diff --git a/issue_template.md b/issue_template.md
new file mode 100644
index 00000000000..dcd2280570c
--- /dev/null
+++ b/issue_template.md
@@ -0,0 +1,27 @@
+<!--
+Thank you for contributing to TypeScript! Please review this checklist
+       before submitting your issue.
+[ ] Many common issues and suggestions are addressed in the FAQ
+     https://github.com/Microsoft/TypeScript/wiki/FAQ
+[ ] Search for duplicates before logging new issues
+    https://github.com/Microsoft/TypeScript/issues?utf8=%E2%9C%93&q=is%3Aissue
+[ ] Questions are best asked and answered at Stack Overflow
+    http://stackoverflow.com/questions/tagged/typescript
+
+For bug reports, please include the information below.
+__________________________________________________________ -->
+
+**TypeScript Version:** 
+
+1.7.5 / 1.8.0-beta / nightly (1.9.0-dev.20160217)
+
+**Code**
+
+```ts
+// A self-contained demonstration of the problem follows...
+
+```
+
+**Expected behavior:**
+
+**Actual behavior:** 
diff --git a/pull_request_template.md b/pull_request_template.md
new file mode 100644
index 00000000000..2baaa3521dd
--- /dev/null
+++ b/pull_request_template.md
@@ -0,0 +1,16 @@
+<!--
+Thank you for submitting a pull request!
+
+Here's a checklist you might find useful.
+[ ] There is an associated issue that is labelled
+  'Bug' or 'Accepting PRs' or is in the Community milestone
+[ ] Code is up-to-date with the `master` branch
+[ ] You've successfully run `jake runtests` locally
+[ ] You've signed the CLA
+[ ] There are new or updated unit tests validating the change
+
+Refer to CONTRIBUTING.MD for more details.
+  https://github.com/Microsoft/TypeScript/blob/master/CONTRIBUTING.md
+-->
+
+**Fixes issue:** #
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 6a95162804a..7000ace8aff 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -133,8 +133,8 @@ namespace ts {
 
         const noConstraintType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
 
-        const anySignature = createSignature(undefined, undefined, emptyArray, anyType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
-        const unknownSignature = createSignature(undefined, undefined, emptyArray, unknownType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
+        const anySignature = createSignature(undefined, undefined, emptyArray, anyType, /*typePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
+        const unknownSignature = createSignature(undefined, undefined, emptyArray, unknownType, /*typePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
 
         const enumNumberIndexInfo = createIndexInfo(stringType, /*isReadonly*/ true);
 
@@ -1713,6 +1713,25 @@ namespace ts {
             return result;
         }
 
+        function typePredicateToString(typePredicate: TypePredicate, enclosingDeclaration?: Declaration, flags?: TypeFormatFlags): string {
+            const writer = getSingleLineStringWriter();
+            getSymbolDisplayBuilder().buildTypePredicateDisplay(typePredicate, writer, enclosingDeclaration, flags);
+            const result = writer.string();
+            releaseStringWriter(writer);
+
+            return result;
+        }
+
+        function visibilityToString(flags: NodeFlags) {
+            if (flags === NodeFlags.Private) {
+                return "private";
+            }
+            if (flags === NodeFlags.Protected) {
+                return "protected";
+            }
+            return "public";
+        }
+
         function getTypeAliasForTypeLiteral(type: Type): Symbol {
             if (type.symbol && type.symbol.flags & SymbolFlags.TypeLiteral) {
                 let node = type.symbol.declarations[0].parent;
@@ -1846,16 +1865,10 @@ namespace ts {
                 function writeType(type: Type, flags: TypeFormatFlags) {
                     // Write undefined/null type as any
                     if (type.flags & TypeFlags.Intrinsic) {
-                        if (type.flags & TypeFlags.PredicateType) {
-                            buildTypePredicateDisplay(writer, (type as PredicateType).predicate);
-                            buildTypeDisplay((type as PredicateType).predicate.type, writer, enclosingDeclaration, flags, symbolStack);
-                        }
-                        else {
-                            // Special handling for unknown / resolving types, they should show up as any and not unknown or __resolving
-                            writer.writeKeyword(!(globalFlags & TypeFormatFlags.WriteOwnNameForAnyLike) && isTypeAny(type)
-                                ? "any"
-                                : (<IntrinsicType>type).intrinsicName);
-                        }
+                        // Special handling for unknown / resolving types, they should show up as any and not unknown or __resolving
+                        writer.writeKeyword(!(globalFlags & TypeFormatFlags.WriteOwnNameForAnyLike) && isTypeAny(type)
+                            ? "any"
+                            : (<IntrinsicType>type).intrinsicName);
                     }
                     else if (type.flags & TypeFlags.ThisType) {
                         if (inObjectTypeLiteral) {
@@ -2219,7 +2232,7 @@ namespace ts {
                 writePunctuation(writer, SyntaxKind.CloseParenToken);
             }
 
-            function buildTypePredicateDisplay(writer: SymbolWriter, predicate: TypePredicate) {
+            function buildTypePredicateDisplay(predicate: TypePredicate, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, symbolStack?: Symbol[]): void {
                 if (isIdentifierTypePredicate(predicate)) {
                     writer.writeParameter(predicate.parameterName);
                 }
@@ -2229,6 +2242,7 @@ namespace ts {
                 writeSpace(writer);
                 writeKeyword(writer, SyntaxKind.IsKeyword);
                 writeSpace(writer);
+                buildTypeDisplay(predicate.type, writer, enclosingDeclaration, flags, symbolStack);
             }
 
             function buildReturnTypeDisplay(signature: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, symbolStack?: Symbol[]) {
@@ -2241,8 +2255,13 @@ namespace ts {
                 }
                 writeSpace(writer);
 
-                const returnType = getReturnTypeOfSignature(signature);
-                buildTypeDisplay(returnType, writer, enclosingDeclaration, flags, symbolStack);
+                if (signature.typePredicate) {
+                    buildTypePredicateDisplay(signature.typePredicate, writer, enclosingDeclaration, flags, symbolStack);
+                }
+                else {
+                    const returnType = getReturnTypeOfSignature(signature);
+                    buildTypeDisplay(returnType, writer, enclosingDeclaration, flags, symbolStack);
+                }
             }
 
             function buildSignatureDisplay(signature: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind, symbolStack?: Symbol[]) {
@@ -2261,6 +2280,7 @@ namespace ts {
                 }
 
                 buildDisplayForParametersAndDelimiters(signature.parameters, writer, enclosingDeclaration, flags, symbolStack);
+
                 buildReturnTypeDisplay(signature, writer, enclosingDeclaration, flags, symbolStack);
             }
 
@@ -2268,6 +2288,7 @@ namespace ts {
                 buildSymbolDisplay,
                 buildTypeDisplay,
                 buildTypeParameterDisplay,
+                buildTypePredicateDisplay,
                 buildParameterDisplay,
                 buildDisplayForParametersAndDelimiters,
                 buildDisplayForTypeParametersAndDelimiters,
@@ -2808,9 +2829,6 @@ namespace ts {
                 if (declaration.kind === SyntaxKind.PropertyAssignment) {
                     return type;
                 }
-                if (type.flags & TypeFlags.PredicateType && (declaration.kind === SyntaxKind.PropertyDeclaration || declaration.kind === SyntaxKind.PropertySignature)) {
-                    return type;
-                }
                 return getWidenedType(type);
             }
 
@@ -3541,12 +3559,13 @@ namespace ts {
         }
 
         function createSignature(declaration: SignatureDeclaration, typeParameters: TypeParameter[], parameters: Symbol[],
-            resolvedReturnType: Type, minArgumentCount: number, hasRestParameter: boolean, hasStringLiterals: boolean): Signature {
+            resolvedReturnType: Type, typePredicate: TypePredicate, minArgumentCount: number, hasRestParameter: boolean, hasStringLiterals: boolean): Signature {
             const sig = new Signature(checker);
             sig.declaration = declaration;
             sig.typeParameters = typeParameters;
             sig.parameters = parameters;
             sig.resolvedReturnType = resolvedReturnType;
+            sig.typePredicate = typePredicate;
             sig.minArgumentCount = minArgumentCount;
             sig.hasRestParameter = hasRestParameter;
             sig.hasStringLiterals = hasStringLiterals;
@@ -3555,14 +3574,14 @@ namespace ts {
 
         function cloneSignature(sig: Signature): Signature {
             return createSignature(sig.declaration, sig.typeParameters, sig.parameters, sig.resolvedReturnType,
-                sig.minArgumentCount, sig.hasRestParameter, sig.hasStringLiterals);
+                sig.typePredicate, sig.minArgumentCount, sig.hasRestParameter, sig.hasStringLiterals);
         }
 
         function getDefaultConstructSignatures(classType: InterfaceType): Signature[] {
             const baseConstructorType = getBaseConstructorTypeOfClass(classType);
             const baseSignatures = getSignaturesOfType(baseConstructorType, SignatureKind.Construct);
             if (baseSignatures.length === 0) {
-                return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false)];
+                return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, /*typePredicate*/ undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false)];
             }
             const baseTypeNode = getBaseTypeNodeOfClass(classType);
             const typeArguments = map(baseTypeNode.typeArguments, getTypeFromTypeNode);
@@ -3995,6 +4014,19 @@ namespace ts {
             return getIndexTypeOfStructuredType(getApparentType(type), kind);
         }
 
+        function getImplicitIndexTypeOfType(type: Type, kind: IndexKind): Type {
+            if (isObjectLiteralType(type)) {
+                const propTypes: Type[] = [];
+                for (const prop of getPropertiesOfType(type)) {
+                    if (kind === IndexKind.String || isNumericLiteralName(prop.name)) {
+                        propTypes.push(getTypeOfSymbol(prop));
+                    }
+                }
+                return getUnionType(propTypes);
+            }
+            return undefined;
+        }
+
         function getTypeParametersFromJSDocTemplate(declaration: SignatureDeclaration): TypeParameter[] {
             if (declaration.flags & NodeFlags.JavaScriptFile) {
                 const templateTag = getJSDocTemplateTag(declaration);
@@ -4094,6 +4126,7 @@ namespace ts {
                 let minArgumentCount = -1;
                 const isJSConstructSignature = isJSDocConstructSignature(declaration);
                 let returnType: Type = undefined;
+                let typePredicate: TypePredicate = undefined;
 
                 // If this is a JSDoc construct signature, then skip the first parameter in the
                 // parameter list.  The first parameter represents the return type of the construct
@@ -4137,6 +4170,9 @@ namespace ts {
                 }
                 else if (declaration.type) {
                     returnType = getTypeFromTypeNode(declaration.type);
+                    if (declaration.type.kind === SyntaxKind.TypePredicate) {
+                        typePredicate = createTypePredicateFromTypePredicateNode(declaration.type as TypePredicateNode);
+                    }
                 }
                 else {
                     if (declaration.flags & NodeFlags.JavaScriptFile) {
@@ -4158,7 +4194,7 @@ namespace ts {
                     }
                 }
 
-                links.resolvedSignature = createSignature(declaration, typeParameters, parameters, returnType, minArgumentCount, hasRestParameter(declaration), hasStringLiterals);
+                links.resolvedSignature = createSignature(declaration, typeParameters, parameters, returnType, typePredicate, minArgumentCount, hasRestParameter(declaration), hasStringLiterals);
             }
             return links.resolvedSignature;
         }
@@ -4886,25 +4922,6 @@ namespace ts {
             return links.resolvedType;
         }
 
-        function getPredicateType(node: TypePredicateNode): Type {
-            return createPredicateType(getSymbolOfNode(node), createTypePredicateFromTypePredicateNode(node));
-        }
-
-        function createPredicateType(symbol: Symbol, predicate: ThisTypePredicate | IdentifierTypePredicate) {
-                const type = createType(TypeFlags.Boolean | TypeFlags.PredicateType) as PredicateType;
-                type.symbol = symbol;
-                type.predicate = predicate;
-                return type;
-        }
-
-        function getTypeFromPredicateTypeNode(node: TypePredicateNode): Type {
-            const links = getNodeLinks(node);
-            if (!links.resolvedType) {
-                links.resolvedType = getPredicateType(node);
-            }
-            return links.resolvedType;
-        }
-
         function getTypeFromTypeNode(node: TypeNode): Type {
             switch (node.kind) {
                 case SyntaxKind.AnyKeyword:
@@ -4929,7 +4946,7 @@ namespace ts {
                 case SyntaxKind.JSDocTypeReference:
                     return getTypeFromTypeReference(<TypeReferenceNode>node);
                 case SyntaxKind.TypePredicate:
-                    return getTypeFromPredicateTypeNode(<TypePredicateNode>node);
+                    return booleanType;
                 case SyntaxKind.ExpressionWithTypeArguments:
                     return getTypeFromTypeReference(<ExpressionWithTypeArguments>node);
                 case SyntaxKind.TypeQuery:
@@ -5083,6 +5100,7 @@ namespace ts {
 
         function instantiateSignature(signature: Signature, mapper: TypeMapper, eraseTypeParameters?: boolean): Signature {
             let freshTypeParameters: TypeParameter[];
+            let freshTypePredicate: TypePredicate;
             if (signature.typeParameters && !eraseTypeParameters) {
                 // First create a fresh set of type parameters, then include a mapping from the old to the
                 // new type parameters in the mapper function. Finally store this mapper in the new type
@@ -5093,9 +5111,13 @@ namespace ts {
                     tp.mapper = mapper;
                 }
             }
+            if (signature.typePredicate) {
+                freshTypePredicate = cloneTypePredicate(signature.typePredicate, mapper);
+            }
             const result = createSignature(signature.declaration, freshTypeParameters,
                 instantiateList(signature.parameters, mapper, instantiateSymbol),
                 instantiateType(signature.resolvedReturnType, mapper),
+                freshTypePredicate,
                 signature.minArgumentCount, signature.hasRestParameter, signature.hasStringLiterals);
             result.target = signature;
             result.mapper = mapper;
@@ -5165,10 +5187,6 @@ namespace ts {
                 if (type.flags & TypeFlags.Intersection) {
                     return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType));
                 }
-                if (type.flags & TypeFlags.PredicateType) {
-                    const predicate = (type as PredicateType).predicate;
-                    return createPredicateType(type.symbol, cloneTypePredicate(predicate, mapper));
-                }
             }
             return type;
         }
@@ -5314,21 +5332,58 @@ namespace ts {
                 const sourceReturnType = getReturnTypeOfSignature(source);
 
