(o, ["a", "b"]);
+var { ['b']: renamed } = o, justA = __rest(o, ["b"]);
+var { 'b': renamed } = o, justA = __rest(o, ["b"]);
+var { b: { '0': n, '1': oooo } } = o, justA = __rest(o, ["b"]);
+let o2 = { c: 'terrible idea?', d: 'yes' };
+var { d: renamed } = o2, d = __rest(o2, ["d"]);
+let nestedrest;
+var { x } = nestedrest, _a = nestedrest.n1, { y } = _a, _b = _a.n2, { z } = _b, nr = __rest(_b.n3, []), restrest = __rest(nestedrest, ["x", "n1"]);
+let complex;
+var _c = complex.x, { ka } = _c, nested = __rest(_c, ["ka"]), { y: other } = complex, rest = __rest(complex, ["x", "y"]);
+(_d = complex.x, { ka } = _d, nested = __rest(_d, ["ka"]), { y: other } = complex, rest = __rest(complex, ["x", "y"]), complex);
+var _e = { x: 1, y: 2 }, { x } = _e, fresh = __rest(_e, ["x"]);
+(_f = { x: 1, y: 2 }, { x } = _f, fresh = __rest(_f, ["x"]), _f);
+class Removable {
+    set z(value) { }
+    get both() { return 12; }
+    set both(value) { }
+    m() { }
+}
+var removable = new Removable();
+var { removed } = removable, removableRest = __rest(removable, ["removed"]);
+var _d, _f;

tests/baselines/reference/objectRest.symbols

@@ -0,0 +1,146 @@
+=== tests/cases/conformance/types/rest/objectRest.ts ===
+let o = { a: 1, b: 'no' }
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+>a : Symbol(a, Decl(objectRest.ts, 0, 9))
+>b : Symbol(b, Decl(objectRest.ts, 0, 15))
+
+var { ...clone } = o;
+>clone : Symbol(clone, Decl(objectRest.ts, 1, 5))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { a, ...justB } = o;
+>a : Symbol(a, Decl(objectRest.ts, 2, 5), Decl(objectRest.ts, 3, 5))
+>justB : Symbol(justB, Decl(objectRest.ts, 2, 8))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { a, b: renamed, ...empty } = o;
+>a : Symbol(a, Decl(objectRest.ts, 2, 5), Decl(objectRest.ts, 3, 5))
+>b : Symbol(b, Decl(objectRest.ts, 0, 15))
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>empty : Symbol(empty, Decl(objectRest.ts, 3, 20))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { ['b']: renamed, ...justA } = o;
+>'b' : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>justA : Symbol(justA, Decl(objectRest.ts, 4, 21), Decl(objectRest.ts, 5, 19), Decl(objectRest.ts, 6, 31))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { 'b': renamed, ...justA } = o;
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>justA : Symbol(justA, Decl(objectRest.ts, 4, 21), Decl(objectRest.ts, 5, 19), Decl(objectRest.ts, 6, 31))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+var { b: { '0': n, '1': oooo }, ...justA } = o;
+>b : Symbol(b, Decl(objectRest.ts, 0, 15))
+>n : Symbol(n, Decl(objectRest.ts, 6, 10))
+>oooo : Symbol(oooo, Decl(objectRest.ts, 6, 18))
+>justA : Symbol(justA, Decl(objectRest.ts, 4, 21), Decl(objectRest.ts, 5, 19), Decl(objectRest.ts, 6, 31))
+>o : Symbol(o, Decl(objectRest.ts, 0, 3))
+
+let o2 = { c: 'terrible idea?', d: 'yes' };
+>o2 : Symbol(o2, Decl(objectRest.ts, 8, 3))
+>c : Symbol(c, Decl(objectRest.ts, 8, 10))
+>d : Symbol(d, Decl(objectRest.ts, 8, 31))
+
+var { d: renamed, ...d } = o2;
+>d : Symbol(d, Decl(objectRest.ts, 8, 31))
+>renamed : Symbol(renamed, Decl(objectRest.ts, 3, 8), Decl(objectRest.ts, 4, 5), Decl(objectRest.ts, 5, 5), Decl(objectRest.ts, 9, 5))
+>d : Symbol(d, Decl(objectRest.ts, 9, 17))
+>o2 : Symbol(o2, Decl(objectRest.ts, 8, 3))
+
+let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+>nestedrest : Symbol(nestedrest, Decl(objectRest.ts, 11, 3))
+>x : Symbol(x, Decl(objectRest.ts, 11, 17))
+>n1 : Symbol(n1, Decl(objectRest.ts, 11, 28))
+>y : Symbol(y, Decl(objectRest.ts, 11, 34))
+>n2 : Symbol(n2, Decl(objectRest.ts, 11, 45))
+>z : Symbol(z, Decl(objectRest.ts, 11, 51))
+>n3 : Symbol(n3, Decl(objectRest.ts, 11, 62))
+>n4 : Symbol(n4, Decl(objectRest.ts, 11, 68))
+>rest : Symbol(rest, Decl(objectRest.ts, 11, 86))
+>restrest : Symbol(restrest, Decl(objectRest.ts, 11, 100))
+
+var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+>x : Symbol(x, Decl(objectRest.ts, 12, 5), Decl(objectRest.ts, 17, 5))
+>n1 : Symbol(n1, Decl(objectRest.ts, 11, 28))
+>y : Symbol(y, Decl(objectRest.ts, 12, 14))
+>n2 : Symbol(n2, Decl(objectRest.ts, 11, 45))
+>z : Symbol(z, Decl(objectRest.ts, 12, 23))
+>n3 : Symbol(n3, Decl(objectRest.ts, 11, 62))
+>nr : Symbol(nr, Decl(objectRest.ts, 12, 32))
+>restrest : Symbol(restrest, Decl(objectRest.ts, 12, 45))
+>nestedrest : Symbol(nestedrest, Decl(objectRest.ts, 11, 3))
+
+let complex: { x: { ka, ki }, y: number };
+>complex : Symbol(complex, Decl(objectRest.ts, 14, 3))
+>x : Symbol(x, Decl(objectRest.ts, 14, 14))
+>ka : Symbol(ka, Decl(objectRest.ts, 14, 19))
+>ki : Symbol(ki, Decl(objectRest.ts, 14, 23))
+>y : Symbol(y, Decl(objectRest.ts, 14, 29))
+
+var { x: { ka, ...nested }, y: other, ...rest } = complex;
+>x : Symbol(x, Decl(objectRest.ts, 14, 14))
+>ka : Symbol(ka, Decl(objectRest.ts, 15, 10))
+>nested : Symbol(nested, Decl(objectRest.ts, 15, 14))
+>y : Symbol(y, Decl(objectRest.ts, 14, 29))
+>other : Symbol(other, Decl(objectRest.ts, 15, 27))
+>rest : Symbol(rest, Decl(objectRest.ts, 15, 37))
+>complex : Symbol(complex, Decl(objectRest.ts, 14, 3))
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>x : Symbol(x, Decl(objectRest.ts, 16, 2))
+>ka : Symbol(ka, Decl(objectRest.ts, 16, 6))
+>y : Symbol(y, Decl(objectRest.ts, 16, 23))
+>other : Symbol(other, Decl(objectRest.ts, 15, 27))
+>complex : Symbol(complex, Decl(objectRest.ts, 14, 3))
+
+var { x, ...fresh } = { x: 1, y: 2 };
+>x : Symbol(x, Decl(objectRest.ts, 12, 5), Decl(objectRest.ts, 17, 5))
+>fresh : Symbol(fresh, Decl(objectRest.ts, 17, 8))
+>x : Symbol(x, Decl(objectRest.ts, 17, 23))
+>y : Symbol(y, Decl(objectRest.ts, 17, 29))
+
+({ x, ...fresh } = { x: 1, y: 2 });
+>x : Symbol(x, Decl(objectRest.ts, 18, 2))
+>x : Symbol(x, Decl(objectRest.ts, 18, 20))
+>y : Symbol(y, Decl(objectRest.ts, 18, 26))
+
+class Removable {
+>Removable : Symbol(Removable, Decl(objectRest.ts, 18, 35))
+
+    private x: number;
+>x : Symbol(Removable.x, Decl(objectRest.ts, 20, 17))
+
+    protected y: number;
+>y : Symbol(Removable.y, Decl(objectRest.ts, 21, 22))
+
+    set z(value: number) { }
+>z : Symbol(Removable.z, Decl(objectRest.ts, 22, 24))
+>value : Symbol(value, Decl(objectRest.ts, 23, 10))
+
+    get both(): number { return 12 }
+>both : Symbol(Removable.both, Decl(objectRest.ts, 23, 28), Decl(objectRest.ts, 24, 36))
+
+    set both(value: number) { }
+>both : Symbol(Removable.both, Decl(objectRest.ts, 23, 28), Decl(objectRest.ts, 24, 36))
+>value : Symbol(value, Decl(objectRest.ts, 25, 13))
+
+    m() { }
+>m : Symbol(Removable.m, Decl(objectRest.ts, 25, 31))
+
+    removed: string;
+>removed : Symbol(Removable.removed, Decl(objectRest.ts, 26, 11))
+
+    remainder: string;
+>remainder : Symbol(Removable.remainder, Decl(objectRest.ts, 27, 20))
+}
+var removable = new Removable();
+>removable : Symbol(removable, Decl(objectRest.ts, 30, 3))
+>Removable : Symbol(Removable, Decl(objectRest.ts, 18, 35))
+
+var { removed, ...removableRest } = removable;
+>removed : Symbol(removed, Decl(objectRest.ts, 31, 5))
+>removableRest : Symbol(removableRest, Decl(objectRest.ts, 31, 14))
+>removable : Symbol(removable, Decl(objectRest.ts, 30, 3))
+