                 // The following block preserves behavior forbidding boolean returning functions from being assignable to type guard returning functions
-                if (targetReturnType.flags & TypeFlags.PredicateType && (targetReturnType as PredicateType).predicate.kind === TypePredicateKind.Identifier) {
-                    if (!(sourceReturnType.flags & TypeFlags.PredicateType)) {
+                if (target.typePredicate) {
+                    if (source.typePredicate) {
+                        result &= compareTypePredicateRelatedTo(source.typePredicate, target.typePredicate, reportErrors, errorReporter, compareTypes);
+                    }
+                    else if (isIdentifierTypePredicate(target.typePredicate)) {
                         if (reportErrors) {
                             errorReporter(Diagnostics.Signature_0_must_have_a_type_predicate, signatureToString(source));
                         }
                         return Ternary.False;
                     }
                 }
+                else {
+                    result &= compareTypes(sourceReturnType, targetReturnType, reportErrors);
+                }
 
-                result &= compareTypes(sourceReturnType, targetReturnType, reportErrors);
             }
 
             return result;
         }
 
+        function compareTypePredicateRelatedTo(source: TypePredicate,
+                                               target: TypePredicate,
+                                               reportErrors: boolean,
+                                               errorReporter: (d: DiagnosticMessage, arg0?: string, arg1?: string) => void,
+                                               compareTypes: (s: Type, t: Type, reportErrors?: boolean) => Ternary): Ternary {
+            if (source.kind !== target.kind) {
+                if (reportErrors) {
+                    errorReporter(Diagnostics.A_this_based_type_guard_is_not_compatible_with_a_parameter_based_type_guard);
+                    errorReporter(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typePredicateToString(source), typePredicateToString(target));
+                }
+                return Ternary.False;
+            }
+
+            if (source.kind === TypePredicateKind.Identifier) {
+                const sourceIdentifierPredicate = source as IdentifierTypePredicate;
+                const targetIdentifierPredicate = target as IdentifierTypePredicate;
+                if (sourceIdentifierPredicate.parameterIndex !== targetIdentifierPredicate.parameterIndex) {
+                    if (reportErrors) {
+                        errorReporter(Diagnostics.Parameter_0_is_not_in_the_same_position_as_parameter_1, sourceIdentifierPredicate.parameterName, targetIdentifierPredicate.parameterName);
+                        errorReporter(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typePredicateToString(source), typePredicateToString(target));
+                    }
+                    return Ternary.False;
+                }
+            }
+
+            const related = compareTypes(source.type, target.type, reportErrors);
+            if (related === Ternary.False && reportErrors) {
+                errorReporter(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typePredicateToString(source), typePredicateToString(target));
+            }
+            return related;
+        }
+
         function isImplementationCompatibleWithOverload(implementation: Signature, overload: Signature): boolean {
             const erasedSource = getErasedSignature(implementation);
             const erasedTarget = getErasedSignature(overload);
@@ -5456,33 +5511,6 @@ namespace ts {
                     if (source === numberType && target.flags & TypeFlags.Enum) return Ternary.True;
                 }
                 if (source.flags & TypeFlags.Boolean && target.flags & TypeFlags.Boolean) {
-                    if (source.flags & TypeFlags.PredicateType && target.flags & TypeFlags.PredicateType) {
-                        const sourcePredicate = source as PredicateType;
-                        const targetPredicate = target as PredicateType;
-                        if (sourcePredicate.predicate.kind !== targetPredicate.predicate.kind) {
-                            if (reportErrors) {
-                                reportError(Diagnostics.A_this_based_type_guard_is_not_compatible_with_a_parameter_based_type_guard);
-                                reportError(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typeToString(source), typeToString(target));
-                            }
-                            return Ternary.False;
-                        }
-                        if (sourcePredicate.predicate.kind === TypePredicateKind.Identifier) {
-                            const sourceIdentifierPredicate = sourcePredicate.predicate as IdentifierTypePredicate;
-                            const targetIdentifierPredicate = targetPredicate.predicate as IdentifierTypePredicate;
-                            if (sourceIdentifierPredicate.parameterIndex !== targetIdentifierPredicate.parameterIndex) {
-                                if (reportErrors) {
-                                    reportError(Diagnostics.Parameter_0_is_not_in_the_same_position_as_parameter_1, sourceIdentifierPredicate.parameterName, targetIdentifierPredicate.parameterName);
-                                    reportError(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typeToString(source), typeToString(target));
-                                }
-                                return Ternary.False;
-                            }
-                        }
-                        const related = isRelatedTo(sourcePredicate.predicate.type, targetPredicate.predicate.type, reportErrors, headMessage);
-                        if (related === Ternary.False && reportErrors) {
-                            reportError(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typeToString(source), typeToString(target));
-                        }
-                        return related;
-                    }
                     return Ternary.True;
                 }
 
@@ -5774,9 +5802,9 @@ namespace ts {
                         if (result) {
                             result &= signaturesRelatedTo(source, target, SignatureKind.Construct, reportErrors);
                             if (result) {
-                                result &= stringIndexTypesRelatedTo(source, originalSource, target, reportErrors);
+                                result &= indexTypesRelatedTo(source, originalSource, target, IndexKind.String, reportErrors);
                                 if (result) {
-                                    result &= numberIndexTypesRelatedTo(source, originalSource, target, reportErrors);
+                                    result &= indexTypesRelatedTo(source, originalSource, target, IndexKind.Number, reportErrors);
                                 }
                             }
                         }
@@ -5916,16 +5944,20 @@ namespace ts {
 
                 const sourceSignatures = getSignaturesOfType(source, kind);
                 const targetSignatures = getSignaturesOfType(target, kind);
-                if (kind === SignatureKind.Construct && sourceSignatures.length && targetSignatures.length &&
-                    isAbstractConstructorType(source) && !isAbstractConstructorType(target)) {
-                    // An abstract constructor type is not assignable to a non-abstract constructor type
+                if (kind === SignatureKind.Construct && sourceSignatures.length && targetSignatures.length) {
+                    if (isAbstractConstructorType(source) && !isAbstractConstructorType(target)) {
+                        // An abstract constructor type is not assignable to a non-abstract constructor type
                     // as it would otherwise be possible to new an abstract class. Note that the assignability
-                    // check we perform for an extends clause excludes construct signatures from the target,
-                    // so this check never proceeds.
-                    if (reportErrors) {
-                        reportError(Diagnostics.Cannot_assign_an_abstract_constructor_type_to_a_non_abstract_constructor_type);
+                        // check we perform for an extends clause excludes construct signatures from the target,
+                        // so this check never proceeds.
+                        if (reportErrors) {
+                            reportError(Diagnostics.Cannot_assign_an_abstract_constructor_type_to_a_non_abstract_constructor_type);
+                        }
+                        return Ternary.False;
+                    }
+                    if (!constructorVisibilitiesAreCompatible(sourceSignatures[0], targetSignatures[0], reportErrors)) {
+                        return Ternary.False;
                     }
-                    return Ternary.False;
                 }
 
                 let result = Ternary.True;
@@ -5978,76 +6010,65 @@ namespace ts {
                 return result;
             }
 
-            function stringIndexTypesRelatedTo(source: Type, originalSource: Type, target: Type, reportErrors: boolean): Ternary {
-                if (relation === identityRelation) {
-                    return indexTypesIdenticalTo(IndexKind.String, source, target);
+            function eachPropertyRelatedTo(source: Type, target: Type, kind: IndexKind, reportErrors: boolean): Ternary {
+                let result = Ternary.True;
+                for (const prop of getPropertiesOfObjectType(source)) {
+                    if (kind === IndexKind.String || isNumericLiteralName(prop.name)) {
+                        const related = isRelatedTo(getTypeOfSymbol(prop), target, reportErrors);
+                        if (!related) {
+                            if (reportErrors) {
+                                reportError(Diagnostics.Property_0_is_incompatible_with_index_signature, symbolToString(prop));
+                            }
+                            return Ternary.False;
+                        }
+                        result &= related;
+                    }
                 }
-                const targetInfo = getIndexInfoOfType(target, IndexKind.String);
-                if (targetInfo) {
-                    if ((targetInfo.type.flags & TypeFlags.Any) && !(originalSource.flags & TypeFlags.Primitive)) {
-                        // non-primitive assignment to any is always allowed, eg
-                        //   `var x: { [index: string]: any } = { property: 12 };`
-                        return Ternary.True;
-                    }
-                    const sourceInfo = getIndexInfoOfType(source, IndexKind.String);
-                    if (!sourceInfo) {
-                        if (reportErrors) {
-                            reportError(Diagnostics.Index_signature_is_missing_in_type_0, typeToString(source));
+                return result;
+            }
+
+            function indexInfoRelatedTo(sourceInfo: IndexInfo, targetInfo: IndexInfo, reportErrors: boolean) {
+                const related = isRelatedTo(sourceInfo.type, targetInfo.type, reportErrors);
+                if (!related && reportErrors) {
+                    reportError(Diagnostics.Index_signatures_are_incompatible);
+                }
+                return related;
+            }
+
+            function indexTypesRelatedTo(source: Type, originalSource: Type, target: Type, kind: IndexKind, reportErrors: boolean) {
+                if (relation === identityRelation) {
+                    return indexTypesIdenticalTo(source, target, kind);
+                }
+                const targetInfo = getIndexInfoOfType(target, kind);
+                if (!targetInfo || ((targetInfo.type.flags & TypeFlags.Any) && !(originalSource.flags & TypeFlags.Primitive))) {
+                    // Index signature of type any permits assignment from everything but primitives
+                    return Ternary.True;
+                }
+                const sourceInfo = getIndexInfoOfType(source, kind) ||
+                    kind === IndexKind.Number && getIndexInfoOfType(source, IndexKind.String);
+                if (sourceInfo) {
+                    return indexInfoRelatedTo(sourceInfo, targetInfo, reportErrors);
+                }
+                if (isObjectLiteralType(source)) {
+                    let related = Ternary.True;
+                    if (kind === IndexKind.String) {
+                        const sourceNumberInfo = getIndexInfoOfType(source, IndexKind.Number);
+                        if (sourceNumberInfo) {
+                            related = indexInfoRelatedTo(sourceNumberInfo, targetInfo, reportErrors);
                         }
-                        return Ternary.False;
                     }
-                    const related = isRelatedTo(sourceInfo.type, targetInfo.type, reportErrors);
-                    if (!related) {
-                        if (reportErrors) {
-                            reportError(Diagnostics.Index_signatures_are_incompatible);
-                        }
-                        return Ternary.False;
+                    if (related) {
+                        related &= eachPropertyRelatedTo(source, targetInfo.type, kind, reportErrors);
                     }
                     return related;
                 }
-                return Ternary.True;
+                if (reportErrors) {
+                    reportError(Diagnostics.Index_signature_is_missing_in_type_0, typeToString(source));
+                }
+                return Ternary.False;
             }
 