tests/baselines/reference/objectRest.types

@@ -0,0 +1,170 @@
+=== tests/cases/conformance/types/rest/objectRest.ts ===
+let o = { a: 1, b: 'no' }
+>o : { a: number; b: string; }
+>{ a: 1, b: 'no' } : { a: number; b: string; }
+>a : number
+>1 : 1
+>b : string
+>'no' : "no"
+
+var { ...clone } = o;
+>clone : { a: number; b: string; }
+>o : { a: number; b: string; }
+
+var { a, ...justB } = o;
+>a : number
+>justB : { b: string; }
+>o : { a: number; b: string; }
+
+var { a, b: renamed, ...empty } = o;
+>a : number
+>b : any
+>renamed : string
+>empty : {}
+>o : { a: number; b: string; }
+
+var { ['b']: renamed, ...justA } = o;
+>'b' : "b"
+>renamed : string
+>justA : { a: number; }
+>o : { a: number; b: string; }
+
+var { 'b': renamed, ...justA } = o;
+>renamed : string
+>justA : { a: number; }
+>o : { a: number; b: string; }
+
+var { b: { '0': n, '1': oooo }, ...justA } = o;
+>b : any
+>n : string
+>oooo : string
+>justA : { a: number; }
+>o : { a: number; b: string; }
+
+let o2 = { c: 'terrible idea?', d: 'yes' };
+>o2 : { c: string; d: string; }
+>{ c: 'terrible idea?', d: 'yes' } : { c: string; d: string; }
+>c : string
+>'terrible idea?' : "terrible idea?"
+>d : string
+>'yes' : "yes"
+
+var { d: renamed, ...d } = o2;
+>d : any
+>renamed : string
+>d : { c: string; }
+>o2 : { c: string; d: string; }
+
+let nestedrest: { x: number, n1: { y: number, n2: { z: number, n3: { n4: number } } }, rest: number, restrest: number };
+>nestedrest : { x: number; n1: { y: number; n2: { z: number; n3: { n4: number; }; }; }; rest: number; restrest: number; }
+>x : number
+>n1 : { y: number; n2: { z: number; n3: { n4: number; }; }; }
+>y : number
+>n2 : { z: number; n3: { n4: number; }; }
+>z : number
+>n3 : { n4: number; }
+>n4 : number
+>rest : number
+>restrest : number
+
+var { x, n1: { y, n2: { z, n3: { ...nr } } }, ...restrest } = nestedrest;
+>x : number
+>n1 : any
+>y : number
+>n2 : any
+>z : number
+>n3 : any
+>nr : { n4: number; }
+>restrest : { rest: number; restrest: number; }
+>nestedrest : { x: number; n1: { y: number; n2: { z: number; n3: { n4: number; }; }; }; rest: number; restrest: number; }
+
+let complex: { x: { ka, ki }, y: number };
+>complex : { x: { ka: any; ki: any; }; y: number; }
+>x : { ka: any; ki: any; }
+>ka : any
+>ki : any
+>y : number
+
+var { x: { ka, ...nested }, y: other, ...rest } = complex;
+>x : any
+>ka : any
+>nested : { ki: any; }
+>y : any
+>other : number
+>rest : {}
+>complex : { x: { ka: any; ki: any; }; y: number; }
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>({x: { ka, ...nested }, y: other, ...rest} = complex) : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} = complex : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} : { x: { ki: any; ka: any; }; y: number; }
+>x : { ki: any; ka: any; }
+>{ ka, ...nested } : { ki: any; ka: any; }
+>ka : any
+>nested : any
+>y : number
+>other : number
+>rest : any
+>complex : { x: { ka: any; ki: any; }; y: number; }
+
+var { x, ...fresh } = { x: 1, y: 2 };
+>x : number
+>fresh : { y: number; }
+>{ x: 1, y: 2 } : { x: number; y: number; }
+>x : number
+>1 : 1
+>y : number
+>2 : 2
+
+({ x, ...fresh } = { x: 1, y: 2 });
+>({ x, ...fresh } = { x: 1, y: 2 }) : { x: number; y: number; }
+>{ x, ...fresh } = { x: 1, y: 2 } : { x: number; y: number; }
+>{ x, ...fresh } : { y: number; x: number; }
+>x : number
+>fresh : any
+>{ x: 1, y: 2 } : { x: number; y: number; }
+>x : number
+>1 : 1
+>y : number
+>2 : 2
+
+class Removable {
+>Removable : Removable
+
+    private x: number;
+>x : number
+
+    protected y: number;
+>y : number
+
+    set z(value: number) { }
+>z : number
+>value : number
+
+    get both(): number { return 12 }
+>both : number
+>12 : 12
+
+    set both(value: number) { }
+>both : number
+>value : number
+
+    m() { }
+>m : () => void
+
+    removed: string;
+>removed : string
+
+    remainder: string;
+>remainder : string
+}
+var removable = new Removable();
+>removable : Removable
+>new Removable() : Removable
+>Removable : typeof Removable
+
+var { removed, ...removableRest } = removable;
+>removed : string
+>removableRest : { both: number; remainder: string; }
+>removable : Removable
+

tests/baselines/reference/objectRestAssignment.js

@@ -0,0 +1,35 @@
+//// [objectRestAssignment.ts]
+let ka: any;
+let nested: { ki };
+let other: number;
+let rest: { };
+let complex: { x: { ka, ki }, y: number };
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+
+// should be:
+let overEmit: { a: { ka: string, x: string }[], b: { z: string, ki: string, ku: string }, ke: string, ko: string };
+
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
+({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);
+
+
+//// [objectRestAssignment.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+let ka;
+let nested;
+let other;
+let rest;
+let complex;
+(_a = complex.x, { ka } = _a, nested = __rest(_a, ["ka"]), { y: other } = complex, rest = __rest(complex, ["x", "y"]), complex);
+// should be:
+let overEmit;
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var _b = overEmit.a, [_c, ...y] = _b, nested2 = __rest(_c, []), _d = overEmit.b, { z } = _d, c = __rest(_d, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+(_e = overEmit.a, [_f, ...y] = _e, nested2 = __rest(_f, []), _g = overEmit.b, { z } = _g, c = __rest(_g, ["z"]), rest2 = __rest(overEmit, ["a", "b"]), overEmit);
+var _a, _e, _f, _g;

tests/baselines/reference/objectRestAssignment.symbols

@@ -0,0 +1,59 @@
+=== tests/cases/conformance/types/rest/objectRestAssignment.ts ===
+let ka: any;
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 0, 3))
+
+let nested: { ki };
+>nested : Symbol(nested, Decl(objectRestAssignment.ts, 1, 3))
+>ki : Symbol(ki, Decl(objectRestAssignment.ts, 1, 13))
+
+let other: number;
+>other : Symbol(other, Decl(objectRestAssignment.ts, 2, 3))
+
+let rest: { };
+>rest : Symbol(rest, Decl(objectRestAssignment.ts, 3, 3))
+
+let complex: { x: { ka, ki }, y: number };
+>complex : Symbol(complex, Decl(objectRestAssignment.ts, 4, 3))
+>x : Symbol(x, Decl(objectRestAssignment.ts, 4, 14))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 4, 19))
+>ki : Symbol(ki, Decl(objectRestAssignment.ts, 4, 23))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 4, 29))
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>x : Symbol(x, Decl(objectRestAssignment.ts, 5, 2))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 5, 6))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 5, 23))
+>other : Symbol(other, Decl(objectRestAssignment.ts, 2, 3))
+>complex : Symbol(complex, Decl(objectRestAssignment.ts, 4, 3))
+
+// should be:
+let overEmit: { a: { ka: string, x: string }[], b: { z: string, ki: string, ku: string }, ke: string, ko: string };
+>overEmit : Symbol(overEmit, Decl(objectRestAssignment.ts, 8, 3))
+>a : Symbol(a, Decl(objectRestAssignment.ts, 8, 15))
+>ka : Symbol(ka, Decl(objectRestAssignment.ts, 8, 20))
+>x : Symbol(x, Decl(objectRestAssignment.ts, 8, 32))
+>b : Symbol(b, Decl(objectRestAssignment.ts, 8, 47))
+>z : Symbol(z, Decl(objectRestAssignment.ts, 8, 52))
+>ki : Symbol(ki, Decl(objectRestAssignment.ts, 8, 63))
+>ku : Symbol(ku, Decl(objectRestAssignment.ts, 8, 75))
+>ke : Symbol(ke, Decl(objectRestAssignment.ts, 8, 89))
+>ko : Symbol(ko, Decl(objectRestAssignment.ts, 8, 101))
+
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
+>a : Symbol(a, Decl(objectRestAssignment.ts, 8, 15))
+>nested2 : Symbol(nested2, Decl(objectRestAssignment.ts, 11, 11))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 11, 25))
+>b : Symbol(b, Decl(objectRestAssignment.ts, 8, 47))
+>z : Symbol(z, Decl(objectRestAssignment.ts, 11, 37))
+>c : Symbol(c, Decl(objectRestAssignment.ts, 11, 40))
+>rest2 : Symbol(rest2, Decl(objectRestAssignment.ts, 11, 48))
+>overEmit : Symbol(overEmit, Decl(objectRestAssignment.ts, 8, 3))
+
+({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);
+>a : Symbol(a, Decl(objectRestAssignment.ts, 12, 2))
+>y : Symbol(y, Decl(objectRestAssignment.ts, 11, 25))
+>b : Symbol(b, Decl(objectRestAssignment.ts, 12, 29))
+>z : Symbol(z, Decl(objectRestAssignment.ts, 12, 34))
+>overEmit : Symbol(overEmit, Decl(objectRestAssignment.ts, 8, 3))
+

tests/baselines/reference/objectRestAssignment.types

@@ -0,0 +1,75 @@
+=== tests/cases/conformance/types/rest/objectRestAssignment.ts ===
+let ka: any;
+>ka : any
+
+let nested: { ki };
+>nested : { ki: any; }
+>ki : any
+
+let other: number;
+>other : number
+
+let rest: { };
+>rest : {}
+
+let complex: { x: { ka, ki }, y: number };
+>complex : { x: { ka: any; ki: any; }; y: number; }
+>x : { ka: any; ki: any; }
+>ka : any
+>ki : any
+>y : number
+
+({x: { ka, ...nested }, y: other, ...rest} = complex);
+>({x: { ka, ...nested }, y: other, ...rest} = complex) : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} = complex : { x: { ka: any; ki: any; }; y: number; }
+>{x: { ka, ...nested }, y: other, ...rest} : { x: { ki: any; ka: any; }; y: number; }
+>x : { ki: any; ka: any; }
+>{ ka, ...nested } : { ki: any; ka: any; }
+>ka : any
+>nested : any
+>y : number
+>other : number
+>rest : any
+>complex : { x: { ka: any; ki: any; }; y: number; }
+
+// should be:
+let overEmit: { a: { ka: string, x: string }[], b: { z: string, ki: string, ku: string }, ke: string, ko: string };
+>overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+>a : { ka: string; x: string; }[]
+>ka : string
+>x : string
+>b : { z: string; ki: string; ku: string; }
+>z : string
+>ki : string
+>ku : string
+>ke : string
+>ko : string
+
+// var _g = overEmit.a, [_h, ...y] = _g, nested2 = __rest(_h, []), _j = overEmit.b, { z } = _j, c = __rest(_j, ["z"]), rest2 = __rest(overEmit, ["a", "b"]);
+var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
+>a : any
+>nested2 : { ka: string; x: string; }
+>y : { ka: string; x: string; }[]
+>b : any
+>z : string
+>c : { ki: string; ku: string; }
+>rest2 : { ke: string; ko: string; }
+>overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+
+({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);
+>({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit) : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+>{ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+>{ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } : { ke: string; ko: string; a: { ka: string; x: string; }[]; b: { ki: string; ku: string; z: string; }; }
+>a : { ka: string; x: string; }[]
+>[{ ...nested2 }, ...y] : { ka: string; x: string; }[]
+>{ ...nested2 } : { ka: string; x: string; }
+>nested2 : any
+>...y : { ka: string; x: string; }
+>y : { ka: string; x: string; }[]
+>b : { ki: string; ku: string; z: string; }
+>{ z, ...c } : { ki: string; ku: string; z: string; }
+>z : string
+>c : any
+>rest2 : any
+>overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
+

tests/baselines/reference/objectRestForOf.js

@@ -0,0 +1,45 @@
+//// [objectRestForOf.ts]
+let array: { x: number, y: string }[];
+for (let { x, ...restOf } of array) {
+    [x, restOf];
+}
+let xx: number;
+let rrestOff: { y: string };
+for ({ x: xx, ...rrestOff } of array ) {
+    [xx, rrestOff];
+}
+for (const norest of array.map(a => ({ ...a, x: 'a string' }))) {
+    [norest.x, norest.y];
+    // x is now a string. who knows why.
+}
+
+
+//// [objectRestForOf.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+let array;
+for (var array_1 of array) {
+    var { x } = array_1, restOf = __rest(array_1, ["x"]);
+    [x, restOf];
+}
+let xx;
+let rrestOff;
+for (var array_2 of array) {
+    ({ x: xx } = array_2, rrestOff = __rest(array_2, ["x"]));
+    [xx, rrestOff];
+}
+for (const norest of array.map(a => (__assign({}, a, { x: 'a string' })))) {
+    [norest.x, norest.y];
+}