-            function numberIndexTypesRelatedTo(source: Type, originalSource: Type, target: Type, reportErrors: boolean): Ternary {
-                if (relation === identityRelation) {
-                    return indexTypesIdenticalTo(IndexKind.Number, source, target);
-                }
-                const targetInfo = getIndexInfoOfType(target, IndexKind.Number);
-                if (targetInfo) {
-                    if ((targetInfo.type.flags & TypeFlags.Any) && !(originalSource.flags & TypeFlags.Primitive)) {
-                        // non-primitive assignment to any is always allowed, eg
-                        //   `var x: { [index: number]: any } = { property: 12 };`
-                        return Ternary.True;
-                    }
-                    const sourceStringInfo = getIndexInfoOfType(source, IndexKind.String);
-                    const sourceNumberInfo = getIndexInfoOfType(source, IndexKind.Number);
-                    if (!(sourceStringInfo || sourceNumberInfo)) {
-                        if (reportErrors) {
-                            reportError(Diagnostics.Index_signature_is_missing_in_type_0, typeToString(source));
-                        }
-                        return Ternary.False;
-                    }
-                    let related: Ternary;
-                    if (sourceStringInfo && sourceNumberInfo) {
-                        // If we know for sure we're testing both string and numeric index types then only report errors from the second one
-                        related = isRelatedTo(sourceStringInfo.type, targetInfo.type, /*reportErrors*/ false) ||
-                            isRelatedTo(sourceNumberInfo.type, targetInfo.type, reportErrors);
-                    }
-                    else {
-                        related = isRelatedTo((sourceStringInfo || sourceNumberInfo).type, targetInfo.type, reportErrors);
-                    }
-                    if (!related) {
-                        if (reportErrors) {
-                            reportError(Diagnostics.Index_signatures_are_incompatible);
-                        }
-                        return Ternary.False;
-                    }
-                    return related;
-                }
-                return Ternary.True;
-            }
-
-            function indexTypesIdenticalTo(indexKind: IndexKind, source: Type, target: Type): Ternary {
+            function indexTypesIdenticalTo(source: Type, target: Type, indexKind: IndexKind): Ternary {
                 const targetInfo = getIndexInfoOfType(target, indexKind);
                 const sourceInfo = getIndexInfoOfType(source, indexKind);
                 if (!sourceInfo && !targetInfo) {
@@ -6079,6 +6100,36 @@ namespace ts {
                 }
                 return Ternary.True;
             }
+
+            function constructorVisibilitiesAreCompatible(sourceSignature: Signature, targetSignature: Signature, reportErrors: boolean) {
+                if (!sourceSignature.declaration || !targetSignature.declaration) {
+                    return true;
+                }
+
+                const sourceAccessibility = sourceSignature.declaration.flags & (NodeFlags.Private | NodeFlags.Protected);
+                const targetAccessibility = targetSignature.declaration.flags & (NodeFlags.Private | NodeFlags.Protected);
+
+                // A public, protected and private signature is assignable to a private signature.
+                if (targetAccessibility === NodeFlags.Private) {
+                    return true;
+                }
+
+                // A public and protected signature is assignable to a protected signature.
+                if (targetAccessibility === NodeFlags.Protected && sourceAccessibility !== NodeFlags.Private) {
+                    return true;
+                }
+
+                // Only a public signature is assignable to public signature.
+                if (targetAccessibility !== NodeFlags.Protected && !sourceAccessibility) {
+                    return true;
+                }
+
+                if (reportErrors) {
+                    reportError(Diagnostics.Cannot_assign_a_0_constructor_type_to_a_1_constructor_type, visibilityToString(sourceAccessibility), visibilityToString(targetAccessibility));
+                }
+
+                return false;
+            }
         }
 
         // Return true if the given type is the constructor type for an abstract class
@@ -6325,6 +6376,16 @@ namespace ts {
             return strictNullChecks && type.flags & TypeFlags.Union ? getNonNullableTypeFromUnionType(type as UnionType) : type;
         }
 
+        /**
+         * Return true if type was inferred from an object literal or written as an object type literal
+         * with no call or construct signatures.
+         */
+        function isObjectLiteralType(type: Type) {
+            return type.symbol && (type.symbol.flags & (SymbolFlags.ObjectLiteral | SymbolFlags.TypeLiteral)) !== 0 &&
+                getSignaturesOfType(type, SignatureKind.Call).length === 0 &&
+                getSignaturesOfType(type, SignatureKind.Construct).length === 0;
+        }
+
         function getRegularTypeOfObjectLiteral(type: Type): Type {
             if (type.flags & TypeFlags.FreshObjectLiteral) {
                 let regularType = (<FreshObjectLiteralType>type).regularType;
@@ -6377,9 +6438,6 @@ namespace ts {
                 if (type.flags & TypeFlags.Undefined) {
                     return anyType;
                 }
-                if (type.flags & TypeFlags.PredicateType) {
-                    return booleanType;
-                }
                 if (type.flags & TypeFlags.ObjectLiteral) {
                     return getWidenedTypeOfObjectLiteral(type);
                 }
@@ -6607,11 +6665,6 @@ namespace ts {
                         inferFromTypes(sourceTypes[i], targetTypes[i]);
                     }
                 }
-                else if (source.flags & TypeFlags.PredicateType && target.flags & TypeFlags.PredicateType) {
-                    if ((source as PredicateType).predicate.kind === (target as PredicateType).predicate.kind) {
-                        inferFromTypes((source as PredicateType).predicate.type, (target as PredicateType).predicate.type);
-                    }
-                }
                 else if (source.flags & TypeFlags.Tuple && target.flags & TypeFlags.Tuple && (<TupleType>source).elementTypes.length === (<TupleType>target).elementTypes.length) {
                     // If source and target are tuples of the same size, infer from element types
                     const sourceTypes = (<TupleType>source).elementTypes;
@@ -6676,9 +6729,7 @@ namespace ts {
                         inferFromProperties(source, target);
                         inferFromSignatures(source, target, SignatureKind.Call);
                         inferFromSignatures(source, target, SignatureKind.Construct);
-                        inferFromIndexTypes(source, target, IndexKind.String, IndexKind.String);
-                        inferFromIndexTypes(source, target, IndexKind.Number, IndexKind.Number);
-                        inferFromIndexTypes(source, target, IndexKind.String, IndexKind.Number);
+                        inferFromIndexTypes(source, target);
                         depth--;
                     }
                 }
@@ -6707,15 +6758,31 @@ namespace ts {
 
             function inferFromSignature(source: Signature, target: Signature) {
                 forEachMatchingParameterType(source, target, inferFromTypes);
-                inferFromTypes(getReturnTypeOfSignature(source), getReturnTypeOfSignature(target));
+
+                if (source.typePredicate && target.typePredicate && source.typePredicate.kind === target.typePredicate.kind) {
+                    inferFromTypes(source.typePredicate.type, target.typePredicate.type);
+                }
+                else {
+                    inferFromTypes(getReturnTypeOfSignature(source), getReturnTypeOfSignature(target));
+                }
             }
 
-            function inferFromIndexTypes(source: Type, target: Type, sourceKind: IndexKind, targetKind: IndexKind) {
-                const targetIndexType = getIndexTypeOfType(target, targetKind);
-                if (targetIndexType) {
-                    const sourceIndexType = getIndexTypeOfType(source, sourceKind);
+            function inferFromIndexTypes(source: Type, target: Type) {
+                const targetStringIndexType = getIndexTypeOfType(target, IndexKind.String);
+                if (targetStringIndexType) {
+                    const sourceIndexType = getIndexTypeOfType(source, IndexKind.String) ||
+                        getImplicitIndexTypeOfType(source, IndexKind.String);
                     if (sourceIndexType) {
-                        inferFromTypes(sourceIndexType, targetIndexType);
+                        inferFromTypes(sourceIndexType, targetStringIndexType);
+                    }
+                }
+                const targetNumberIndexType = getIndexTypeOfType(target, IndexKind.Number);
+                if (targetNumberIndexType) {
+                    const sourceIndexType = getIndexTypeOfType(source, IndexKind.Number) ||
+                        getIndexTypeOfType(source, IndexKind.String) ||
+                        getImplicitIndexTypeOfType(source, IndexKind.Number);
+                    if (sourceIndexType) {
+                        inferFromTypes(sourceIndexType, targetNumberIndexType);
                     }
                 }
             }
@@ -7138,46 +7205,33 @@ namespace ts {
                 return originalType;
             }
 
-            function narrowTypeByTypePredicate(type: Type, expr: CallExpression, assumeTrue: boolean): Type {
+            function narrowTypeByTypePredicate(type: Type, callExpression: CallExpression, assumeTrue: boolean): Type {
                 if (type.flags & TypeFlags.Any) {
                     return type;
                 }
-                const signature = getResolvedSignature(expr);
-                const predicateType = getReturnTypeOfSignature(signature);
+                const signature = getResolvedSignature(callExpression);
 
-                if (!predicateType || !(predicateType.flags & TypeFlags.PredicateType)) {
+                const predicate = signature.typePredicate;
+                if (!predicate) {
                     return type;
                 }
-                const predicate = (predicateType as PredicateType).predicate;
+
                 if (isIdentifierTypePredicate(predicate)) {
-                    const callExpression = expr as CallExpression;
                     if (callExpression.arguments[predicate.parameterIndex] &&
                         getSymbolAtTypePredicatePosition(callExpression.arguments[predicate.parameterIndex]) === symbol) {
                         return getNarrowedType(type, predicate.type, assumeTrue);
                     }
                 }
                 else {
-                    const expression = skipParenthesizedNodes(expr.expression);
-                    return narrowTypeByThisTypePredicate(type, predicate, expression, assumeTrue);
+                    const invokedExpression = skipParenthesizedNodes(callExpression.expression);
+                    return narrowTypeByThisTypePredicate(type, predicate, invokedExpression, assumeTrue);
                 }
                 return type;
             }
 
-            function narrowTypeByTypePredicateMember(type: Type, expr: ElementAccessExpression | PropertyAccessExpression, assumeTrue: boolean): Type {
-                if (type.flags & TypeFlags.Any) {
-                    return type;
-                }
-                const memberType = getTypeOfExpression(expr);
-                if (!(memberType.flags & TypeFlags.PredicateType)) {
-                    return type;
-                }
-
-                return narrowTypeByThisTypePredicate(type, (memberType as PredicateType).predicate as ThisTypePredicate, expr, assumeTrue);
-            }
-
-            function narrowTypeByThisTypePredicate(type: Type, predicate: ThisTypePredicate, expression: Expression, assumeTrue: boolean): Type {
-                if (expression.kind === SyntaxKind.ElementAccessExpression || expression.kind === SyntaxKind.PropertyAccessExpression) {
-                    const accessExpression = expression as ElementAccessExpression | PropertyAccessExpression;
+            function narrowTypeByThisTypePredicate(type: Type, predicate: ThisTypePredicate, invokedExpression: Expression, assumeTrue: boolean): Type {
+                if (invokedExpression.kind === SyntaxKind.ElementAccessExpression || invokedExpression.kind === SyntaxKind.PropertyAccessExpression) {
+                    const accessExpression = invokedExpression as ElementAccessExpression | PropertyAccessExpression;
                     const possibleIdentifier = skipParenthesizedNodes(accessExpression.expression);
                     if (possibleIdentifier.kind === SyntaxKind.Identifier && getSymbolAtTypePredicatePosition(possibleIdentifier) === symbol) {
                         return getNarrowedType(type, predicate.type, assumeTrue);
@@ -7191,8 +7245,7 @@ namespace ts {
                 switch (expr.kind) {
                     case SyntaxKind.Identifier:
                     case SyntaxKind.PropertyAccessExpression:
-                    case SyntaxKind.QualifiedName:
-                        return getSymbolOfEntityNameOrPropertyAccessExpression(expr as Node as (EntityName | PropertyAccessExpression));
+                        return getSymbolOfEntityNameOrPropertyAccessExpression(expr as (Identifier | PropertyAccessExpression));
                 }
             }
 
@@ -7226,9 +7279,6 @@ namespace ts {
                             return narrowType(type, (<PrefixUnaryExpression>expr).operand, !assumeTrue);
                         }
                         break;
-                    case SyntaxKind.ElementAccessExpression:
-                    case SyntaxKind.PropertyAccessExpression:
-                        return narrowTypeByTypePredicateMember(type, expr as (ElementAccessExpression | PropertyAccessExpression), assumeTrue);
                 }
                 return type;
             }
@@ -7401,6 +7451,46 @@ namespace ts {
             }
         }
 
+        function findFirstSuperCall(n: Node): Node {
+            if (isSuperCallExpression(n)) {
+                return n;
+            }
+            else if (isFunctionLike(n)) {
+                return undefined;
+            }
+            return forEachChild(n, findFirstSuperCall);
+        }
+
+        /**
+         * Return a cached result if super-statement is already found.
+         * Otherwise, find a super statement in a given constructor function and cache the result in the node-links of the constructor
+         *
+         * @param constructor constructor-function to look for super statement
+         */
+        function getSuperCallInConstructor(constructor: ConstructorDeclaration): ExpressionStatement {
+            const links = getNodeLinks(constructor);
+
+            // Only trying to find super-call if we haven't yet tried to find one.  Once we try, we will record the result
+            if (links.hasSuperCall === undefined) {
+                links.superCall = <ExpressionStatement>findFirstSuperCall(constructor.body);
+                links.hasSuperCall = links.superCall ? true : false;
+            }
+            return links.superCall;
+        }
+
+        /**
+         * Check if the given class-declaration extends null then return true.
+         * Otherwise, return false
+         * @param classDecl a class declaration to check if it extends null
+         */
+        function classDeclarationExtendsNull(classDecl: ClassDeclaration): boolean {
+            const classSymbol = getSymbolOfNode(classDecl);
+            const classInstanceType = <InterfaceType>getDeclaredTypeOfSymbol(classSymbol);
+            const baseConstructorType = getBaseConstructorTypeOfClass(classInstanceType);
+
+            return baseConstructorType === nullType;
+        }
+
         function checkThisExpression(node: Node): Type {
             // Stop at the first arrow function so that we can
             // tell whether 'this' needs to be captured.
@@ -7408,10 +7498,25 @@ namespace ts {
             let needToCaptureLexicalThis = false;
 
             if (container.kind === SyntaxKind.Constructor) {
-                const baseTypeNode = getClassExtendsHeritageClauseElement(<ClassLikeDeclaration>container.parent);
-                if (baseTypeNode && !(getNodeCheckFlags(container) & NodeCheckFlags.HasSeenSuperCall)) {
-                    // In ES6, super inside constructor of class-declaration has to precede "this" accessing
-                    error(node, Diagnostics.super_must_be_called_before_accessing_this_in_the_constructor_of_a_derived_class);
+                const containingClassDecl = <ClassDeclaration>container.parent;
+                const baseTypeNode = getClassExtendsHeritageClauseElement(containingClassDecl);
+
+                // If a containing class does not have extends clause or the class extends null
+                // skip checking whether super statement is called before "this" accessing.
+                if (baseTypeNode && !classDeclarationExtendsNull(containingClassDecl)) {
+                    const superCall = getSuperCallInConstructor(<ConstructorDeclaration>container);
+
+                    // We should give an error in the following cases:
+                    //      - No super-call
+                    //      - "this" is accessing before super-call.
+                    //          i.e super(this)
+                    //              this.x; super();
+                    // We want to make sure that super-call is done before accessing "this" so that
+                    // "this" is not accessed as a parameter of the super-call.
+                    if (!superCall || superCall.end > node.pos) {
+                        // In ES6, super inside constructor of class-declaration has to precede "this" accessing
+                        error(node, Diagnostics.super_must_be_called_before_accessing_this_in_the_constructor_of_a_derived_class);
+                    }
                 }
             }
 