tests/baselines/reference/objectRestForOf.symbols

@@ -0,0 +1,50 @@
+=== tests/cases/conformance/types/rest/objectRestForOf.ts ===
+let array: { x: number, y: string }[];
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+>x : Symbol(x, Decl(objectRestForOf.ts, 0, 12))
+>y : Symbol(y, Decl(objectRestForOf.ts, 0, 23))
+
+for (let { x, ...restOf } of array) {
+>x : Symbol(x, Decl(objectRestForOf.ts, 1, 10))
+>restOf : Symbol(restOf, Decl(objectRestForOf.ts, 1, 13))
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+
+    [x, restOf];
+>x : Symbol(x, Decl(objectRestForOf.ts, 1, 10))
+>restOf : Symbol(restOf, Decl(objectRestForOf.ts, 1, 13))
+}
+let xx: number;
+>xx : Symbol(xx, Decl(objectRestForOf.ts, 4, 3))
+
+let rrestOff: { y: string };
+>rrestOff : Symbol(rrestOff, Decl(objectRestForOf.ts, 5, 3))
+>y : Symbol(y, Decl(objectRestForOf.ts, 5, 15))
+
+for ({ x: xx, ...rrestOff } of array ) {
+>x : Symbol(x, Decl(objectRestForOf.ts, 6, 6))
+>xx : Symbol(xx, Decl(objectRestForOf.ts, 4, 3))
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+
+    [xx, rrestOff];
+>xx : Symbol(xx, Decl(objectRestForOf.ts, 4, 3))
+>rrestOff : Symbol(rrestOff, Decl(objectRestForOf.ts, 5, 3))
+}
+for (const norest of array.map(a => ({ ...a, x: 'a string' }))) {
+>norest : Symbol(norest, Decl(objectRestForOf.ts, 9, 10))
+>array.map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>array : Symbol(array, Decl(objectRestForOf.ts, 0, 3))
+>map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>a : Symbol(a, Decl(objectRestForOf.ts, 9, 31))
+>x : Symbol(x, Decl(objectRestForOf.ts, 9, 44))
+
+    [norest.x, norest.y];
+>norest.x : Symbol(x, Decl(objectRestForOf.ts, 9, 44))
+>norest : Symbol(norest, Decl(objectRestForOf.ts, 9, 10))
+>x : Symbol(x, Decl(objectRestForOf.ts, 9, 44))
+>norest.y : Symbol(y, Decl(objectRestForOf.ts, 0, 23))
+>norest : Symbol(norest, Decl(objectRestForOf.ts, 9, 10))
+>y : Symbol(y, Decl(objectRestForOf.ts, 0, 23))
+
+    // x is now a string. who knows why.
+}
+

tests/baselines/reference/objectRestForOf.types

@@ -0,0 +1,61 @@
+=== tests/cases/conformance/types/rest/objectRestForOf.ts ===
+let array: { x: number, y: string }[];
+>array : { x: number; y: string; }[]
+>x : number
+>y : string
+
+for (let { x, ...restOf } of array) {
+>x : number
+>restOf : { y: string; }
+>array : { x: number; y: string; }[]
+
+    [x, restOf];
+>[x, restOf] : (number | { y: string; })[]
+>x : number
+>restOf : { y: string; }
+}
+let xx: number;
+>xx : number
+
+let rrestOff: { y: string };
+>rrestOff : { y: string; }
+>y : string
+
+for ({ x: xx, ...rrestOff } of array ) {
+>{ x: xx, ...rrestOff } : { y: string; x: number; }
+>x : { x: number; y: string; }
+>xx : number
+>rrestOff : any
+>array : { x: number; y: string; }[]
+
+    [xx, rrestOff];
+>[xx, rrestOff] : (number | { y: string; })[]
+>xx : number
+>rrestOff : { y: string; }
+}
+for (const norest of array.map(a => ({ ...a, x: 'a string' }))) {
+>norest : { x: string; y: string; }
+>array.map(a => ({ ...a, x: 'a string' })) : { x: string; y: string; }[]
+>array.map : { <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): U[]; }
+>array : { x: number; y: string; }[]
+>map : { <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U, U]; <U>(this: [{ x: number; y: string; }, { x: number; y: string; }], callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: { x: number; y: string; }, index: number, array: { x: number; y: string; }[]) => U, thisArg?: any): U[]; }
+>a => ({ ...a, x: 'a string' }) : (a: { x: number; y: string; }) => { x: string; y: string; }
+>a : { x: number; y: string; }
+>({ ...a, x: 'a string' }) : { x: string; y: string; }
+>{ ...a, x: 'a string' } : { x: string; y: string; }
+>a : any
+>x : string
+>'a string' : "a string"
+
+    [norest.x, norest.y];
+>[norest.x, norest.y] : string[]
+>norest.x : string
+>norest : { x: string; y: string; }
+>x : string
+>norest.y : string
+>norest : { x: string; y: string; }
+>y : string
+
+    // x is now a string. who knows why.
+}
+

tests/baselines/reference/objectRestNegative.errors.txt

@@ -0,0 +1,21 @@
+tests/cases/conformance/types/rest/objectRestNegative.ts(2,10): error TS2462: A rest element must be last in a destructuring pattern
+tests/cases/conformance/types/rest/objectRestNegative.ts(3,31): error TS2462: A rest element must be last in a destructuring pattern
+tests/cases/conformance/types/rest/objectRestNegative.ts(6,17): error TS2700: Rest types may only be created from object types.
+
+
+==== tests/cases/conformance/types/rest/objectRestNegative.ts (3 errors) ====
+    let o = { a: 1, b: 'no' };
+    var { ...mustBeLast, a } = o;
+             ~~~~~~~~~~
+!!! error TS2462: A rest element must be last in a destructuring pattern
+    function stillMustBeLast({ ...mustBeLast, a }: { a: number, b: string }): void {
+                                  ~~~~~~~~~~
+!!! error TS2462: A rest element must be last in a destructuring pattern
+    }
+    function generic<T extends { x, y }>(t: T) {
+        let { x, ...rest } = t;
+                    ~~~~
+!!! error TS2700: Rest types may only be created from object types.
+        return rest;
+    }
+    

tests/baselines/reference/objectRestNegative.js

@@ -0,0 +1,27 @@
+//// [objectRestNegative.ts]
+let o = { a: 1, b: 'no' };
+var { ...mustBeLast, a } = o;
+function stillMustBeLast({ ...mustBeLast, a }: { a: number, b: string }): void {
+}
+function generic<T extends { x, y }>(t: T) {
+    let { x, ...rest } = t;
+    return rest;
+}
+
+
+//// [objectRestNegative.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+var o = { a: 1, b: 'no' };
+var mustBeLast = o.mustBeLast, a = o.a;
+function stillMustBeLast(_a) {
+    var mustBeLast = _a.mustBeLast, a = _a.a;
+}
+function generic(t) {
+    var x = t.x, rest = __rest(t, ["x"]);
+    return rest;
+}

tests/baselines/reference/objectRestParameter.js

@@ -0,0 +1,28 @@
+//// [objectRestParameter.ts]
+function cloneAgain({ a, ...clone }: { a: number, b: string }): void {
+}
+
+declare function suddenly(f: (a: { x: { z, ka }, y: string }) => void);
+suddenly(({ x: a, ...rest }) => rest.y);
+suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka);
+
+
+
+//// [objectRestParameter.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
+        t[p] = s[p];
+    return t;
+};
+function cloneAgain(_a) {
+    var { a } = _a, clone = __rest(_a, ["a"]);
+}
+suddenly((_a) => {
+    var { x: a } = _a, rest = __rest(_a, ["x"]);
+    return rest.y;
+});
+suddenly((_a = { x: { z: 1, ka: 1 }, y: 'noo' }) => {
+    var _b = _a.x, { z = 12 } = _b, nested = __rest(_b, ["z"]), rest = __rest(_a, ["x"]);
+    return rest.y + nested.ka;
+});

tests/baselines/reference/objectRestParameter.symbols

@@ -0,0 +1,45 @@
+=== tests/cases/conformance/types/rest/objectRestParameter.ts ===
+function cloneAgain({ a, ...clone }: { a: number, b: string }): void {
+>cloneAgain : Symbol(cloneAgain, Decl(objectRestParameter.ts, 0, 0))
+>a : Symbol(a, Decl(objectRestParameter.ts, 0, 21))
+>clone : Symbol(clone, Decl(objectRestParameter.ts, 0, 24))
+>a : Symbol(a, Decl(objectRestParameter.ts, 0, 38))
+>b : Symbol(b, Decl(objectRestParameter.ts, 0, 49))
+}
+
+declare function suddenly(f: (a: { x: { z, ka }, y: string }) => void);
+>suddenly : Symbol(suddenly, Decl(objectRestParameter.ts, 1, 1))
+>f : Symbol(f, Decl(objectRestParameter.ts, 3, 26))
+>a : Symbol(a, Decl(objectRestParameter.ts, 3, 30))
+>x : Symbol(x, Decl(objectRestParameter.ts, 3, 34))
+>z : Symbol(z, Decl(objectRestParameter.ts, 3, 39))
+>ka : Symbol(ka, Decl(objectRestParameter.ts, 3, 42))
+>y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+
+suddenly(({ x: a, ...rest }) => rest.y);
+>suddenly : Symbol(suddenly, Decl(objectRestParameter.ts, 1, 1))
+>x : Symbol(x, Decl(objectRestParameter.ts, 3, 34))
+>a : Symbol(a, Decl(objectRestParameter.ts, 4, 11))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 4, 17))
+>rest.y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 4, 17))
+>y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+
+suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka);
+>suddenly : Symbol(suddenly, Decl(objectRestParameter.ts, 1, 1))
+>x : Symbol(x, Decl(objectRestParameter.ts, 3, 34))
+>z : Symbol(z, Decl(objectRestParameter.ts, 5, 16))
+>nested : Symbol(nested, Decl(objectRestParameter.ts, 5, 24))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 5, 37))
+>x : Symbol(x, Decl(objectRestParameter.ts, 5, 51))
+>z : Symbol(z, Decl(objectRestParameter.ts, 5, 56))
+>ka : Symbol(ka, Decl(objectRestParameter.ts, 5, 62))
+>y : Symbol(y, Decl(objectRestParameter.ts, 5, 71))
+>rest.y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+>rest : Symbol(rest, Decl(objectRestParameter.ts, 5, 37))
+>y : Symbol(y, Decl(objectRestParameter.ts, 3, 48))
+>nested.ka : Symbol(ka, Decl(objectRestParameter.ts, 3, 42))
+>nested : Symbol(nested, Decl(objectRestParameter.ts, 5, 24))
+>ka : Symbol(ka, Decl(objectRestParameter.ts, 3, 42))
+
+

tests/baselines/reference/objectRestParameter.types

@@ -0,0 +1,56 @@
+=== tests/cases/conformance/types/rest/objectRestParameter.ts ===
+function cloneAgain({ a, ...clone }: { a: number, b: string }): void {
+>cloneAgain : ({a, ...clone}: { a: number; b: string; }) => void
+>a : number
+>clone : { b: string; }
+>a : number
+>b : string
+}
+
+declare function suddenly(f: (a: { x: { z, ka }, y: string }) => void);
+>suddenly : (f: (a: { x: { z: any; ka: any; }; y: string; }) => void) => any
+>f : (a: { x: { z: any; ka: any; }; y: string; }) => void
+>a : { x: { z: any; ka: any; }; y: string; }
+>x : { z: any; ka: any; }
+>z : any
+>ka : any
+>y : string
+
+suddenly(({ x: a, ...rest }) => rest.y);
+>suddenly(({ x: a, ...rest }) => rest.y) : any
+>suddenly : (f: (a: { x: { z: any; ka: any; }; y: string; }) => void) => any
+>({ x: a, ...rest }) => rest.y : ({x: a, ...rest}: { x: { z: any; ka: any; }; y: string; }) => string
+>x : any
+>a : { z: any; ka: any; }
+>rest : { y: string; }
+>rest.y : string
+>rest : { y: string; }
+>y : string
+
+suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka);
+>suddenly(({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka) : any
+>suddenly : (f: (a: { x: { z: any; ka: any; }; y: string; }) => void) => any
+>({ x: { z = 12, ...nested }, ...rest } = { x: { z: 1, ka: 1 }, y: 'noo' }) => rest.y + nested.ka : ({x: {z, ...nested}, ...rest}?: { x: { z: any; ka: any; }; y: string; }) => string
+>x : any
+>z : any
+>12 : 12
+>nested : { ka: any; }
+>rest : { y: string; }
+>{ x: { z: 1, ka: 1 }, y: 'noo' } : { x: { z: number; ka: number; }; y: string; }
+>x : { z: number; ka: number; }
+>{ z: 1, ka: 1 } : { z: number; ka: number; }
+>z : number
+>1 : 1
+>ka : number
+>1 : 1
+>y : string
+>'noo' : "noo"
+>rest.y + nested.ka : string
+>rest.y : string
+>rest : { y: string; }
+>y : string
+>nested.ka : any
+>nested : { ka: any; }
+>ka : any
+
+

tests/baselines/reference/objectSpread.js

@@ -0,0 +1,151 @@
+//// [objectSpread.ts]
+let o = { a: 1, b: 'no' }
+let o2 = { b: 'yes', c: true }
+let swap = { a: 'yes', b: -1 };
+
+let addAfter: { a: number, b: string, c: boolean } =
+    { ...o, c: false }
+let addBefore: { a: number, b: string, c: boolean } =
+    { c: false, ...o }
+// Note: ignore still changes the order that properties are printed
+let ignore: { a: number, b: string } =
+    { b: 'ignored', ...o }
+let override: { a: number, b: string } =
+    { ...o, b: 'override' }
+let nested: { a: number, b: boolean, c: string } =
+    { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
+let combined: { a: number, b: string, c: boolean } =
+    { ...o, ...o2 }
+let combinedBefore: { a: number, b: string, c: boolean } =
+    { b: 'ok', ...o, ...o2 }
+let combinedMid: { a: number, b: string, c: boolean } =
+    { ...o, b: 'ok', ...o2 }
+let combinedAfter: { a: number, b: string, c: boolean } =
+    { ...o, ...o2, b: 'ok' }
+let combinedNested: { a: number, b: boolean, c: string, d: string } =
+    { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
+let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+let propertyNested: { a: { a: number, b: string } } =
+    { a: { ... o } }
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+let op = { get a () { return 6 } };
+let getter: { a: number, c: number } =
+    { ...op, c: 7 }
+getter.a = 12;
+
+// functions result in { }
+let spreadFunc = { ...(function () { }) };
+
+// any results in any
+let anything: any;
+let spreadAny = { ...anything };
+
+// methods are not enumerable
+class C { p = 1; m() { } }
+let c: C = new C()
+let spreadC: { p: number } = { ...c }
+
+// own methods are enumerable
+let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
+cplus.plus();
+
+// new field's type conflicting with existing field is OK
+let changeTypeAfter: { a: string, b: string } =
+    { ...o, a: 'wrong type?' }
+let changeTypeBefore: { a: number, b: string } =
+    { a: 'wrong type?', ...o };
+let changeTypeBoth: { a: string, b: number } =
+    { ...o, ...swap };
+
+// optional
+let definiteBoolean: { sn: boolean };
+let definiteString: { sn: string };
+let optionalString: { sn?: string };
+let optionalNumber: { sn?: number };
+let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+
+// computed property
+let computedFirst: { a: number, b: string, "before everything": number } =
+    { ['before everything']: 12, ...o, b: 'yes' }
+let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
+    { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
+let computedAfter: { a: number, b: string, "at the end": number } =
+    { ...o, b: 'yeah', ['at the end']: 14 }
+// shortcut syntax
+let a = 12;
+let shortCutted: { a: number, b: string } = { ...o, a }
+
+
+
+//// [objectSpread.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var o = { a: 1, b: 'no' };
+var o2 = { b: 'yes', c: true };
+var swap = { a: 'yes', b: -1 };
+var addAfter = __assign({}, o, { c: false });
+var addBefore = __assign({ c: false }, o);
+// Note: ignore still changes the order that properties are printed
+var ignore = __assign({ b: 'ignored' }, o);
+var override = __assign({}, o, { b: 'override' });
+var nested = __assign({}, __assign({ a: 3 }, { b: false, c: 'overriden' }), { c: 'whatever' });
+var combined = __assign({}, o, o2);
+var combinedBefore = __assign({ b: 'ok' }, o, o2);
+var combinedMid = __assign({}, o, { b: 'ok' }, o2);
+var combinedAfter = __assign({}, o, o2, { b: 'ok' });
+var combinedNested = __assign({}, __assign({ a: 4 }, { b: false, c: 'overriden' }), { d: 'actually new' }, { a: 5, d: 'maybe new' });
+var combinedNestedChangeType = __assign({}, __assign({ a: 1 }, { b: false, c: 'overriden' }), { c: -1 });
+var propertyNested = __assign({ a: __assign({}, o) });
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+var op = { get a() { return 6; } };
+var getter = __assign({}, op, { c: 7 });
+getter.a = 12;
+// functions result in { }
+var spreadFunc = __assign({}, (function () { }));
+// any results in any
+var anything;
+var spreadAny = __assign({}, anything);
+// methods are not enumerable
+var C = (function () {
+    function C() {
+        this.p = 1;
+    }
+    C.prototype.m = function () { };
+    return C;
+}());
+var c = new C();
+var spreadC = __assign({}, c);
+// own methods are enumerable
+var cplus = __assign({}, c, { plus: function () { return this.p + 1; } });
+cplus.plus();
+// new field's type conflicting with existing field is OK
+var changeTypeAfter = __assign({}, o, { a: 'wrong type?' });
+var changeTypeBefore = __assign({ a: 'wrong type?' }, o);
+var changeTypeBoth = __assign({}, o, swap);
+// optional
+var definiteBoolean;
+var definiteString;
+var optionalString;
+var optionalNumber;
+var optionalUnionStops = __assign({}, definiteBoolean, definiteString, optionalNumber);
+var optionalUnionDuplicates = __assign({}, definiteBoolean, definiteString, optionalString, optionalNumber);
+var allOptional = __assign({}, optionalString, optionalNumber);
+// computed property
+var computedFirst = __assign((_a = {}, _a['before everything'] = 12, _a), o, { b: 'yes' });