@@ -7897,11 +8002,6 @@ namespace ts {
             return !!(type.flags & TypeFlags.Union ? forEach((<UnionType>type).types, isTupleLikeType) : isTupleLikeType(type));
         }
 
-        // Return true if the given contextual type provides an index signature of the given kind
-        function contextualTypeHasIndexSignature(type: Type, kind: IndexKind): boolean {
-            return !!(type.flags & TypeFlags.Union ? forEach((<UnionType>type).types, t => getIndexInfoOfStructuredType(t, kind)) : getIndexInfoOfStructuredType(type, kind));
-        }
-
         // In an object literal contextually typed by a type T, the contextual type of a property assignment is the type of
         // the matching property in T, if one exists. Otherwise, it is the type of the numeric index signature in T, if one
         // exists. Otherwise, it is the type of the string index signature in T, if one exists.
@@ -8297,6 +8397,17 @@ namespace ts {
             return links.resolvedType;
         }
 
+        function getObjectLiteralIndexInfo(node: ObjectLiteralExpression, properties: Symbol[], kind: IndexKind): IndexInfo {
+            const propTypes: Type[] = [];
+            for (let i = 0; i < properties.length; i++) {
+                if (kind === IndexKind.String || isNumericName(node.properties[i].name)) {
+                    propTypes.push(getTypeOfSymbol(properties[i]));
+                }
+            }
+            const unionType = propTypes.length ? getUnionType(propTypes) : undefinedType;
+            return createIndexInfo(unionType, /*isReadonly*/ false);
+        }
+
         function checkObjectLiteral(node: ObjectLiteralExpression, contextualMapper?: TypeMapper): Type {
             const inDestructuringPattern = isAssignmentTarget(node);
             // Grammar checking
@@ -8308,8 +8419,10 @@ namespace ts {
             const contextualTypeHasPattern = contextualType && contextualType.pattern &&
                 (contextualType.pattern.kind === SyntaxKind.ObjectBindingPattern || contextualType.pattern.kind === SyntaxKind.ObjectLiteralExpression);
             let typeFlags: TypeFlags = 0;
-
             let patternWithComputedProperties = false;
+            let hasComputedStringProperty = false;
+            let hasComputedNumberProperty = false;
+
             for (const memberDecl of node.properties) {
                 let member = memberDecl.symbol;
                 if (memberDecl.kind === SyntaxKind.PropertyAssignment ||
@@ -8373,7 +8486,15 @@ namespace ts {
                     checkAccessorDeclaration(<AccessorDeclaration>memberDecl);
                 }
 
-                if (!hasDynamicName(memberDecl)) {
+                if (hasDynamicName(memberDecl)) {
+                    if (isNumericName(memberDecl.name)) {
+                        hasComputedNumberProperty = true;
+                    }
+                    else {
+                        hasComputedStringProperty = true;
+                    }
+                }
+                else {
                     propertiesTable[member.name] = member;
                 }
                 propertiesArray.push(member);
@@ -8394,8 +8515,8 @@ namespace ts {
                 }
             }
 
-            const stringIndexInfo = getIndexInfo(IndexKind.String);
-            const numberIndexInfo = getIndexInfo(IndexKind.Number);
+            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.FreshObjectLiteral;
             result.flags |= TypeFlags.ObjectLiteral | TypeFlags.ContainsObjectLiteral | freshObjectLiteralFlag | (typeFlags & TypeFlags.PropagatingFlags) | (patternWithComputedProperties ? TypeFlags.ObjectLiteralPatternWithComputedProperties : 0);
@@ -8403,29 +8524,6 @@ namespace ts {
                 result.pattern = node;
             }
             return result;
-
-            function getIndexInfo(kind: IndexKind) {
-                if (contextualType && contextualTypeHasIndexSignature(contextualType, kind)) {
-                    const propTypes: Type[] = [];
-                    for (let i = 0; i < propertiesArray.length; i++) {
-                        const propertyDecl = node.properties[i];
-                        if (kind === IndexKind.String || isNumericName(propertyDecl.name)) {
-                            // Do not call getSymbolOfNode(propertyDecl), as that will get the
-                            // original symbol for the node. We actually want to get the symbol
-                            // created by checkObjectLiteral, since that will be appropriately
-                            // contextually typed and resolved.
-                            const type = getTypeOfSymbol(propertiesArray[i]);
-                            if (!contains(propTypes, type)) {
-                                propTypes.push(type);
-                            }
-                        }
-                    }
-                    const unionType = propTypes.length ? getUnionType(propTypes) : undefinedType;
-                    typeFlags |= unionType.flags;
-                    return createIndexInfo(unionType, /*isReadonly*/ false);
-                }
-                return undefined;
-            }
         }
 
         function checkJsxSelfClosingElement(node: JsxSelfClosingElement) {
@@ -10185,6 +10283,9 @@ namespace ts {
             // that the user will not add any.
             const constructSignatures = getSignaturesOfType(expressionType, SignatureKind.Construct);
             if (constructSignatures.length) {
+                if (!isConstructorAccessible(node, constructSignatures[0])) {
+                    return resolveErrorCall(node);
+                }
                 return resolveCall(node, constructSignatures, candidatesOutArray);
             }
 
@@ -10205,6 +10306,36 @@ namespace ts {
             return resolveErrorCall(node);
         }
 
+        function isConstructorAccessible(node: NewExpression, signature: Signature) {
+            if (!signature || !signature.declaration) {
+                return true;
+            }
+
+            const declaration = signature.declaration;
+            const flags = declaration.flags;
+
+            // Public constructor is accessible.
+            if (!(flags & (NodeFlags.Private | NodeFlags.Protected))) {
+                return true;
+            }
+
+            const declaringClassDeclaration = <ClassLikeDeclaration>getClassLikeDeclarationOfSymbol(declaration.parent.symbol);
+            const declaringClass = <InterfaceType>getDeclaredTypeOfSymbol(declaration.parent.symbol);
+
+            // A private or protected constructor can only be instantiated within it's own class 
+            if (!isNodeWithinClass(node, declaringClassDeclaration)) {
+                if (flags & NodeFlags.Private) {
+                    error(node, Diagnostics.Constructor_of_class_0_is_private_and_only_accessible_within_the_class_declaration, typeToString(declaringClass));
+                }
+                if (flags & NodeFlags.Protected) {
+                    error(node, Diagnostics.Constructor_of_class_0_is_protected_and_only_accessible_within_the_class_declaration, typeToString(declaringClass));
+                }
+                return false;
+            }
+
+            return true;
+        }
+
         function resolveTaggedTemplateExpression(node: TaggedTemplateExpression, candidatesOutArray: Signature[]): Signature {
             const tagType = checkExpression(node.tag);
             const apparentType = getApparentType(tagType);
@@ -10325,14 +10456,11 @@ namespace ts {
             checkGrammarTypeArguments(node, node.typeArguments) || checkGrammarArguments(node, node.arguments);
 
             const signature = getResolvedSignature(node);
-            if (node.expression.kind === SyntaxKind.SuperKeyword) {
-                const containingFunction = getContainingFunction(node.expression);
 
-                if (containingFunction && containingFunction.kind === SyntaxKind.Constructor) {
-                    getNodeLinks(containingFunction).flags |= NodeCheckFlags.HasSeenSuperCall;
-                }
+            if (node.expression.kind === SyntaxKind.SuperKeyword) {
                 return voidType;
             }
+
             if (node.kind === SyntaxKind.NewExpression) {
                 const declaration = signature.declaration;
 
@@ -10621,12 +10749,13 @@ namespace ts {
             return aggregatedTypes;
         }
 
-        /*
-         *TypeScript Specification 1.0 (6.3) - July 2014
-         * An explicitly typed function whose return type isn't the Void type,
-         * the Any type, or a union type containing the Void or Any type as a constituent
-         * must have at least one return statement somewhere in its body.
-         * An exception to this rule is if the function implementation consists of a single 'throw' statement.
+        /**
+         * TypeScript Specification 1.0 (6.3) - July 2014
+         *   An explicitly typed function whose return type isn't the Void type,
+         *   the Any type, or a union type containing the Void or Any type as a constituent
+         *   must have at least one return statement somewhere in its body.
+         *   An exception to this rule is if the function implementation consists of a single 'throw' statement.
+         *
          * @param returnType - return type of the function, can be undefined if return type is not explicitly specified
          */
         function checkAllCodePathsInNonVoidFunctionReturnOrThrow(func: FunctionLikeDeclaration, returnType: Type): void {
@@ -11661,21 +11790,24 @@ namespace ts {
             return -1;
         }
 
-        function checkTypePredicate(node: TypePredicateNode) {
+        function checkTypePredicate(node: TypePredicateNode): void {
             const parent = getTypePredicateParent(node);
             if (!parent) {
+                // The parent must not be valid.
+                error(node, Diagnostics.A_type_predicate_is_only_allowed_in_return_type_position_for_functions_and_methods);
                 return;
             }
-            const returnType = getReturnTypeOfSignature(getSignatureFromDeclaration(parent));
-            if (!returnType || !(returnType.flags & TypeFlags.PredicateType)) {
+
+            const typePredicate = getSignatureFromDeclaration(parent).typePredicate;
+            if (!typePredicate) {
                 return;
             }
+
             const { parameterName } = node;
-            if (parameterName.kind === SyntaxKind.ThisType) {
+            if (isThisTypePredicate(typePredicate)) {
                 getTypeFromThisTypeNode(parameterName as ThisTypeNode);
             }
             else {
-                const typePredicate = <IdentifierTypePredicate>(<PredicateType>returnType).predicate;
                 if (typePredicate.parameterIndex >= 0) {
                     if (parent.parameters[typePredicate.parameterIndex].dotDotDotToken) {
                         error(parameterName,
@@ -11690,12 +11822,8 @@ namespace ts {
                 else if (parameterName) {
                     let hasReportedError = false;
                     for (const { name } of parent.parameters) {
-                        if ((name.kind === SyntaxKind.ObjectBindingPattern ||
-                            name.kind === SyntaxKind.ArrayBindingPattern) &&
-                            checkIfTypePredicateVariableIsDeclaredInBindingPattern(
-                                <BindingPattern>name,
-                                parameterName,
-                                typePredicate.parameterName)) {
+                        if (isBindingPattern(name) &&
+                                checkIfTypePredicateVariableIsDeclaredInBindingPattern(name, parameterName, typePredicate.parameterName)) {
                             hasReportedError = true;
                             break;
                         }
@@ -11763,8 +11891,9 @@ namespace ts {
 
             forEach(node.parameters, checkParameter);
 
-            checkSourceElement(node.type);
-
+            if (node.type) {
+                checkSourceElement(node.type);
+            }
 
             if (produceDiagnostics) {
                 checkCollisionWithArgumentsInGeneratedCode(node);
@@ -11931,13 +12060,11 @@ namespace ts {
             // constructors of derived classes must contain at least one super call somewhere in their function body.
             const containingClassDecl = <ClassDeclaration>node.parent;
             if (getClassExtendsHeritageClauseElement(containingClassDecl)) {
-                const containingClassSymbol = getSymbolOfNode(containingClassDecl);
-                const containingClassInstanceType = <InterfaceType>getDeclaredTypeOfSymbol(containingClassSymbol);
-                const baseConstructorType = getBaseConstructorTypeOfClass(containingClassInstanceType);
-
-                if (containsSuperCall(node.body)) {
-                    if (baseConstructorType === nullType) {
-                        error(node, Diagnostics.A_constructor_cannot_contain_a_super_call_when_its_class_extends_null);
+                const classExtendsNull = classDeclarationExtendsNull(containingClassDecl);
+                const superCall = getSuperCallInConstructor(node);
+                if (superCall) {
+                    if (classExtendsNull) {
+                        error(superCall, Diagnostics.A_constructor_cannot_contain_a_super_call_when_its_class_extends_null);
                     }
 