+var computedMiddle = __assign({}, o, (_b = {}, _b['in the middle'] = 13, _b.b = 'maybe?', _b), o2);
+var computedAfter = __assign({}, o, (_c = { b: 'yeah' }, _c['at the end'] = 14, _c));
+// shortcut syntax
+var a = 12;
+var shortCutted = __assign({}, o, { a: a });
+var _a, _b, _c;

tests/baselines/reference/objectSpread.symbols

@@ -0,0 +1,284 @@
+=== tests/cases/conformance/types/spread/objectSpread.ts ===
+let o = { a: 1, b: 'no' }
+>o : Symbol(o, Decl(objectSpread.ts, 0, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 0, 9))
+>b : Symbol(b, Decl(objectSpread.ts, 0, 15))
+
+let o2 = { b: 'yes', c: true }
+>o2 : Symbol(o2, Decl(objectSpread.ts, 1, 3))
+>b : Symbol(b, Decl(objectSpread.ts, 1, 10))
+>c : Symbol(c, Decl(objectSpread.ts, 1, 20))
+
+let swap = { a: 'yes', b: -1 };
+>swap : Symbol(swap, Decl(objectSpread.ts, 2, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 2, 12))
+>b : Symbol(b, Decl(objectSpread.ts, 2, 22))
+
+let addAfter: { a: number, b: string, c: boolean } =
+>addAfter : Symbol(addAfter, Decl(objectSpread.ts, 4, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 4, 15))
+>b : Symbol(b, Decl(objectSpread.ts, 4, 26))
+>c : Symbol(c, Decl(objectSpread.ts, 4, 37))
+
+    { ...o, c: false }
+>c : Symbol(c, Decl(objectSpread.ts, 5, 11))
+
+let addBefore: { a: number, b: string, c: boolean } =
+>addBefore : Symbol(addBefore, Decl(objectSpread.ts, 6, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 6, 16))
+>b : Symbol(b, Decl(objectSpread.ts, 6, 27))
+>c : Symbol(c, Decl(objectSpread.ts, 6, 38))
+
+    { c: false, ...o }
+>c : Symbol(c, Decl(objectSpread.ts, 7, 5))
+
+// Note: ignore still changes the order that properties are printed
+let ignore: { a: number, b: string } =
+>ignore : Symbol(ignore, Decl(objectSpread.ts, 9, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 9, 13))
+>b : Symbol(b, Decl(objectSpread.ts, 9, 24))
+
+    { b: 'ignored', ...o }
+>b : Symbol(b, Decl(objectSpread.ts, 10, 5))
+
+let override: { a: number, b: string } =
+>override : Symbol(override, Decl(objectSpread.ts, 11, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 11, 15))
+>b : Symbol(b, Decl(objectSpread.ts, 11, 26))
+
+    { ...o, b: 'override' }
+>b : Symbol(b, Decl(objectSpread.ts, 12, 11))
+
+let nested: { a: number, b: boolean, c: string } =
+>nested : Symbol(nested, Decl(objectSpread.ts, 13, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 13, 13))
+>b : Symbol(b, Decl(objectSpread.ts, 13, 24))
+>c : Symbol(c, Decl(objectSpread.ts, 13, 36))
+
+    { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
+>a : Symbol(a, Decl(objectSpread.ts, 14, 10))
+>b : Symbol(b, Decl(objectSpread.ts, 14, 21))
+>c : Symbol(c, Decl(objectSpread.ts, 14, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 14, 51))
+
+let combined: { a: number, b: string, c: boolean } =
+>combined : Symbol(combined, Decl(objectSpread.ts, 15, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 15, 15))
+>b : Symbol(b, Decl(objectSpread.ts, 15, 26))
+>c : Symbol(c, Decl(objectSpread.ts, 15, 37))
+
+    { ...o, ...o2 }
+let combinedBefore: { a: number, b: string, c: boolean } =
+>combinedBefore : Symbol(combinedBefore, Decl(objectSpread.ts, 17, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 17, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 17, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 17, 43))
+
+    { b: 'ok', ...o, ...o2 }
+>b : Symbol(b, Decl(objectSpread.ts, 18, 5))
+
+let combinedMid: { a: number, b: string, c: boolean } =
+>combinedMid : Symbol(combinedMid, Decl(objectSpread.ts, 19, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 19, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 19, 29))
+>c : Symbol(c, Decl(objectSpread.ts, 19, 40))
+
+    { ...o, b: 'ok', ...o2 }
+>b : Symbol(b, Decl(objectSpread.ts, 20, 11))
+
+let combinedAfter: { a: number, b: string, c: boolean } =
+>combinedAfter : Symbol(combinedAfter, Decl(objectSpread.ts, 21, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 21, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 21, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 21, 42))
+
+    { ...o, ...o2, b: 'ok' }
+>b : Symbol(b, Decl(objectSpread.ts, 22, 18))
+
+let combinedNested: { a: number, b: boolean, c: string, d: string } =
+>combinedNested : Symbol(combinedNested, Decl(objectSpread.ts, 23, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 23, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 23, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 23, 44))
+>d : Symbol(d, Decl(objectSpread.ts, 23, 55))
+
+    { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
+>a : Symbol(a, Decl(objectSpread.ts, 24, 10))
+>b : Symbol(b, Decl(objectSpread.ts, 24, 21))
+>c : Symbol(c, Decl(objectSpread.ts, 24, 31))
+>d : Symbol(d, Decl(objectSpread.ts, 24, 51))
+>a : Symbol(a, Decl(objectSpread.ts, 24, 75))
+>d : Symbol(d, Decl(objectSpread.ts, 24, 81))
+
+let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+>combinedNestedChangeType : Symbol(combinedNestedChangeType, Decl(objectSpread.ts, 25, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 25, 31))
+>b : Symbol(b, Decl(objectSpread.ts, 25, 42))
+>c : Symbol(c, Decl(objectSpread.ts, 25, 54))
+
+    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+>a : Symbol(a, Decl(objectSpread.ts, 26, 10))
+>b : Symbol(b, Decl(objectSpread.ts, 26, 21))
+>c : Symbol(c, Decl(objectSpread.ts, 26, 31))
+>c : Symbol(c, Decl(objectSpread.ts, 26, 51))
+
+let propertyNested: { a: { a: number, b: string } } =
+>propertyNested : Symbol(propertyNested, Decl(objectSpread.ts, 27, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 27, 21))
+>a : Symbol(a, Decl(objectSpread.ts, 27, 26))
+>b : Symbol(b, Decl(objectSpread.ts, 27, 37))
+
+    { a: { ... o } }
+>a : Symbol(a, Decl(objectSpread.ts, 28, 5))
+
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+let op = { get a () { return 6 } };
+>op : Symbol(op, Decl(objectSpread.ts, 31, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 31, 10))
+
+let getter: { a: number, c: number } =
+>getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 32, 13))
+>c : Symbol(c, Decl(objectSpread.ts, 32, 24))
+
+    { ...op, c: 7 }
+>c : Symbol(c, Decl(objectSpread.ts, 33, 12))
+
+getter.a = 12;
+>getter.a : Symbol(a, Decl(objectSpread.ts, 32, 13))
+>getter : Symbol(getter, Decl(objectSpread.ts, 32, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 32, 13))
+
+// functions result in { }
+let spreadFunc = { ...(function () { }) };
+>spreadFunc : Symbol(spreadFunc, Decl(objectSpread.ts, 37, 3))
+
+// any results in any
+let anything: any;
+>anything : Symbol(anything, Decl(objectSpread.ts, 40, 3))
+
+let spreadAny = { ...anything };
+>spreadAny : Symbol(spreadAny, Decl(objectSpread.ts, 41, 3))
+
+// methods are not enumerable
+class C { p = 1; m() { } }
+>C : Symbol(C, Decl(objectSpread.ts, 41, 32))
+>p : Symbol(C.p, Decl(objectSpread.ts, 44, 9))
+>m : Symbol(C.m, Decl(objectSpread.ts, 44, 16))
+
+let c: C = new C()
+>c : Symbol(c, Decl(objectSpread.ts, 45, 3))
+>C : Symbol(C, Decl(objectSpread.ts, 41, 32))
+>C : Symbol(C, Decl(objectSpread.ts, 41, 32))
+
+let spreadC: { p: number } = { ...c }
+>spreadC : Symbol(spreadC, Decl(objectSpread.ts, 46, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 46, 14))
+
+// own methods are enumerable
+let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 49, 3))
+>p : Symbol(p, Decl(objectSpread.ts, 49, 12))
+>plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
+>plus : Symbol(plus, Decl(objectSpread.ts, 49, 48))
+>this : Symbol(__object, Decl(objectSpread.ts, 41, 15))
+
+cplus.plus();
+>cplus.plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
+>cplus : Symbol(cplus, Decl(objectSpread.ts, 49, 3))
+>plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
+
+// new field's type conflicting with existing field is OK
+let changeTypeAfter: { a: string, b: string } =
+>changeTypeAfter : Symbol(changeTypeAfter, Decl(objectSpread.ts, 53, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 53, 22))
+>b : Symbol(b, Decl(objectSpread.ts, 53, 33))
+
+    { ...o, a: 'wrong type?' }
+>a : Symbol(a, Decl(objectSpread.ts, 54, 11))
+
+let changeTypeBefore: { a: number, b: string } =
+>changeTypeBefore : Symbol(changeTypeBefore, Decl(objectSpread.ts, 55, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 55, 23))
+>b : Symbol(b, Decl(objectSpread.ts, 55, 34))
+
+    { a: 'wrong type?', ...o };
+>a : Symbol(a, Decl(objectSpread.ts, 56, 5))
+
+let changeTypeBoth: { a: string, b: number } =
+>changeTypeBoth : Symbol(changeTypeBoth, Decl(objectSpread.ts, 57, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 57, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 57, 32))
+
+    { ...o, ...swap };
+
+// optional
+let definiteBoolean: { sn: boolean };
+>definiteBoolean : Symbol(definiteBoolean, Decl(objectSpread.ts, 61, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 61, 22))
+
+let definiteString: { sn: string };
+>definiteString : Symbol(definiteString, Decl(objectSpread.ts, 62, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 62, 21))
+
+let optionalString: { sn?: string };
+>optionalString : Symbol(optionalString, Decl(objectSpread.ts, 63, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 63, 21))
+
+let optionalNumber: { sn?: number };
+>optionalNumber : Symbol(optionalNumber, Decl(objectSpread.ts, 64, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 64, 21))
+
+let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+>optionalUnionStops : Symbol(optionalUnionStops, Decl(objectSpread.ts, 65, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 65, 25))
+
+let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+>optionalUnionDuplicates : Symbol(optionalUnionDuplicates, Decl(objectSpread.ts, 66, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 66, 30))
+
+let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+>allOptional : Symbol(allOptional, Decl(objectSpread.ts, 67, 3))
+>sn : Symbol(sn, Decl(objectSpread.ts, 67, 18))
+
+// computed property
+let computedFirst: { a: number, b: string, "before everything": number } =
+>computedFirst : Symbol(computedFirst, Decl(objectSpread.ts, 70, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 70, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 70, 31))
+
+    { ['before everything']: 12, ...o, b: 'yes' }
+>'before everything' : Symbol(['before everything'], Decl(objectSpread.ts, 71, 5))
+>b : Symbol(b, Decl(objectSpread.ts, 71, 38))
+
+let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
+>computedMiddle : Symbol(computedMiddle, Decl(objectSpread.ts, 72, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 72, 21))
+>b : Symbol(b, Decl(objectSpread.ts, 72, 32))
+>c : Symbol(c, Decl(objectSpread.ts, 72, 43))
+
+    { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
+>'in the middle' : Symbol(['in the middle'], Decl(objectSpread.ts, 73, 11))
+>b : Symbol(b, Decl(objectSpread.ts, 73, 34))
+
+let computedAfter: { a: number, b: string, "at the end": number } =
+>computedAfter : Symbol(computedAfter, Decl(objectSpread.ts, 74, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 74, 20))
+>b : Symbol(b, Decl(objectSpread.ts, 74, 31))
+
+    { ...o, b: 'yeah', ['at the end']: 14 }
+>b : Symbol(b, Decl(objectSpread.ts, 75, 11))
+>'at the end' : Symbol(['at the end'], Decl(objectSpread.ts, 75, 22))
+
+// shortcut syntax
+let a = 12;
+>a : Symbol(a, Decl(objectSpread.ts, 77, 3))
+
+let shortCutted: { a: number, b: string } = { ...o, a }
+>shortCutted : Symbol(shortCutted, Decl(objectSpread.ts, 78, 3))
+>a : Symbol(a, Decl(objectSpread.ts, 78, 18))
+>b : Symbol(b, Decl(objectSpread.ts, 78, 29))
+>a : Symbol(a, Decl(objectSpread.ts, 78, 51))
+
+

tests/baselines/reference/objectSpread.types

@@ -0,0 +1,410 @@
+=== tests/cases/conformance/types/spread/objectSpread.ts ===
+let o = { a: 1, b: 'no' }
+>o : { a: number; b: string; }
+>{ a: 1, b: 'no' } : { a: number; b: string; }
+>a : number
+>1 : 1
+>b : string
+>'no' : "no"
+
+let o2 = { b: 'yes', c: true }
+>o2 : { b: string; c: boolean; }
+>{ b: 'yes', c: true } : { b: string; c: boolean; }
+>b : string
+>'yes' : "yes"
+>c : boolean
+>true : true
+
+let swap = { a: 'yes', b: -1 };
+>swap : { a: string; b: number; }
+>{ a: 'yes', b: -1 } : { a: string; b: number; }
+>a : string
+>'yes' : "yes"
+>b : number
+>-1 : -1
+>1 : 1
+
+let addAfter: { a: number, b: string, c: boolean } =
+>addAfter : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, c: false }
+>{ ...o, c: false } : { c: false; a: number; b: string; }
+>o : any
+>c : boolean
+>false : false
+
+let addBefore: { a: number, b: string, c: boolean } =
+>addBefore : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { c: false, ...o }
+>{ c: false, ...o } : { a: number; b: string; c: false; }
+>c : boolean
+>false : false
+>o : any
+
+// Note: ignore still changes the order that properties are printed
+let ignore: { a: number, b: string } =
+>ignore : { a: number; b: string; }
+>a : number
+>b : string
+
+    { b: 'ignored', ...o }
+>{ b: 'ignored', ...o } : { a: number; b: string; }
+>b : string
+>'ignored' : "ignored"
+>o : any
+
+let override: { a: number, b: string } =
+>override : { a: number; b: string; }
+>a : number
+>b : string
+
+    { ...o, b: 'override' }
+>{ ...o, b: 'override' } : { b: string; a: number; }
+>o : any
+>b : string
+>'override' : "override"
+
+let nested: { a: number, b: boolean, c: string } =
+>nested : { a: number; b: boolean; c: string; }
+>a : number
+>b : boolean
+>c : string
+
+    { ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' }
+>{ ...{ a: 3, ...{ b: false, c: 'overriden' } }, c: 'whatever' } : { c: string; b: boolean; a: number; }
+>{ a: 3, ...{ b: false, c: 'overriden' } } : { b: boolean; c: string; a: number; }
+>a : number
+>3 : 3
+>{ b: false, c: 'overriden' } : { b: boolean; c: string; }
+>b : boolean
+>false : false
+>c : string
+>'overriden' : "overriden"
+>c : string
+>'whatever' : "whatever"
+
+let combined: { a: number, b: string, c: boolean } =
+>combined : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, ...o2 }
+>{ ...o, ...o2 } : { b: string; c: boolean; a: number; }
+>o : any
+>o2 : any
+
+let combinedBefore: { a: number, b: string, c: boolean } =
+>combinedBefore : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { b: 'ok', ...o, ...o2 }
+>{ b: 'ok', ...o, ...o2 } : { b: string; c: boolean; a: number; }
+>b : string
+>'ok' : "ok"
+>o : any
+>o2 : any
+
+let combinedMid: { a: number, b: string, c: boolean } =
+>combinedMid : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, b: 'ok', ...o2 }
+>{ ...o, b: 'ok', ...o2 } : { b: string; c: boolean; a: number; }
+>o : any
+>b : string
+>'ok' : "ok"
+>o2 : any
+
+let combinedAfter: { a: number, b: string, c: boolean } =
+>combinedAfter : { a: number; b: string; c: boolean; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, ...o2, b: 'ok' }
+>{ ...o, ...o2, b: 'ok' } : { b: string; c: boolean; a: number; }
+>o : any
+>o2 : any
+>b : string
+>'ok' : "ok"
+
+let combinedNested: { a: number, b: boolean, c: string, d: string } =
+>combinedNested : { a: number; b: boolean; c: string; d: string; }
+>a : number
+>b : boolean
+>c : string
+>d : string
+
+    { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
+>{ ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } } : { a: number; d: string; b: boolean; c: string; }
+>{ a: 4, ...{ b: false, c: 'overriden' } } : { b: boolean; c: string; a: number; }
+>a : number
+>4 : 4
+>{ b: false, c: 'overriden' } : { b: boolean; c: string; }
+>b : boolean
+>false : false
+>c : string
+>'overriden' : "overriden"
+>d : string
+>'actually new' : "actually new"
+>{ a: 5, d: 'maybe new' } : { a: number; d: string; }
+>a : number
+>5 : 5
+>d : string
+>'maybe new' : "maybe new"
+
+let combinedNestedChangeType: { a: number, b: boolean, c: number } =
+>combinedNestedChangeType : { a: number; b: boolean; c: number; }
+>a : number
+>b : boolean
+>c : number
+
+    { ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 }
+>{ ...{ a: 1, ...{ b: false, c: 'overriden' } }, c: -1 } : { c: number; b: boolean; a: number; }
+>{ a: 1, ...{ b: false, c: 'overriden' } } : { b: boolean; c: string; a: number; }
+>a : number
+>1 : 1
+>{ b: false, c: 'overriden' } : { b: boolean; c: string; }
+>b : boolean
+>false : false
+>c : string
+>'overriden' : "overriden"
+>c : number
+>-1 : -1
+>1 : 1
+
+let propertyNested: { a: { a: number, b: string } } =
+>propertyNested : { a: { a: number; b: string; }; }
+>a : { a: number; b: string; }
+>a : number
+>b : string
+
+    { a: { ... o } }
+>{ a: { ... o } } : { a: { a: number; b: string; }; }
+>a : { a: number; b: string; }
+>{ ... o } : { a: number; b: string; }
+>o : any
+
+// accessors don't copy the descriptor
+// (which means that readonly getters become read/write properties)
+let op = { get a () { return 6 } };
+>op : { readonly a: number; }
+>{ get a () { return 6 } } : { readonly a: number; }
+>a : number
+>6 : 6
+
+let getter: { a: number, c: number } =
+>getter : { a: number; c: number; }
+>a : number
+>c : number
+
+    { ...op, c: 7 }
+>{ ...op, c: 7 } : { c: number; readonly a: number; }
+>op : any
+>c : number
+>7 : 7
+
+getter.a = 12;
+>getter.a = 12 : 12
+>getter.a : number
+>getter : { a: number; c: number; }
+>a : number
+>12 : 12
+
+// functions result in { }
+let spreadFunc = { ...(function () { }) };
+>spreadFunc : {}
+>{ ...(function () { }) } : {}
+>(function () { }) : () => void
+>function () { } : () => void
+
+// any results in any
+let anything: any;
+>anything : any
+
+let spreadAny = { ...anything };
+>spreadAny : any
+>{ ...anything } : any
+>anything : any
+
+// methods are not enumerable
+class C { p = 1; m() { } }
+>C : C
+>p : number
+>1 : 1
+>m : () => void
+
+let c: C = new C()
+>c : C
+>C : C
+>new C() : C
+>C : typeof C
+
+let spreadC: { p: number } = { ...c }
+>spreadC : { p: number; }
+>p : number
+>{ ...c } : { p: number; }
+>c : any
+
+// own methods are enumerable
+let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } };
+>cplus : { p: number; plus(): void; }
+>p : number
+>plus : () => void
+>{ ...c, plus() { return this.p + 1; } } : { plus(): any; p: number; }
+>c : any
+>plus : () => any
+>this.p + 1 : any
+>this.p : any
+>this : any
+>p : any
+>1 : 1
+
+cplus.plus();
+>cplus.plus() : void
+>cplus.plus : () => void
+>cplus : { p: number; plus(): void; }
+>plus : () => void
+
+// new field's type conflicting with existing field is OK
+let changeTypeAfter: { a: string, b: string } =
+>changeTypeAfter : { a: string; b: string; }
+>a : string
+>b : string
+
+    { ...o, a: 'wrong type?' }
+>{ ...o, a: 'wrong type?' } : { a: string; b: string; }
+>o : any
+>a : string
+>'wrong type?' : "wrong type?"
+
+let changeTypeBefore: { a: number, b: string } =
+>changeTypeBefore : { a: number; b: string; }
+>a : number
+>b : string
+
+    { a: 'wrong type?', ...o };
+>{ a: 'wrong type?', ...o } : { a: number; b: string; }
+>a : string
+>'wrong type?' : "wrong type?"
+>o : any
+
+let changeTypeBoth: { a: string, b: number } =
+>changeTypeBoth : { a: string; b: number; }
+>a : string
+>b : number
+
+    { ...o, ...swap };
+>{ ...o, ...swap } : { a: string; b: number; }
+>o : any
+>swap : any
+
+// optional
+let definiteBoolean: { sn: boolean };
+>definiteBoolean : { sn: boolean; }
+>sn : boolean
+
+let definiteString: { sn: string };
+>definiteString : { sn: string; }
+>sn : string
+
+let optionalString: { sn?: string };
+>optionalString : { sn?: string; }
+>sn : string
+
+let optionalNumber: { sn?: number };
+>optionalNumber : { sn?: number; }
+>sn : number
+
+let optionalUnionStops: { sn: string | number | boolean } = { ...definiteBoolean, ...definiteString, ...optionalNumber };
+>optionalUnionStops : { sn: string | number | boolean; }
+>sn : string | number | boolean
+>{ ...definiteBoolean, ...definiteString, ...optionalNumber } : { sn: string | number; }
+>definiteBoolean : any
+>definiteString : any
+>optionalNumber : any
+
+let optionalUnionDuplicates: { sn: string | number } = { ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber };
+>optionalUnionDuplicates : { sn: string | number; }
+>sn : string | number
+>{ ...definiteBoolean, ...definiteString, ...optionalString, ...optionalNumber } : { sn: string | number; }
+>definiteBoolean : any
+>definiteString : any
+>optionalString : any
+>optionalNumber : any
+
+let allOptional: { sn?: string | number } = { ...optionalString, ...optionalNumber };
+>allOptional : { sn?: string | number; }
+>sn : string | number
+>{ ...optionalString, ...optionalNumber } : { sn?: string | number; }
+>optionalString : any
+>optionalNumber : any
+
+// computed property
+let computedFirst: { a: number, b: string, "before everything": number } =
+>computedFirst : { a: number; b: string; "before everything": number; }
+>a : number
+>b : string
+
+    { ['before everything']: 12, ...o, b: 'yes' }
+>{ ['before everything']: 12, ...o, b: 'yes' } : { b: string; a: number; ['before everything']: number; }
+>'before everything' : "before everything"
+>12 : 12
+>o : any
+>b : string
+>'yes' : "yes"
+
+let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
+>computedMiddle : { a: number; b: string; c: boolean; "in the middle": number; }
+>a : number
+>b : string
+>c : boolean
+
+    { ...o, ['in the middle']: 13, b: 'maybe?', ...o2 }
+>{ ...o, ['in the middle']: 13, b: 'maybe?', ...o2 } : { b: string; c: boolean; ['in the middle']: number; a: number; }
+>o : any
+>'in the middle' : "in the middle"
+>13 : 13
+>b : string
+>'maybe?' : "maybe?"
+>o2 : any
+
+let computedAfter: { a: number, b: string, "at the end": number } =
+>computedAfter : { a: number; b: string; "at the end": number; }
+>a : number
+>b : string
+
+    { ...o, b: 'yeah', ['at the end']: 14 }
+>{ ...o, b: 'yeah', ['at the end']: 14 } : { b: string; ['at the end']: number; a: number; }
+>o : any
+>b : string
+>'yeah' : "yeah"
+>'at the end' : "at the end"
+>14 : 14
+
+// shortcut syntax
+let a = 12;
+>a : number
+>12 : 12
+
+let shortCutted: { a: number, b: string } = { ...o, a }
+>shortCutted : { a: number; b: string; }
+>a : number
+>b : string
+>{ ...o, a } : { a: number; b: string; }
+>o : any
+>a : number
+
+

tests/baselines/reference/objectSpreadIndexSignature.js

@@ -0,0 +1,36 @@
+//// [objectSpreadIndexSignature.ts]
+interface Indexed {
+    [n: string]: number;
+    a: number;
+}
+interface Indexed2 {
+    [n: string]: boolean;
+    c: boolean;
+}
+let indexed: Indexed;
+let indexed2: Indexed2;
+let i = { ...indexed, b: 11 };
+// only indexed has indexer, so i[101]: any
+i[101];
+let ii = { ...indexed, ...indexed2 };
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
+
+
+//// [objectSpreadIndexSignature.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+var indexed;
+var indexed2;
+var i = __assign({}, indexed, { b: 11 });
+// only indexed has indexer, so i[101]: any
+i[101];
+var ii = __assign({}, indexed, indexed2);
+// both have indexer, so i[1001]: number | boolean
+ii[1001];

tests/baselines/reference/objectSpreadIndexSignature.symbols

@@ -0,0 +1,42 @@
+=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
+interface Indexed {
+>Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 0, 0))
+
+    [n: string]: number;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 1, 5))
+
+    a: number;
+>a : Symbol(Indexed.a, Decl(objectSpreadIndexSignature.ts, 1, 24))
+}
+interface Indexed2 {
+>Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 3, 1))
+
+    [n: string]: boolean;
+>n : Symbol(n, Decl(objectSpreadIndexSignature.ts, 5, 5))
+
+    c: boolean;
+>c : Symbol(Indexed2.c, Decl(objectSpreadIndexSignature.ts, 5, 25))
+}
+let indexed: Indexed;
+>indexed : Symbol(indexed, Decl(objectSpreadIndexSignature.ts, 8, 3))
+>Indexed : Symbol(Indexed, Decl(objectSpreadIndexSignature.ts, 0, 0))
+
+let indexed2: Indexed2;
+>indexed2 : Symbol(indexed2, Decl(objectSpreadIndexSignature.ts, 9, 3))
+>Indexed2 : Symbol(Indexed2, Decl(objectSpreadIndexSignature.ts, 3, 1))