                     // The first statement in the body of a constructor (excluding prologue directives) must be a super call
@@ -11954,6 +12081,7 @@ namespace ts {
                     if (superCallShouldBeFirst) {
                         const statements = (<Block>node.body).statements;
                         let superCallStatement: ExpressionStatement;
+
                         for (const statement of statements) {
                             if (statement.kind === SyntaxKind.ExpressionStatement && isSuperCallExpression((<ExpressionStatement>statement).expression)) {
                                 superCallStatement = <ExpressionStatement>statement;
@@ -11968,7 +12096,7 @@ namespace ts {
                         }
                     }
                 }
-                else if (baseConstructorType !== nullType) {
+                else if (!classExtendsNull) {
                     error(node, Diagnostics.Constructors_for_derived_classes_must_contain_a_super_call);
                 }
             }
@@ -12159,7 +12287,7 @@ namespace ts {
                             error(o.name, Diagnostics.Overload_signatures_must_all_be_ambient_or_non_ambient);
                         }
                         else if (deviation & (NodeFlags.Private | NodeFlags.Protected)) {
-                            error(o.name, Diagnostics.Overload_signatures_must_all_be_public_private_or_protected);
+                            error(o.name || o, Diagnostics.Overload_signatures_must_all_be_public_private_or_protected);
                         }
                         else if (deviation & NodeFlags.Abstract) {
                             error(o.name, Diagnostics.Overload_signatures_must_all_be_abstract_or_not_abstract);
@@ -12827,7 +12955,7 @@ namespace ts {
             }
 
             if (!compilerOptions.experimentalDecorators) {
-                error(node, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Specify_experimentalDecorators_to_remove_this_warning);
+                error(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);
             }
 
             if (compilerOptions.emitDecoratorMetadata) {
@@ -13721,7 +13849,7 @@ namespace ts {
                             error(node.expression, Diagnostics.Return_type_of_constructor_signature_must_be_assignable_to_the_instance_type_of_the_class);
                         }
                     }
-                    else if (func.type || isGetAccessorWithAnnotatedSetAccessor(func) || returnType.flags & TypeFlags.PredicateType) {
+                    else if (func.type || isGetAccessorWithAnnotatedSetAccessor(func)) {
                         if (isAsyncFunctionLike(func)) {
                             const promisedType = getPromisedType(returnType);
                             const awaitedType = checkAwaitedType(exprType, node.expression, Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
@@ -14028,6 +14156,7 @@ namespace ts {
                 if (baseTypes.length && produceDiagnostics) {
                     const baseType = baseTypes[0];
                     const staticBaseType = getBaseConstructorTypeOfClass(type);
+                    checkBaseTypeAccessibility(staticBaseType, baseTypeNode);
                     checkSourceElement(baseTypeNode.expression);
                     if (baseTypeNode.typeArguments) {
                         forEach(baseTypeNode.typeArguments, checkSourceElement);
@@ -14083,6 +14212,19 @@ namespace ts {
             }
         }
 
+        function checkBaseTypeAccessibility(type: ObjectType, node: ExpressionWithTypeArguments) {
+            const signatures = getSignaturesOfType(type, SignatureKind.Construct);
+            if (signatures.length) {
+                const declaration = signatures[0].declaration;
+                if (declaration && declaration.flags & NodeFlags.Private) {
+                    const typeClassDeclaration = <ClassLikeDeclaration>getClassLikeDeclarationOfSymbol(type.symbol);
+                    if (!isNodeWithinClass(node, typeClassDeclaration)) {
+                        error(node, Diagnostics.Cannot_extend_a_class_0_Class_constructor_is_marked_as_private, (<Identifier>node.expression).text);
+                    }
+                }
+            }
+        }
+
         function getTargetSymbol(s: Symbol) {
             // if symbol is instantiated its flags are not copied from the 'target'
             // so we'll need to get back original 'target' symbol to work with correct set of flags
@@ -15000,11 +15142,20 @@ namespace ts {
                         continue;
                     }
                     const { declarations, flags } = exports[id];
-                    // ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries. (TS Exceptions: namespaces, function overloads, enums, and interfaces)
-                    if (!(flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) && (flags & SymbolFlags.TypeAlias ? declarations.length - 1 : declarations.length) > 1) {
-                        const exportedDeclarations: Declaration[] = filter(declarations, isNotOverload);
-                        if (exportedDeclarations.length > 1) {
-                            for (const declaration of exportedDeclarations) {
+                    // ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries. 
+                    // (TS Exceptions: namespaces, function overloads, enums, and interfaces)
+                    if (flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) {
+                        continue;
+                    }
+                    const exportedDeclarationsCount = countWhere(declarations, isNotOverload);
+                    if (flags & SymbolFlags.TypeAlias && exportedDeclarationsCount <= 2) {
+                        // it is legal to merge type alias with other values
+                        // so count should be either 1 (just type alias) or 2 (type alias + merged value)
+                        continue;
+                    }
+                    if (exportedDeclarationsCount > 1) {
+                        for (const declaration of declarations) {
+                            if (isNotOverload(declaration)) {
                                 diagnostics.add(createDiagnosticForNode(declaration, Diagnostics.Cannot_redeclare_exported_variable_0, id));
                             }
                         }
@@ -15407,6 +15558,18 @@ namespace ts {
             return node.parent && node.parent.kind === SyntaxKind.ExpressionWithTypeArguments;
         }
 
+        function isNodeWithinClass(node: Node, classDeclaration: ClassLikeDeclaration) {
+            while (true) {
+                node = getContainingClass(node);
+                if (!node) {
+                    return false;
+                }
+                if (node === classDeclaration) {
+                    return true;
+                }
+            }
+        }
+
         function getLeftSideOfImportEqualsOrExportAssignment(nodeOnRightSide: EntityName): ImportEqualsDeclaration | ExportAssignment {
             while (nodeOnRightSide.parent.kind === SyntaxKind.QualifiedName) {
                 nodeOnRightSide = <QualifiedName>nodeOnRightSide.parent;
@@ -16290,16 +16453,12 @@ namespace ts {
                     case SyntaxKind.PublicKeyword:
                     case SyntaxKind.ProtectedKeyword:
                     case SyntaxKind.PrivateKeyword:
-                        let text: string;
-                        if (modifier.kind === SyntaxKind.PublicKeyword) {
-                            text = "public";
-                        }
-                        else if (modifier.kind === SyntaxKind.ProtectedKeyword) {
-                            text = "protected";
+                        let text = visibilityToString(modifierToFlag(modifier.kind));
+
+                        if (modifier.kind === SyntaxKind.ProtectedKeyword) {
                             lastProtected = modifier;
                         }
-                        else {
-                            text = "private";
+                        else if (modifier.kind === SyntaxKind.PrivateKeyword) {
                             lastPrivate = modifier;
                         }
 
@@ -16450,12 +16609,6 @@ namespace ts {
                 if (flags & NodeFlags.Abstract) {
                     return grammarErrorOnNode(lastStatic, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "abstract");
                 }
-                else if (flags & NodeFlags.Protected) {
-                    return grammarErrorOnNode(lastProtected, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "protected");
-                }
-                else if (flags & NodeFlags.Private) {
-                    return grammarErrorOnNode(lastPrivate, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "private");
-                }
                 else if (flags & NodeFlags.Async) {
                     return grammarErrorOnNode(lastAsync, Diagnostics._0_modifier_cannot_appear_on_a_constructor_declaration, "async");
                 }
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index d8bdd2fb52f..1328a2e8484 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -1313,7 +1313,7 @@ namespace ts {
                 if (node.kind === SyntaxKind.FunctionDeclaration) {
                     emitModuleElementDeclarationFlags(node);
                 }
-                else if (node.kind === SyntaxKind.MethodDeclaration) {
+                else if (node.kind === SyntaxKind.MethodDeclaration || node.kind === SyntaxKind.Constructor) {
                     emitClassMemberDeclarationFlags(node.flags);
                 }
                 if (node.kind === SyntaxKind.FunctionDeclaration) {
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 6978a9ad611..2119d0f0c53 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -687,7 +687,7 @@
         "category": "Error",
         "code": 1218
     },
-    "Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.": {
+    "Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.": {
         "category": "Error",
         "code": 1219
     },
@@ -723,6 +723,10 @@
         "category": "Error",
         "code": 1227
     },
+    "A type predicate is only allowed in return type position for functions and methods.": {
+        "category": "Error",
+        "code": 1228
+    },
     "A type predicate cannot reference a rest parameter.": {
         "category": "Error",
         "code": 1229
@@ -1699,6 +1703,10 @@
         "category": "Error",
         "code": 2529
     },
+    "Property '{0}' is incompatible with index signature.": {
+        "category": "Error",
+        "code": 2530
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
@@ -1819,6 +1827,22 @@
         "category": "Error",
         "code": 2671
     },
+    "Cannot assign a '{0}' constructor type to a '{1}' constructor type.": {
+        "category": "Error",
+        "code": 2672
+    },
+    "Constructor of class '{0}' is private and only accessible within the class declaration.": {
+        "category": "Error",
+        "code": 2673
+    },
+    "Constructor of class '{0}' is protected and only accessible within the class declaration.": {
+        "category": "Error",
+        "code": 2674
+    },
+    "Cannot extend a class '{0}'. Class constructor is marked as private.": {
+        "category": "Error",
+        "code": 2675
+    },
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
         "code": 4000
@@ -2733,11 +2757,6 @@
         "category": "Error",
         "code": 8016
     },
-    "'decorators' can only be used in a .ts file.": {
-        "category": "Error",
-        "code": 8017
-    },
-
     "Only identifiers/qualified-names with optional type arguments are currently supported in a class 'extends' clauses.": {
         "category": "Error",
         "code": 9002
@@ -2786,4 +2805,4 @@
         "category": "Error",
         "code": 17009
     }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index f3a9e5cbf85..0d3cdfe733e 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -1940,7 +1940,7 @@ namespace ts {
             return finishNode(node);
         }
 
-        function parseTypePredicate(lhs: Identifier | ThisTypeNode): TypePredicateNode {
+        function parseThisTypePredicate(lhs: ThisTypeNode): TypePredicateNode {
             nextToken();
             const node = createNode(SyntaxKind.TypePredicate, lhs.pos) as TypePredicateNode;
             node.parameterName = lhs;
@@ -2365,7 +2365,7 @@ namespace ts {
                 case SyntaxKind.ThisKeyword: {
                     const thisKeyword = parseThisTypeNode();
                     if (token === SyntaxKind.IsKeyword && !scanner.hasPrecedingLineBreak()) {
-                        return parseTypePredicate(thisKeyword);
+                        return parseThisTypePredicate(thisKeyword);
                     }
                     else {
                         return thisKeyword;
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 7a2e65ed33b..d41f34df0b3 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -533,18 +533,25 @@ namespace ts {
         }
 
         let referencedSourceFile: string;
-        while (true) {
-            const searchName = normalizePath(combinePaths(containingDirectory, moduleName));
-            referencedSourceFile = loadModuleFromFile(searchName, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
-            if (referencedSourceFile) {
-                break;
+        if (moduleHasNonRelativeName(moduleName)) {
+            while (true) {
+                const searchName = normalizePath(combinePaths(containingDirectory, moduleName));
+                referencedSourceFile = loadModuleFromFile(searchName, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+                if (referencedSourceFile) {
+                    break;
+                }
+                const parentPath = getDirectoryPath(containingDirectory);
+                if (parentPath === containingDirectory) {
+                    break;
+                }
+                containingDirectory = parentPath;
             }
-            const parentPath = getDirectoryPath(containingDirectory);
-            if (parentPath === containingDirectory) {
-                break;
-            }
-            containingDirectory = parentPath;
         }
+        else {
+            const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
+            referencedSourceFile = loadModuleFromFile(candidate, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+        }
+
 
         return referencedSourceFile
             ? { resolvedModule: { resolvedFileName: referencedSourceFile  }, failedLookupLocations }
@@ -946,13 +953,27 @@ namespace ts {
         }
 
         function emitWorker(program: Program, sourceFile: SourceFile, writeFileCallback: WriteFileCallback, cancellationToken: CancellationToken): EmitResult {
+            let declarationDiagnostics: Diagnostic[] = [];
+
+            if (options.noEmit) {
+                return { diagnostics: declarationDiagnostics, sourceMaps: undefined, emitSkipped: true };
+            }
+
             // If the noEmitOnError flag is set, then check if we have any errors so far.  If so,
             // immediately bail out.  Note that we pass 'undefined' for 'sourceFile' so that we
             // get any preEmit diagnostics, not just the ones
             if (options.noEmitOnError) {
-                const preEmitDiagnostics = getPreEmitDiagnostics(program, /*sourceFile:*/ undefined, cancellationToken);
-                if (preEmitDiagnostics.length > 0) {
-                    return { diagnostics: preEmitDiagnostics, sourceMaps: undefined, emitSkipped: true };
+                const diagnostics = program.getOptionsDiagnostics(cancellationToken).concat(
+                    program.getSyntacticDiagnostics(sourceFile, cancellationToken),
+                    program.getGlobalDiagnostics(cancellationToken),
+                    program.getSemanticDiagnostics(sourceFile, cancellationToken));
+
+                if (diagnostics.length === 0 && program.getCompilerOptions().declaration) {
+                    declarationDiagnostics = program.getDeclarationDiagnostics(/*sourceFile*/ undefined, cancellationToken);
+                }
+
+                if (diagnostics.length > 0 || declarationDiagnostics.length > 0) {
+                    return { diagnostics, sourceMaps: undefined, emitSkipped: true };
                 }
             }
 