+
+let i = { ...indexed, b: 11 };
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 10, 3))
+>b : Symbol(b, Decl(objectSpreadIndexSignature.ts, 10, 21))
+
+// only indexed has indexer, so i[101]: any
+i[101];
+>i : Symbol(i, Decl(objectSpreadIndexSignature.ts, 10, 3))
+
+let ii = { ...indexed, ...indexed2 };
+>ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 13, 3))
+
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
+>ii : Symbol(ii, Decl(objectSpreadIndexSignature.ts, 13, 3))
+

tests/baselines/reference/objectSpreadIndexSignature.types

@@ -0,0 +1,52 @@
+=== tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts ===
+interface Indexed {
+>Indexed : Indexed
+
+    [n: string]: number;
+>n : string
+
+    a: number;
+>a : number
+}
+interface Indexed2 {
+>Indexed2 : Indexed2
+
+    [n: string]: boolean;
+>n : string
+
+    c: boolean;
+>c : boolean
+}
+let indexed: Indexed;
+>indexed : Indexed
+>Indexed : Indexed
+
+let indexed2: Indexed2;
+>indexed2 : Indexed2
+>Indexed2 : Indexed2
+
+let i = { ...indexed, b: 11 };
+>i : { b: number; a: number; }
+>{ ...indexed, b: 11 } : { b: number; a: number; }
+>indexed : any
+>b : number
+>11 : 11
+
+// only indexed has indexer, so i[101]: any
+i[101];
+>i[101] : any
+>i : { b: number; a: number; }
+>101 : 101
+
+let ii = { ...indexed, ...indexed2 };
+>ii : { [x: string]: number | boolean; c: boolean; a: number; }
+>{ ...indexed, ...indexed2 } : { [x: string]: number | boolean; c: boolean; a: number; }
+>indexed : any
+>indexed2 : any
+
+// both have indexer, so i[1001]: number | boolean
+ii[1001];
+>ii[1001] : number | boolean
+>ii : { [x: string]: number | boolean; c: boolean; a: number; }
+>1001 : 1001
+

tests/baselines/reference/objectSpreadInference.js

@@ -0,0 +1,43 @@
+//// [objectSpreadInference.ts]
+interface Result<T,U,V> {
+    t: T;
+    u: U;
+    v: V;
+}
+declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
+declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
+function generic<W, X, Y>(w: W, x: X, y: Y) {
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer({ ...w, ...x, a: y, b: "different type" });
+}
+let b: { b: number };
+let c: { c: number };
+// can only infer { t: {}, u: {}, v: {} }
+let i1 = infer({ ...b, ...c, a: 12 });
+// can only infer { t: {}, u: {}, v: {} }
+let i2 = infer2({ ...b, ...c, a: 12 });
+// can only infer { t: {}, u: {}, v: {} }
+let i3 = generic(b, c, { a: 12 });
+
+
+//// [objectSpreadInference.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+function generic(w, x, y) {
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer(__assign({}, w, x, { a: y, b: "different type" }));
+}
+var b;
+var c;
+// can only infer { t: {}, u: {}, v: {} }
+var i1 = infer(__assign({}, b, c, { a: 12 }));
+// can only infer { t: {}, u: {}, v: {} }
+var i2 = infer2(__assign({}, b, c, { a: 12 }));
+// can only infer { t: {}, u: {}, v: {} }
+var i3 = generic(b, c, { a: 12 });

tests/baselines/reference/objectSpreadInference.symbols

@@ -0,0 +1,100 @@
+=== tests/cases/conformance/types/spread/objectSpreadInference.ts ===
+interface Result<T,U,V> {
+>Result : Symbol(Result, Decl(objectSpreadInference.ts, 0, 0))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 0, 17))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 0, 19))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 0, 21))
+
+    t: T;
+>t : Symbol(Result.t, Decl(objectSpreadInference.ts, 0, 25))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 0, 17))
+
+    u: U;
+>u : Symbol(Result.u, Decl(objectSpreadInference.ts, 1, 9))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 0, 19))
+
+    v: V;
+>v : Symbol(Result.v, Decl(objectSpreadInference.ts, 2, 9))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 0, 21))
+}
+declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
+>infer : Symbol(infer, Decl(objectSpreadInference.ts, 4, 1))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 5, 23))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 5, 25))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 5, 27))
+>tuv : Symbol(tuv, Decl(objectSpreadInference.ts, 5, 30))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 5, 23))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 5, 25))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 5, 48))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 5, 27))
+>t : Symbol(t, Decl(objectSpreadInference.ts, 5, 59))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 5, 23))
+>u : Symbol(u, Decl(objectSpreadInference.ts, 5, 65))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 5, 25))
+>v : Symbol(v, Decl(objectSpreadInference.ts, 5, 71))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 5, 27))
+
+declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
+>infer2 : Symbol(infer2, Decl(objectSpreadInference.ts, 5, 79))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 6, 24))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 6, 26))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 6, 28))
+>utv : Symbol(utv, Decl(objectSpreadInference.ts, 6, 31))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 6, 26))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 6, 43))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 6, 28))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 6, 24))
+>t : Symbol(t, Decl(objectSpreadInference.ts, 6, 60))
+>T : Symbol(T, Decl(objectSpreadInference.ts, 6, 24))
+>u : Symbol(u, Decl(objectSpreadInference.ts, 6, 66))
+>U : Symbol(U, Decl(objectSpreadInference.ts, 6, 26))
+>v : Symbol(v, Decl(objectSpreadInference.ts, 6, 72))
+>V : Symbol(V, Decl(objectSpreadInference.ts, 6, 28))
+
+function generic<W, X, Y>(w: W, x: X, y: Y) {
+>generic : Symbol(generic, Decl(objectSpreadInference.ts, 6, 80))
+>W : Symbol(W, Decl(objectSpreadInference.ts, 7, 17))
+>X : Symbol(X, Decl(objectSpreadInference.ts, 7, 19))
+>Y : Symbol(Y, Decl(objectSpreadInference.ts, 7, 22))
+>w : Symbol(w, Decl(objectSpreadInference.ts, 7, 26))
+>W : Symbol(W, Decl(objectSpreadInference.ts, 7, 17))
+>x : Symbol(x, Decl(objectSpreadInference.ts, 7, 31))
+>X : Symbol(X, Decl(objectSpreadInference.ts, 7, 19))
+>y : Symbol(y, Decl(objectSpreadInference.ts, 7, 37))
+>Y : Symbol(Y, Decl(objectSpreadInference.ts, 7, 22))
+
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer({ ...w, ...x, a: y, b: "different type" });
+>infer : Symbol(infer, Decl(objectSpreadInference.ts, 4, 1))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 9, 30))
+>y : Symbol(y, Decl(objectSpreadInference.ts, 7, 37))
+>b : Symbol(b, Decl(objectSpreadInference.ts, 9, 36))
+}
+let b: { b: number };
+>b : Symbol(b, Decl(objectSpreadInference.ts, 11, 3))
+>b : Symbol(b, Decl(objectSpreadInference.ts, 11, 8))
+
+let c: { c: number };
+>c : Symbol(c, Decl(objectSpreadInference.ts, 12, 3))
+>c : Symbol(c, Decl(objectSpreadInference.ts, 12, 8))
+
+// can only infer { t: {}, u: {}, v: {} }
+let i1 = infer({ ...b, ...c, a: 12 });
+>i1 : Symbol(i1, Decl(objectSpreadInference.ts, 14, 3))
+>infer : Symbol(infer, Decl(objectSpreadInference.ts, 4, 1))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 14, 28))
+
+// can only infer { t: {}, u: {}, v: {} }
+let i2 = infer2({ ...b, ...c, a: 12 });
+>i2 : Symbol(i2, Decl(objectSpreadInference.ts, 16, 3))
+>infer2 : Symbol(infer2, Decl(objectSpreadInference.ts, 5, 79))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 16, 29))
+
+// can only infer { t: {}, u: {}, v: {} }
+let i3 = generic(b, c, { a: 12 });
+>i3 : Symbol(i3, Decl(objectSpreadInference.ts, 18, 3))
+>generic : Symbol(generic, Decl(objectSpreadInference.ts, 6, 80))
+>b : Symbol(b, Decl(objectSpreadInference.ts, 11, 3))
+>c : Symbol(c, Decl(objectSpreadInference.ts, 12, 3))
+>a : Symbol(a, Decl(objectSpreadInference.ts, 18, 24))
+

tests/baselines/reference/objectSpreadInference.types

@@ -0,0 +1,118 @@
+=== tests/cases/conformance/types/spread/objectSpreadInference.ts ===
+interface Result<T,U,V> {
+>Result : Result<T, U, V>
+>T : T
+>U : U
+>V : V
+
+    t: T;
+>t : T
+>T : T
+
+    u: U;
+>u : U
+>U : U
+
+    v: V;
+>v : V
+>V : V
+}
+declare function infer<T,U,V>(tuv: { ...T, ...U, a: V }): { t: T, u: U, v: V };
+>infer : <T, U, V>(tuv: { ...T; ...U; a: V; }) => { t: T; u: U; v: V; }
+>T : T
+>U : U
+>V : V
+>tuv : { ...T; ...U; a: V; }
+>T : T
+>U : U
+>a : V
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+declare function infer2<T,U,V>(utv: { ...U, a: V, ...T }): { t: T, u: U, v: V };
+>infer2 : <T, U, V>(utv: { ...U; a: V; ...T }) => { t: T; u: U; v: V; }
+>T : T
+>U : U
+>V : V
+>utv : { ...U; a: V; ...T }
+>U : U
+>a : V
+>V : V
+>T : T
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+function generic<W, X, Y>(w: W, x: X, y: Y) {
+>generic : <W, X, Y>(w: W, x: X, y: Y) => { t: {}; u: {}; v: {}; }
+>W : W
+>X : X
+>Y : Y
+>w : W
+>W : W
+>x : X
+>X : X
+>y : Y
+>Y : Y
+
+    // should infer { t: {}, u: {}, v: {} } because there is no trailing type parameter
+    return infer({ ...w, ...x, a: y, b: "different type" });
+>infer({ ...w, ...x, a: y, b: "different type" }) : { t: {}; u: {}; v: {}; }
+>infer : <T, U, V>(tuv: { ...T; ...U; a: V; }) => { t: T; u: U; v: V; }
+>{ ...w, ...x, a: y, b: "different type" } : { ...W; ...X; a: Y; b: string; }
+>w : any
+>x : any
+>a : Y
+>y : Y
+>b : string
+>"different type" : "different type"
+}
+let b: { b: number };
+>b : { b: number; }
+>b : number
+
+let c: { c: number };
+>c : { c: number; }
+>c : number
+
+// can only infer { t: {}, u: {}, v: {} }
+let i1 = infer({ ...b, ...c, a: 12 });
+>i1 : { t: {}; u: {}; v: {}; }
+>infer({ ...b, ...c, a: 12 }) : { t: {}; u: {}; v: {}; }
+>infer : <T, U, V>(tuv: { ...T; ...U; a: V; }) => { t: T; u: U; v: V; }
+>{ ...b, ...c, a: 12 } : { a: number; c: number; b: number; }
+>b : any
+>c : any
+>a : number
+>12 : 12
+
+// can only infer { t: {}, u: {}, v: {} }
+let i2 = infer2({ ...b, ...c, a: 12 });
+>i2 : { t: {}; u: {}; v: {}; }
+>infer2({ ...b, ...c, a: 12 }) : { t: {}; u: {}; v: {}; }
+>infer2 : <T, U, V>(utv: { ...U; a: V; ...T }) => { t: T; u: U; v: V; }
+>{ ...b, ...c, a: 12 } : { a: number; c: number; b: number; }
+>b : any
+>c : any
+>a : number
+>12 : 12
+
+// can only infer { t: {}, u: {}, v: {} }
+let i3 = generic(b, c, { a: 12 });
+>i3 : { t: {}; u: {}; v: {}; }
+>generic(b, c, { a: 12 }) : { t: {}; u: {}; v: {}; }
+>generic : <W, X, Y>(w: W, x: X, y: Y) => { t: {}; u: {}; v: {}; }
+>b : { b: number; }
+>c : { c: number; }
+>{ a: 12 } : { a: number; }
+>a : number
+>12 : 12
+

tests/baselines/reference/objectSpreadIntersection.js

@@ -0,0 +1,77 @@
+//// [objectSpreadIntersection.ts]
+function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T | U;
+    let uv: U & V;
+    let result = { ...tu, ...uv, id: 'foo' };
+    let assignable: { ...(T | U), ...(U & V), id: string } = result;
+}
+// concrete types work
+interface A1 { a: number }
+interface A2 { a: string }
+interface B1 { b: number }
+interface B2 { b: string }
+let a12: A1 & A2;
+let b12: B1 & B2;
+let result = { ...a12, ...b12 };
+let sn: number & string = result.a;
+sn = result.b;
+let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
+
+function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tuv: T & U & V;
+    let result = { ...tuv, id: 'bar' };
+    let assignable: { ...(T & U & V), id: string } = result;
+}
+function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T & U;
+    let uv: U & V;
+    let result = { ...tu, ...uv, id: 'baz' };
+    let assignable: { ...(T & U), ...(U & V), id: string } = result;
+}
+function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
+    let tu: T & U;
+    let uv: U | V;
+    let result = { ...tu, ...uv, id: 'qux' };
+    let assignable: { ...(T & U), ...(U | V), id: string } = result;
+}
+
+
+
+//// [objectSpreadIntersection.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+function iteratedUnionIntersection(t, u, v) {
+    var tu;
+    var uv;
+    var result = __assign({}, tu, uv, { id: 'foo' });
+    var assignable = result;
+}
+var a12;
+var b12;
+var result = __assign({}, a12, b12);
+var sn = result.a;
+sn = result.b;
+var assignable = result;
+function tripleIntersection(t, u, v) {
+    var tuv;
+    var result = __assign({}, tuv, { id: 'bar' });
+    var assignable = result;
+}
+function iteratedDoubleIntersection(t, u, v) {
+    var tu;
+    var uv;
+    var result = __assign({}, tu, uv, { id: 'baz' });
+    var assignable = result;
+}
+function iteratedIntersectionUnion(t, u, v) {
+    var tu;
+    var uv;
+    var result = __assign({}, tu, uv, { id: 'qux' });
+    var assignable = result;
+}

tests/baselines/reference/objectSpreadIntersection.symbols

@@ -0,0 +1,188 @@
+=== tests/cases/conformance/types/spread/objectSpreadIntersection.ts ===
+function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedUnionIntersection : Symbol(iteratedUnionIntersection, Decl(objectSpreadIntersection.ts, 0, 0))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 0, 44))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 0, 49))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 0, 55))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+
+    let tu: T | U;
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 1, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+
+    let uv: U & V;
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 2, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+
+    let result = { ...tu, ...uv, id: 'foo' };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 3, 32))
+
+    let assignable: { ...(T | U), ...(U & V), id: string } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 4, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 0, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 0, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 0, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 4, 45))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 3, 7))
+}
+// concrete types work
+interface A1 { a: number }
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
+>a : Symbol(A1.a, Decl(objectSpreadIntersection.ts, 7, 14))
+
+interface A2 { a: string }
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
+>a : Symbol(A2.a, Decl(objectSpreadIntersection.ts, 8, 14))
+
+interface B1 { b: number }
+>B1 : Symbol(B1, Decl(objectSpreadIntersection.ts, 8, 26))
+>b : Symbol(B1.b, Decl(objectSpreadIntersection.ts, 9, 14))
+
+interface B2 { b: string }
+>B2 : Symbol(B2, Decl(objectSpreadIntersection.ts, 9, 26))
+>b : Symbol(B2.b, Decl(objectSpreadIntersection.ts, 10, 14))
+
+let a12: A1 & A2;
+>a12 : Symbol(a12, Decl(objectSpreadIntersection.ts, 11, 3))
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
+
+let b12: B1 & B2;
+>b12 : Symbol(b12, Decl(objectSpreadIntersection.ts, 12, 3))
+>B1 : Symbol(B1, Decl(objectSpreadIntersection.ts, 8, 26))
+>B2 : Symbol(B2, Decl(objectSpreadIntersection.ts, 9, 26))
+
+let result = { ...a12, ...b12 };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
+
+let sn: number & string = result.a;
+>sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 14, 3))
+>result.a : Symbol(a, Decl(objectSpreadIntersection.ts, 7, 14), Decl(objectSpreadIntersection.ts, 8, 14))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
+>a : Symbol(a, Decl(objectSpreadIntersection.ts, 7, 14), Decl(objectSpreadIntersection.ts, 8, 14))
+
+sn = result.b;
+>sn : Symbol(sn, Decl(objectSpreadIntersection.ts, 14, 3))
+>result.b : Symbol(b, Decl(objectSpreadIntersection.ts, 9, 14), Decl(objectSpreadIntersection.ts, 10, 14))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
+>b : Symbol(b, Decl(objectSpreadIntersection.ts, 9, 14), Decl(objectSpreadIntersection.ts, 10, 14))
+
+let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 16, 3))
+>A1 : Symbol(A1, Decl(objectSpreadIntersection.ts, 5, 1))
+>A2 : Symbol(A2, Decl(objectSpreadIntersection.ts, 7, 26))
+>B1 : Symbol(B1, Decl(objectSpreadIntersection.ts, 8, 26))
+>B2 : Symbol(B2, Decl(objectSpreadIntersection.ts, 9, 26))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 13, 3))
+
+function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>tripleIntersection : Symbol(tripleIntersection, Decl(objectSpreadIntersection.ts, 16, 56))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 18, 37))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 18, 42))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 18, 48))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
+
+    let tuv: T & U & V;
+>tuv : Symbol(tuv, Decl(objectSpreadIntersection.ts, 19, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
+
+    let result = { ...tuv, id: 'bar' };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 20, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 20, 26))
+
+    let assignable: { ...(T & U & V), id: string } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 21, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 18, 28))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 18, 30))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 18, 33))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 21, 37))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 20, 7))
+}
+function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedDoubleIntersection : Symbol(iteratedDoubleIntersection, Decl(objectSpreadIntersection.ts, 22, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 23, 45))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 23, 50))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 23, 56))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
+
+    let tu: T & U;
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 24, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+
+    let uv: U & V;
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 25, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
+
+    let result = { ...tu, ...uv, id: 'baz' };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 26, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 26, 32))
+
+    let assignable: { ...(T & U), ...(U & V), id: string } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 27, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 23, 36))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 23, 38))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 23, 41))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 27, 45))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 26, 7))
+}
+function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
+>iteratedIntersectionUnion : Symbol(iteratedIntersectionUnion, Decl(objectSpreadIntersection.ts, 28, 1))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
+>t : Symbol(t, Decl(objectSpreadIntersection.ts, 29, 44))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>u : Symbol(u, Decl(objectSpreadIntersection.ts, 29, 49))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>v : Symbol(v, Decl(objectSpreadIntersection.ts, 29, 55))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
+
+    let tu: T & U;
+>tu : Symbol(tu, Decl(objectSpreadIntersection.ts, 30, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+
+    let uv: U | V;
+>uv : Symbol(uv, Decl(objectSpreadIntersection.ts, 31, 7))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
+
+    let result = { ...tu, ...uv, id: 'qux' };
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 32, 7))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 32, 32))
+
+    let assignable: { ...(T & U), ...(U | V), id: string } = result;
+>assignable : Symbol(assignable, Decl(objectSpreadIntersection.ts, 33, 7))
+>T : Symbol(T, Decl(objectSpreadIntersection.ts, 29, 35))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>U : Symbol(U, Decl(objectSpreadIntersection.ts, 29, 37))
+>V : Symbol(V, Decl(objectSpreadIntersection.ts, 29, 40))
+>id : Symbol(id, Decl(objectSpreadIntersection.ts, 33, 45))
+>result : Symbol(result, Decl(objectSpreadIntersection.ts, 32, 7))
+}
+
+

tests/baselines/reference/objectSpreadIntersection.types

@@ -0,0 +1,207 @@
+=== tests/cases/conformance/types/spread/objectSpreadIntersection.ts ===
+function iteratedUnionIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedUnionIntersection : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tu: T | U;
+>tu : T | U
+>T : T
+>U : U
+
+    let uv: U & V;
+>uv : U & V
+>U : U
+>V : V
+
+    let result = { ...tu, ...uv, id: 'foo' };
+>result : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
+>{ ...tu, ...uv, id: 'foo' } : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
+>tu : any
+>uv : any
+>id : string
+>'foo' : "foo"
+
+    let assignable: { ...(T | U), ...(U & V), id: string } = result;
+>assignable : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
+>T : T
+>U : U
+>U : U
+>V : V
+>id : string
+>result : { ...T; ...U & V; id: string; } | { ...U; ...U & V; id: string; }
+}
+// concrete types work
+interface A1 { a: number }
+>A1 : A1
+>a : number
+
+interface A2 { a: string }
+>A2 : A2
+>a : string
+
+interface B1 { b: number }
+>B1 : B1
+>b : number
+
+interface B2 { b: string }
+>B2 : B2
+>b : string
+
+let a12: A1 & A2;
+>a12 : A1 & A2
+>A1 : A1
+>A2 : A2
+
+let b12: B1 & B2;
+>b12 : B1 & B2
+>B1 : B1
+>B2 : B2
+
+let result = { ...a12, ...b12 };
+>result : { b: number & string; a: number & string; }
+>{ ...a12, ...b12 } : { b: number & string; a: number & string; }
+>a12 : any
+>b12 : any
+
+let sn: number & string = result.a;
+>sn : number & string
+>result.a : number & string
+>result : { b: number & string; a: number & string; }
+>a : number & string
+
+sn = result.b;
+>sn = result.b : number & string
+>sn : number & string
+>result.b : number & string
+>result : { b: number & string; a: number & string; }
+>b : number & string
+
+let assignable: { ...(A1 & A2), ...(B1 & B2) } = result;
+>assignable : { b: number & string; a: number & string; }
+>A1 : A1
+>A2 : A2
+>B1 : B1
+>B2 : B2
+>result : { b: number & string; a: number & string; }
+
+function tripleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>tripleIntersection : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tuv: T & U & V;
+>tuv : T & U & V
+>T : T
+>U : U
+>V : V
+
+    let result = { ...tuv, id: 'bar' };
+>result : { ...T & U & V; id: string; }
+>{ ...tuv, id: 'bar' } : { ...T & U & V; id: string; }
+>tuv : any
+>id : string
+>'bar' : "bar"
+
+    let assignable: { ...(T & U & V), id: string } = result;
+>assignable : { ...T & U & V; id: string; }
+>T : T
+>U : U
+>V : V
+>id : string
+>result : { ...T & U & V; id: string; }
+}
+function iteratedDoubleIntersection<T, U, V>(t: T, u: U, v: V): void {
+>iteratedDoubleIntersection : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tu: T & U;
+>tu : T & U
+>T : T
+>U : U
+
+    let uv: U & V;
+>uv : U & V
+>U : U
+>V : V
+
+    let result = { ...tu, ...uv, id: 'baz' };
+>result : { ...T & U; ...U & V; id: string; }
+>{ ...tu, ...uv, id: 'baz' } : { ...T & U; ...U & V; id: string; }
+>tu : any
+>uv : any
+>id : string
+>'baz' : "baz"
+
+    let assignable: { ...(T & U), ...(U & V), id: string } = result;
+>assignable : { ...T & U; ...U & V; id: string; }
+>T : T
+>U : U
+>U : U
+>V : V
+>id : string
+>result : { ...T & U; ...U & V; id: string; }
+}
+function iteratedIntersectionUnion<T, U, V>(t: T, u: U, v: V): void {
+>iteratedIntersectionUnion : <T, U, V>(t: T, u: U, v: V) => void
+>T : T
+>U : U
+>V : V
+>t : T
+>T : T
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let tu: T & U;
+>tu : T & U
+>T : T
+>U : U
+
+    let uv: U | V;
+>uv : U | V
+>U : U
+>V : V
+
+    let result = { ...tu, ...uv, id: 'qux' };
+>result : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
+>{ ...tu, ...uv, id: 'qux' } : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
+>tu : any
+>uv : any
+>id : string
+>'qux' : "qux"
+
+    let assignable: { ...(T & U), ...(U | V), id: string } = result;
+>assignable : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
+>T : T
+>U : U
+>U : U
+>V : V
+>id : string
+>result : { ...T & U; ...U; id: string; } | { ...T & U; ...V; id: string; }
+}
+
+