@@ -1169,7 +1190,9 @@ namespace ts {
                             diagnostics.push(createDiagnosticForNode(typeAssertionExpression.type, Diagnostics.type_assertion_expressions_can_only_be_used_in_a_ts_file));
                             return true;
                         case SyntaxKind.Decorator:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.decorators_can_only_be_used_in_a_ts_file));
+                            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;
                     }
 
diff --git a/src/compiler/tsc.ts b/src/compiler/tsc.ts
index c69bfca1877..e5b85a7391e 100644
--- a/src/compiler/tsc.ts
+++ b/src/compiler/tsc.ts
@@ -590,30 +590,21 @@ namespace ts {
                 }
             }
 
-            reportDiagnostics(diagnostics, compilerHost);
-
-            // If the user doesn't want us to emit, then we're done at this point.
-            if (compilerOptions.noEmit) {
-                return diagnostics.length
-                    ? ExitStatus.DiagnosticsPresent_OutputsSkipped
-                    : ExitStatus.Success;
-            }
-
             // Otherwise, emit and report any errors we ran into.
             const emitOutput = program.emit();
-            reportDiagnostics(emitOutput.diagnostics, compilerHost);
+            diagnostics = diagnostics.concat(emitOutput.diagnostics);
 
-            // If the emitter didn't emit anything, then pass that value along.
-            if (emitOutput.emitSkipped) {
+            reportDiagnostics(sortAndDeduplicateDiagnostics(diagnostics), compilerHost);
+
+            if (emitOutput.emitSkipped && diagnostics.length > 0) {
+                // If the emitter didn't emit anything, then pass that value along.
                 return ExitStatus.DiagnosticsPresent_OutputsSkipped;
             }
-
-            // The emitter emitted something, inform the caller if that happened in the presence
-            // of diagnostics or not.
-            if (diagnostics.length > 0 || emitOutput.diagnostics.length > 0) {
+            else if (diagnostics.length > 0) {
+                // The emitter emitted something, inform the caller if that happened in the presence
+                // of diagnostics or not.
                 return ExitStatus.DiagnosticsPresent_OutputsGenerated;
             }
-
             return ExitStatus.Success;
         }
     }
@@ -719,14 +710,16 @@ namespace ts {
         else {
             const compilerOptions = extend(options, defaultInitCompilerOptions);
             const configurations: any = {
-                compilerOptions: serializeCompilerOptions(compilerOptions),
-                exclude: ["node_modules"]
+                compilerOptions: serializeCompilerOptions(compilerOptions)
             };
 
             if (fileNames && fileNames.length) {
                 // only set the files property if we have at least one file
                 configurations.files = fileNames;
             }
+            else {
+                configurations.exclude = ["node_modules"];
+            }
 
             sys.writeFile(file, JSON.stringify(configurations, undefined, 4));
             reportDiagnostic(createCompilerDiagnostic(Diagnostics.Successfully_created_a_tsconfig_json_file), /* compilerHost */ undefined);
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index ca297c087cf..5460f162935 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -1,6 +1,5 @@
 {
     "compilerOptions": {
-        "module": "commonjs",
         "noImplicitAny": true,
         "removeComments": true,
         "preserveConstEnums": true,
@@ -8,9 +7,9 @@
         "sourceMap": true
     },
     "files": [
+        "types.ts",
         "core.ts",
         "sys.ts",
-        "types.ts",
         "diagnosticInformationMap.generated.ts",
         "scanner.ts",
         "parser.ts",
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index af4045cf643..11273a34bf8 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -428,7 +428,6 @@ namespace ts {
         IntrinsicElement = IntrinsicNamedElement | IntrinsicIndexedElement,
     }
 
-
     /* @internal */
     export const enum RelationComparisonResult {
         Succeeded = 1, // Should be truthy
@@ -1693,6 +1692,7 @@ namespace ts {
 
     export interface EmitResult {
         emitSkipped: boolean;
+        /** Contains declaration emit diagnostics */
         diagnostics: Diagnostic[];
         /* @internal */ sourceMaps: SourceMapData[];  // Array of sourceMapData if compiler emitted sourcemaps
     }
@@ -1761,6 +1761,7 @@ namespace ts {
         buildSignatureDisplay(signatures: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind): void;
         buildParameterDisplay(parameter: Symbol, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildTypeParameterDisplay(tp: TypeParameter, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
+        buildTypePredicateDisplay(predicate: TypePredicate, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildTypeParameterDisplayFromSymbol(symbol: Symbol, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildDisplayForParametersAndDelimiters(parameters: Symbol[], writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildDisplayForTypeParametersAndDelimiters(typeParameters: TypeParameter[], writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
@@ -1826,22 +1827,24 @@ namespace ts {
         Identifier
     }
 
-    export interface TypePredicate {
+    export interface TypePredicateBase {
         kind: TypePredicateKind;
         type: Type;
     }
 
     // @kind (TypePredicateKind.This)
-    export interface ThisTypePredicate extends TypePredicate {
+    export interface ThisTypePredicate extends TypePredicateBase {
         _thisTypePredicateBrand: any;
     }
 
     // @kind (TypePredicateKind.Identifier)
-    export interface IdentifierTypePredicate extends TypePredicate {
+    export interface IdentifierTypePredicate extends TypePredicateBase {
         parameterName: string;
         parameterIndex: number;
     }
 
+    export type TypePredicate = IdentifierTypePredicate | ThisTypePredicate;
+
     /* @internal */
     export type AnyImportSyntax = ImportDeclaration | ImportEqualsDeclaration;
 
@@ -2049,10 +2052,9 @@ namespace ts {
         LoopWithCapturedBlockScopedBinding  = 0x00010000, // Loop that contains block scoped variable captured in closure
         CapturedBlockScopedBinding          = 0x00020000, // Block-scoped binding that is captured in some function
         BlockScopedBindingInLoop            = 0x00040000, // Block-scoped binding with declaration nested inside iteration statement
-        HasSeenSuperCall                    = 0x00080000, // Set during the binding when encounter 'super'
-        ClassWithBodyScopedClassBinding     = 0x00100000, // Decorated class that contains a binding to itself inside of the class body.
-        BodyScopedClassBinding              = 0x00200000, // Binding to a decorated class inside of the class's body.
-        NeedsLoopOutParameter               = 0x00400000, // Block scoped binding whose value should be explicitly copied outside of the converted loop
+        ClassWithBodyScopedClassBinding     = 0x00080000, // Decorated class that contains a binding to itself inside of the class body.
+        BodyScopedClassBinding              = 0x00100000, // Binding to a decorated class inside of the class's body.
+        NeedsLoopOutParameter               = 0x00200000, // Block scoped binding whose value should be explicitly copied outside of the converted loop
     }
 
     /* @internal */
@@ -2072,6 +2074,8 @@ namespace ts {
         importOnRightSide?: Symbol;       // for import declarations - import that appear on the right side
         jsxFlags?: JsxFlags;              // flags for knowing what kind of element/attributes we're dealing with
         resolvedJsxType?: Type;           // resolved element attributes type of a JSX openinglike element
+        hasSuperCall?: boolean;           // recorded result when we try to find super-call. We only try to find one if this flag is undefined, indicating that we haven't made an attempt.
+        superCall?: ExpressionStatement;  // Cached first super-call found in the constructor. Used in checking whether super is called before this-accessing 
     }
 
     export const enum TypeFlags {
@@ -2106,7 +2110,6 @@ namespace ts {
         ESSymbol                = 0x01000000,  // Type of symbol primitive introduced in ES6
         ThisType                = 0x02000000,  // This type
         ObjectLiteralPatternWithComputedProperties = 0x04000000,  // Object literal type implied by binding pattern has computed properties
-        PredicateType           = 0x08000000,  // Predicate types are also Boolean types, but should not be considered Intrinsics - there's no way to capture this with flags
 
         /* @internal */
         Intrinsic = Any | String | Number | Boolean | ESSymbol | Void | Undefined,
@@ -2118,7 +2121,7 @@ namespace ts {
         UnionOrIntersection = Union | Intersection,
         StructuredType = ObjectType | Union | Intersection,
         /* @internal */
-        RequiresWidening = ContainsUndefined | ContainsObjectLiteral | PredicateType,
+        RequiresWidening = ContainsUndefined | ContainsObjectLiteral,
         /* @internal */
         PropagatingFlags = ContainsUndefined | ContainsObjectLiteral | ContainsAnyFunctionType
     }
@@ -2140,11 +2143,6 @@ namespace ts {
         intrinsicName: string;  // Name of intrinsic type
     }
 
-    // Predicate types (TypeFlags.Predicate)
-    export interface PredicateType extends Type {
-        predicate: ThisTypePredicate | IdentifierTypePredicate;
-    }
-
     // String literal types (TypeFlags.StringLiteral)
     export interface StringLiteralType extends Type {
         text: string;  // Text of string literal
@@ -2281,6 +2279,8 @@ namespace ts {
         erasedSignatureCache?: Signature;   // Erased version of signature (deferred)
         /* @internal */
         isolatedSignatureType?: ObjectType; // A manufactured type that just contains the signature for purposes of signature comparison
+        /* @internal */
+        typePredicate?: TypePredicate;
     }
 
     export const enum IndexKind {
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 50005d5c070..7012326fa98 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -748,6 +748,10 @@ namespace ts {
         return predicate && predicate.kind === TypePredicateKind.Identifier;
     }
 
+    export function isThisTypePredicate(predicate: TypePredicate): predicate is ThisTypePredicate {
+        return predicate && predicate.kind === TypePredicateKind.This;
+    }
+
     export function getContainingFunction(node: Node): FunctionLikeDeclaration {
         while (true) {
             node = node.parent;
diff --git a/src/server/tsconfig.json b/src/server/tsconfig.json
index 2c8538c61e3..0772210cb15 100644
--- a/src/server/tsconfig.json
+++ b/src/server/tsconfig.json
@@ -1,6 +1,5 @@
 {
     "compilerOptions": {
-        "module": "commonjs",
         "noImplicitAny": true,
         "removeComments": true,
         "preserveConstEnums": true,
diff --git a/src/services/tsconfig.json b/src/services/tsconfig.json
index 5dcee789243..001071ed88d 100644
--- a/src/services/tsconfig.json
+++ b/src/services/tsconfig.json
@@ -1,6 +1,5 @@
 {
     "compilerOptions": {
-        "module": "commonjs",
         "noImplicitAny": true,
         "removeComments": true,
         "preserveConstEnums": true,
diff --git a/tests/baselines/reference/APISample_compile.js b/tests/baselines/reference/APISample_compile.js
index 3830e53697c..5f55c04c9f9 100644
--- a/tests/baselines/reference/APISample_compile.js
+++ b/tests/baselines/reference/APISample_compile.js
@@ -16,7 +16,7 @@ export function compile(fileNames: string[], options: ts.CompilerOptions): void
     var program = ts.createProgram(fileNames, options);
     var emitResult = program.emit();
 
-    var allDiagnostics = ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics);
+    var allDiagnostics = ts.getPreEmitDiagnostics(program);
 
     allDiagnostics.forEach(diagnostic => {
         var { line, character } = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
@@ -45,7 +45,7 @@ var ts = require("typescript");
 function compile(fileNames, options) {
     var program = ts.createProgram(fileNames, options);
     var emitResult = program.emit();
-    var allDiagnostics = ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics);
+    var allDiagnostics = ts.getPreEmitDiagnostics(program);
     allDiagnostics.forEach(function (diagnostic) {
         var _a = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start), line = _a.line, character = _a.character;
         var message = ts.flattenDiagnosticMessageText(diagnostic.messageText, '\n');
diff --git a/tests/baselines/reference/Protected3.errors.txt b/tests/baselines/reference/Protected3.errors.txt
deleted file mode 100644
index 688422a1e0f..00000000000
--- a/tests/baselines/reference/Protected3.errors.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-tests/cases/conformance/parser/ecmascript5/Protected/Protected3.ts(2,3): error TS1089: 'protected' modifier cannot appear on a constructor declaration.
-
-
-==== tests/cases/conformance/parser/ecmascript5/Protected/Protected3.ts (1 errors) ====
-    class C {
-      protected constructor() { }
-      ~~~~~~~~~
-!!! error TS1089: 'protected' modifier cannot appear on a constructor declaration.
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/Protected3.symbols b/tests/baselines/reference/Protected3.symbols
new file mode 100644
index 00000000000..a9882189902
--- /dev/null
+++ b/tests/baselines/reference/Protected3.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/conformance/parser/ecmascript5/Protected/Protected3.ts ===
+class C {
+>C : Symbol(C, Decl(Protected3.ts, 0, 0))
+
+  protected constructor() { }
+}
diff --git a/tests/baselines/reference/Protected3.types b/tests/baselines/reference/Protected3.types
new file mode 100644
index 00000000000..d3f938a4431
--- /dev/null
+++ b/tests/baselines/reference/Protected3.types
@@ -0,0 +1,6 @@
+=== tests/cases/conformance/parser/ecmascript5/Protected/Protected3.ts ===
+class C {
+>C : C
+
+  protected constructor() { }
+}
diff --git a/tests/baselines/reference/arrayBufferIsViewNarrowsType.types b/tests/baselines/reference/arrayBufferIsViewNarrowsType.types
index b9d4f3db81b..129b7d601d8 100644
--- a/tests/baselines/reference/arrayBufferIsViewNarrowsType.types
+++ b/tests/baselines/reference/arrayBufferIsViewNarrowsType.types
@@ -4,7 +4,7 @@ var obj: Object;
 >Object : Object
 
 if (ArrayBuffer.isView(obj)) {
->ArrayBuffer.isView(obj) : arg is ArrayBufferView
+>ArrayBuffer.isView(obj) : boolean
 >ArrayBuffer.isView : (arg: any) => arg is ArrayBufferView
 >ArrayBuffer : ArrayBufferConstructor
 >isView : (arg: any) => arg is ArrayBufferView
diff --git a/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt b/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt
index eb5020e97f9..e99cac7968c 100644
--- a/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt
+++ b/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt
@@ -1,10 +1,8 @@
-tests/cases/conformance/types/members/augmentedTypeAssignmentCompatIndexSignature.ts(15,5): error TS2322: Type '{}' is not assignable to type '{ [n: number]: Foo; }'.
-  Index signature is missing in type '{}'.
 tests/cases/conformance/types/members/augmentedTypeAssignmentCompatIndexSignature.ts(19,5): error TS2322: Type '() => void' is not assignable to type '{ [n: number]: Bar; }'.
   Index signature is missing in type '() => void'.
 
 
-==== tests/cases/conformance/types/members/augmentedTypeAssignmentCompatIndexSignature.ts (2 errors) ====
+==== tests/cases/conformance/types/members/augmentedTypeAssignmentCompatIndexSignature.ts (1 errors) ====
     interface Foo { a }
     interface Bar { b }
     
@@ -20,9 +18,6 @@ tests/cases/conformance/types/members/augmentedTypeAssignmentCompatIndexSignatur
     var f = () => { };
     
     var v1: {
-        ~~
-!!! error TS2322: Type '{}' is not assignable to type '{ [n: number]: Foo; }'.
-!!! error TS2322:   Index signature is missing in type '{}'.
         [n: number]: Foo
     } = o; // Should be allowed
     
diff --git a/tests/baselines/reference/badOverloadError.types b/tests/baselines/reference/badOverloadError.types
index b8ae583a73c..198582af2db 100644
--- a/tests/baselines/reference/badOverloadError.types
+++ b/tests/baselines/reference/badOverloadError.types
@@ -6,6 +6,6 @@ function method() {
 >dictionary : { [index: string]: string; }
 ><{ [index: string]: string; }>{} : { [index: string]: string; }
 >index : string
->{} : { [x: string]: undefined; }
+>{} : {}
 }
 
diff --git a/tests/baselines/reference/bestCommonTypeWithContextualTyping.types b/tests/baselines/reference/bestCommonTypeWithContextualTyping.types
index 628fe82012a..5baca43b752 100644
--- a/tests/baselines/reference/bestCommonTypeWithContextualTyping.types
+++ b/tests/baselines/reference/bestCommonTypeWithContextualTyping.types
@@ -36,7 +36,7 @@ var obj: { [s: string]: Contextual } = { s: e }; // { s: Ellement; [s: string]:
 >obj : { [s: string]: Contextual; }
 >s : string
 >Contextual : Contextual
->{ s: e } : { [x: string]: Ellement; s: Ellement; }
+>{ s: e } : { s: Ellement; }
 >s : Ellement
 >e : Ellement
 
diff --git a/tests/baselines/reference/classConstructorAccessibility.errors.txt b/tests/baselines/reference/classConstructorAccessibility.errors.txt
index c22f3593bc5..c79633ba33d 100644
--- a/tests/baselines/reference/classConstructorAccessibility.errors.txt
+++ b/tests/baselines/reference/classConstructorAccessibility.errors.txt
@@ -1,29 +1,30 @@
-tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(6,5): error TS1089: 'private' modifier cannot appear on a constructor declaration.
-tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(10,5): error TS1089: 'protected' modifier cannot appear on a constructor declaration.
-tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(23,9): error TS1089: 'private' modifier cannot appear on a constructor declaration.
-tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(27,9): error TS1089: 'protected' modifier cannot appear on a constructor declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(15,9): error TS2673: Constructor of class 'D' is private and only accessible within the class declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(16,9): error TS2674: Constructor of class 'E' is protected and only accessible within the class declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(32,13): error TS2673: Constructor of class 'D<T>' is private and only accessible within the class declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts(33,13): error TS2674: Constructor of class 'E<T>' is protected and only accessible within the class declaration.
 
 
 ==== tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts (4 errors) ====
+    
     class C {
         public constructor(public x: number) { }
     }
     
     class D {
-        private constructor(public x: number) { } // error
-        ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
+        private constructor(public x: number) { }
     }
     
     class E {
-        protected constructor(public x: number) { } // error
-        ~~~~~~~~~
-!!! error TS1089: 'protected' modifier cannot appear on a constructor declaration.
+        protected constructor(public x: number) { }
     }
     
     var c = new C(1);
-    var d = new D(1);
-    var e = new E(1);
+    var d = new D(1); // error
+            ~~~~~~~~
+!!! error TS2673: Constructor of class 'D' is private and only accessible within the class declaration.
+    var e = new E(1); // error
+            ~~~~~~~~
+!!! error TS2674: Constructor of class 'E' is protected and only accessible within the class declaration.
     
     module Generic {
         class C<T> {
@@ -31,19 +32,19 @@ tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessib
         }
     
         class D<T> {
-            private constructor(public x: T) { } // error
-            ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
+            private constructor(public x: T) { }
         }
     
         class E<T> {
-            protected constructor(public x: T) { } // error
-            ~~~~~~~~~
-!!! error TS1089: 'protected' modifier cannot appear on a constructor declaration.
+            protected constructor(public x: T) { }
         }
     
         var c = new C(1);
-        var d = new D(1);
-        var e = new E(1);
+        var d = new D(1); // error
+                ~~~~~~~~
+!!! error TS2673: Constructor of class 'D<T>' is private and only accessible within the class declaration.
+        var e = new E(1); // error
+                ~~~~~~~~
+!!! error TS2674: Constructor of class 'E<T>' is protected and only accessible within the class declaration.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/classConstructorAccessibility.js b/tests/baselines/reference/classConstructorAccessibility.js
index fed96385845..efc3f3c273c 100644
--- a/tests/baselines/reference/classConstructorAccessibility.js
+++ b/tests/baselines/reference/classConstructorAccessibility.js
@@ -1,19 +1,20 @@
 //// [classConstructorAccessibility.ts]
+
 class C {
     public constructor(public x: number) { }
 }
 
 class D {
-    private constructor(public x: number) { } // error
+    private constructor(public x: number) { }
 }
 
 class E {
-    protected constructor(public x: number) { } // error
+    protected constructor(public x: number) { }
 }
 
 var c = new C(1);
-var d = new D(1);
-var e = new E(1);
+var d = new D(1); // error
+var e = new E(1); // error
 
 module Generic {
     class C<T> {
@@ -21,16 +22,16 @@ module Generic {
     }
 
     class D<T> {
-        private constructor(public x: T) { } // error
+        private constructor(public x: T) { }
     }
 
     class E<T> {
-        protected constructor(public x: T) { } // error
+        protected constructor(public x: T) { }
     }
 
     var c = new C(1);
-    var d = new D(1);
-    var e = new E(1);
+    var d = new D(1); // error
+    var e = new E(1); // error
 }
 
 
@@ -44,18 +45,18 @@ var C = (function () {
 var D = (function () {
     function D(x) {
         this.x = x;
-    } // error
+    }
     return D;
 }());
 var E = (function () {
     function E(x) {
         this.x = x;
-    } // error
+    }
     return E;
 }());
 var c = new C(1);
-var d = new D(1);
-var e = new E(1);
+var d = new D(1); // error
+var e = new E(1); // error
 var Generic;
 (function (Generic) {
     var C = (function () {
@@ -67,16 +68,36 @@ var Generic;
     var D = (function () {
         function D(x) {
             this.x = x;
-        } // error
+        }
         return D;
     }());
     var E = (function () {
         function E(x) {
             this.x = x;
-        } // error
+        }
         return E;
     }());
     var c = new C(1);
-    var d = new D(1);
-    var e = new E(1);
+    var d = new D(1); // error
+    var e = new E(1); // error
 })(Generic || (Generic = {}));
+
+
+//// [classConstructorAccessibility.d.ts]
+declare class C {
+    x: number;
+    constructor(x: number);
+}
+declare class D {
+    x: number;
+    private constructor(x);
+}
+declare class E {
+    x: number;
+    protected constructor(x: number);
+}
+declare var c: C;
+declare var d: any;
+declare var e: any;
+declare module Generic {
+}
diff --git a/tests/baselines/reference/classConstructorAccessibility2.errors.txt b/tests/baselines/reference/classConstructorAccessibility2.errors.txt
new file mode 100644
index 00000000000..7bd784ac268
--- /dev/null
+++ b/tests/baselines/reference/classConstructorAccessibility2.errors.txt
@@ -0,0 +1,59 @@
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts(26,28): error TS2674: Constructor of class 'BaseB' is protected and only accessible within the class declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts(29,24): error TS2675: Cannot extend a class 'BaseC'. Class constructor is marked as private.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts(32,28): error TS2673: Constructor of class 'BaseC' is private and only accessible within the class declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts(36,10): error TS2674: Constructor of class 'BaseB' is protected and only accessible within the class declaration.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts(37,10): error TS2673: Constructor of class 'BaseC' is private and only accessible within the class declaration.
+
+
+==== tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts (5 errors) ====
+    
+    class BaseA {
+        public constructor(public x: number) { }
+        createInstance() { new BaseA(1); }
+    }
+    
+    class BaseB {
+        protected constructor(public x: number) { }
+        createInstance() { new BaseB(1); }
+    }
+    
+    class BaseC {
+         private constructor(public x: number) { }
+         createInstance() { new BaseC(1); }
+    }
+    
+    class DerivedA extends BaseA {
+        constructor(public x: number) { super(x); }
+        createInstance() { new DerivedA(1); }
+        createBaseInstance() { new BaseA(1); }
+    }
+    
+    class DerivedB extends BaseB {
+        constructor(public x: number) { super(x); }
+        createInstance() { new DerivedB(1); }
+        createBaseInstance() { new BaseB(1); } // error
+                               ~~~~~~~~~~~~
+!!! error TS2674: Constructor of class 'BaseB' is protected and only accessible within the class declaration.
+    }
+    
+    class DerivedC extends BaseC { // error
+                           ~~~~~
+!!! error TS2675: Cannot extend a class 'BaseC'. Class constructor is marked as private.
+        constructor(public x: number) { super(x); }
+        createInstance() { new DerivedC(1); }
+        createBaseInstance() { new BaseC(1); } // error
+                               ~~~~~~~~~~~~
+!!! error TS2673: Constructor of class 'BaseC' is private and only accessible within the class declaration.
+    }
+    
+    var ba = new BaseA(1);
+    var bb = new BaseB(1); // error
+             ~~~~~~~~~~~~
+!!! error TS2674: Constructor of class 'BaseB' is protected and only accessible within the class declaration.
+    var bc = new BaseC(1); // error
+             ~~~~~~~~~~~~
+!!! error TS2673: Constructor of class 'BaseC' is private and only accessible within the class declaration.
+    
+    var da = new DerivedA(1);
+    var db = new DerivedB(1);
+    var dc = new DerivedC(1);
\ No newline at end of file
diff --git a/tests/baselines/reference/classConstructorAccessibility2.js b/tests/baselines/reference/classConstructorAccessibility2.js
new file mode 100644
index 00000000000..e19589ece45
--- /dev/null
+++ b/tests/baselines/reference/classConstructorAccessibility2.js
@@ -0,0 +1,148 @@
+//// [classConstructorAccessibility2.ts]
+
+class BaseA {
+    public constructor(public x: number) { }
+    createInstance() { new BaseA(1); }
+}
+
+class BaseB {
+    protected constructor(public x: number) { }
+    createInstance() { new BaseB(1); }
+}
+
+class BaseC {
+     private constructor(public x: number) { }
+     createInstance() { new BaseC(1); }
+}
+
+class DerivedA extends BaseA {
+    constructor(public x: number) { super(x); }
+    createInstance() { new DerivedA(1); }
+    createBaseInstance() { new BaseA(1); }
+}
+
+class DerivedB extends BaseB {
+    constructor(public x: number) { super(x); }
+    createInstance() { new DerivedB(1); }
+    createBaseInstance() { new BaseB(1); } // error
+}
+
+class DerivedC extends BaseC { // error
+    constructor(public x: number) { super(x); }
+    createInstance() { new DerivedC(1); }
+    createBaseInstance() { new BaseC(1); } // error
+}
+
+var ba = new BaseA(1);
+var bb = new BaseB(1); // error
+var bc = new BaseC(1); // error
+
+var da = new DerivedA(1);
+var db = new DerivedB(1);
+var dc = new DerivedC(1);
+
+//// [classConstructorAccessibility2.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var BaseA = (function () {
+    function BaseA(x) {
+        this.x = x;
+    }
+    BaseA.prototype.createInstance = function () { new BaseA(1); };
+    return BaseA;
+}());
+var BaseB = (function () {
+    function BaseB(x) {
+        this.x = x;
+    }
+    BaseB.prototype.createInstance = function () { new BaseB(1); };
+    return BaseB;
+}());
+var BaseC = (function () {
+    function BaseC(x) {
+        this.x = x;
+    }
+    BaseC.prototype.createInstance = function () { new BaseC(1); };
+    return BaseC;
+}());
+var DerivedA = (function (_super) {
+    __extends(DerivedA, _super);
+    function DerivedA(x) {
+        _super.call(this, x);
+        this.x = x;
+    }
+    DerivedA.prototype.createInstance = function () { new DerivedA(1); };
+    DerivedA.prototype.createBaseInstance = function () { new BaseA(1); };
+    return DerivedA;
+}(BaseA));
+var DerivedB = (function (_super) {
+    __extends(DerivedB, _super);
+    function DerivedB(x) {
+        _super.call(this, x);
+        this.x = x;
+    }
+    DerivedB.prototype.createInstance = function () { new DerivedB(1); };
+    DerivedB.prototype.createBaseInstance = function () { new BaseB(1); }; // error
+    return DerivedB;
+}(BaseB));
+var DerivedC = (function (_super) {
+    __extends(DerivedC, _super);
+    function DerivedC(x) {
+        _super.call(this, x);
+        this.x = x;
+    }
+    DerivedC.prototype.createInstance = function () { new DerivedC(1); };
+    DerivedC.prototype.createBaseInstance = function () { new BaseC(1); }; // error
+    return DerivedC;
+}(BaseC));
+var ba = new BaseA(1);
+var bb = new BaseB(1); // error
+var bc = new BaseC(1); // error
+var da = new DerivedA(1);
+var db = new DerivedB(1);
+var dc = new DerivedC(1);
+
+
+//// [classConstructorAccessibility2.d.ts]
+declare class BaseA {
+    x: number;
+    constructor(x: number);
+    createInstance(): void;
+}
+declare class BaseB {
+    x: number;
+    protected constructor(x: number);
+    createInstance(): void;
+}
+declare class BaseC {
+    x: number;
+    private constructor(x);
+    createInstance(): void;
+}
+declare class DerivedA extends BaseA {
+    x: number;
+    constructor(x: number);
+    createInstance(): void;
+    createBaseInstance(): void;
+}
+declare class DerivedB extends BaseB {
+    x: number;
+    constructor(x: number);
+    createInstance(): void;
+    createBaseInstance(): void;
+}
+declare class DerivedC extends BaseC {
+    x: number;
+    constructor(x: number);
+    createInstance(): void;
+    createBaseInstance(): void;
+}
+declare var ba: BaseA;
+declare var bb: any;
+declare var bc: any;
+declare var da: DerivedA;
+declare var db: DerivedB;
+declare var dc: DerivedC;
diff --git a/tests/baselines/reference/classConstructorAccessibility3.errors.txt b/tests/baselines/reference/classConstructorAccessibility3.errors.txt
new file mode 100644
index 00000000000..1b96db289dc
--- /dev/null
+++ b/tests/baselines/reference/classConstructorAccessibility3.errors.txt
@@ -0,0 +1,52 @@
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility3.ts(21,1): error TS2322: Type 'typeof Baz' is not assignable to type 'typeof Foo'.
+  Cannot assign a 'protected' constructor type to a 'public' constructor type.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility3.ts(22,1): error TS2322: Type 'typeof Qux' is not assignable to type 'typeof Foo'.
+  Cannot assign a 'private' constructor type to a 'public' constructor type.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility3.ts(28,1): error TS2322: Type 'typeof Qux' is not assignable to type 'typeof Baz'.
+  Cannot assign a 'private' constructor type to a 'protected' constructor type.
+
+
+==== tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility3.ts (3 errors) ====
+    
+    class Foo {
+         constructor(public x: number) { }
+    }
+    
+    class Bar {
+        public constructor(public x: number) { }
+    }
+    
+    class Baz {
+        protected constructor(public x: number) { }
+    }
+    
+    class Qux {
+         private constructor(public x: number) { }
+    }
+    
+    // b is public
+    let a = Foo;
+    a = Bar;
+    a = Baz; // error Baz is protected
+    ~
+!!! error TS2322: Type 'typeof Baz' is not assignable to type 'typeof Foo'.
+!!! error TS2322:   Cannot assign a 'protected' constructor type to a 'public' constructor type.
+    a = Qux; // error Qux is private
+    ~
+!!! error TS2322: Type 'typeof Qux' is not assignable to type 'typeof Foo'.
+!!! error TS2322:   Cannot assign a 'private' constructor type to a 'public' constructor type.
+    
+    // b is protected
+    let b = Baz;
+    b = Foo;
+    b = Bar;
+    b = Qux; // error Qux is private
+    ~
+!!! error TS2322: Type 'typeof Qux' is not assignable to type 'typeof Baz'.
+!!! error TS2322:   Cannot assign a 'private' constructor type to a 'protected' constructor type.
+    
+    // c is private
+    let c = Qux;
+    c = Foo;
+    c = Bar;
+    c = Baz;
\ No newline at end of file
diff --git a/tests/baselines/reference/classConstructorAccessibility3.js b/tests/baselines/reference/classConstructorAccessibility3.js
new file mode 100644
index 00000000000..acc7d38aa55
--- /dev/null
+++ b/tests/baselines/reference/classConstructorAccessibility3.js
@@ -0,0 +1,98 @@
+//// [classConstructorAccessibility3.ts]
+
+class Foo {
+     constructor(public x: number) { }
+}
+
+class Bar {
+    public constructor(public x: number) { }
+}
+
+class Baz {
+    protected constructor(public x: number) { }
+}
+
+class Qux {
+     private constructor(public x: number) { }
+}
+
+// b is public
+let a = Foo;
+a = Bar;
+a = Baz; // error Baz is protected
+a = Qux; // error Qux is private
+
+// b is protected
+let b = Baz;
+b = Foo;
+b = Bar;
+b = Qux; // error Qux is private
+
+// c is private
+let c = Qux;
+c = Foo;
+c = Bar;
+c = Baz;
+
+//// [classConstructorAccessibility3.js]
+var Foo = (function () {
+    function Foo(x) {
+        this.x = x;
+    }
+    return Foo;
+}());
+var Bar = (function () {
+    function Bar(x) {
+        this.x = x;
+    }
+    return Bar;
+}());
+var Baz = (function () {
+    function Baz(x) {
+        this.x = x;
+    }
+    return Baz;
+}());
+var Qux = (function () {
+    function Qux(x) {
+        this.x = x;
+    }
+    return Qux;
+}());
+// b is public
+var a = Foo;
+a = Bar;
+a = Baz; // error Baz is protected
+a = Qux; // error Qux is private
+// b is protected
+var b = Baz;
+b = Foo;
+b = Bar;
+b = Qux; // error Qux is private
+// c is private
+var c = Qux;
+c = Foo;
+c = Bar;
+c = Baz;
+
+
+//// [classConstructorAccessibility3.d.ts]
+declare class Foo {
+    x: number;
+    constructor(x: number);
+}
+declare class Bar {
+    x: number;
+    constructor(x: number);
+}
+declare class Baz {
+    x: number;
+    protected constructor(x: number);
+}
+declare class Qux {
+    x: number;
+    private constructor(x);
+}
+declare let a: typeof Foo;
+declare let b: typeof Baz;
+declare let c: typeof Qux;
diff --git a/tests/baselines/reference/classConstructorAccessibility4.js b/tests/baselines/reference/classConstructorAccessibility4.js
new file mode 100644
index 00000000000..6342facae21
--- /dev/null
+++ b/tests/baselines/reference/classConstructorAccessibility4.js
@@ -0,0 +1,93 @@
+//// [classConstructorAccessibility4.ts]
+
+class A {
+    private constructor() { }
+
+    method() {
+        class B {
+            method() {
+                new A(); // OK
+            }
+        }
+
+        class C extends A { // OK
+        }
+    }
+}
+
+class D {
+    protected constructor() { }
+
+    method() {
+        class E {
+            method() {
+                new D(); // OK
+            }
+        }
+
+        class F extends D { // OK
+        }
+    }
+}
+
+//// [classConstructorAccessibility4.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var A = (function () {
+    function A() {
+    }
+    A.prototype.method = function () {
+        var B = (function () {
+            function B() {
+            }
+            B.prototype.method = function () {
+                new A(); // OK
+            };
+            return B;
+        }());
+        var C = (function (_super) {
+            __extends(C, _super);
+            function C() {
+                _super.apply(this, arguments);
+            }
+            return C;
+        }(A));
+    };
+    return A;
+}());
+var D = (function () {
+    function D() {
+    }
+    D.prototype.method = function () {
+        var E = (function () {
+            function E() {
+            }
+            E.prototype.method = function () {
+                new D(); // OK
+            };
+            return E;
+        }());
+        var F = (function (_super) {
+            __extends(F, _super);
+            function F() {
+                _super.apply(this, arguments);
+            }
+            return F;
+        }(D));
+    };
+    return D;
+}());
+
+
+//// [classConstructorAccessibility4.d.ts]
+declare class A {
+    private constructor();
+    method(): void;
+}
+declare class D {
+    protected constructor();
+    method(): void;
+}
diff --git a/tests/baselines/reference/classConstructorAccessibility4.symbols b/tests/baselines/reference/classConstructorAccessibility4.symbols
new file mode 100644
index 00000000000..e3d8301ca68
--- /dev/null
+++ b/tests/baselines/reference/classConstructorAccessibility4.symbols
@@ -0,0 +1,53 @@
+=== tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility4.ts ===
+
+class A {
+>A : Symbol(A, Decl(classConstructorAccessibility4.ts, 0, 0))
+
+    private constructor() { }
+
+    method() {
+>method : Symbol(method, Decl(classConstructorAccessibility4.ts, 2, 29))
+
+        class B {
+>B : Symbol(B, Decl(classConstructorAccessibility4.ts, 4, 14))
+
+            method() {
+>method : Symbol(method, Decl(classConstructorAccessibility4.ts, 5, 17))
+
+                new A(); // OK
+>A : Symbol(A, Decl(classConstructorAccessibility4.ts, 0, 0))
+            }
+        }
+
+        class C extends A { // OK
+>C : Symbol(C, Decl(classConstructorAccessibility4.ts, 9, 9))
+>A : Symbol(A, Decl(classConstructorAccessibility4.ts, 0, 0))
+        }
+    }
+}
+
+class D {
+>D : Symbol(D, Decl(classConstructorAccessibility4.ts, 14, 1))
+
+    protected constructor() { }
+
+    method() {
+>method : Symbol(method, Decl(classConstructorAccessibility4.ts, 17, 31))
+
+        class E {
+>E : Symbol(E, Decl(classConstructorAccessibility4.ts, 19, 14))
+
+            method() {
+>method : Symbol(method, Decl(classConstructorAccessibility4.ts, 20, 17))
+
+                new D(); // OK
+>D : Symbol(D, Decl(classConstructorAccessibility4.ts, 14, 1))
+            }
+        }
+
+        class F extends D { // OK
+>F : Symbol(F, Decl(classConstructorAccessibility4.ts, 24, 9))
+>D : Symbol(D, Decl(classConstructorAccessibility4.ts, 14, 1))
+        }
+    }
+}
diff --git a/tests/baselines/reference/classConstructorAccessibility4.types b/tests/baselines/reference/classConstructorAccessibility4.types
new file mode 100644
index 00000000000..1eb5a25e220
--- /dev/null
+++ b/tests/baselines/reference/classConstructorAccessibility4.types
@@ -0,0 +1,55 @@
+=== tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility4.ts ===
+
+class A {
+>A : A
+
+    private constructor() { }
+
+    method() {
+>method : () => void
+
+        class B {
+>B : B
+
+            method() {
+>method : () => void
+
+                new A(); // OK
+>new A() : A
+>A : typeof A
+            }
+        }
+
+        class C extends A { // OK
+>C : C
+>A : A
+        }
+    }
+}
+
+class D {
+>D : D
+
+    protected constructor() { }
+
+    method() {
+>method : () => void
+
+        class E {
+>E : E
+
+            method() {
+>method : () => void
+
+                new D(); // OK
+>new D() : D
+>D : typeof D
+            }
+        }
+
+        class F extends D { // OK
+>F : F
+>D : D
+        }
+    }
+}
diff --git a/tests/baselines/reference/classConstructorOverloadsAccessibility.errors.txt b/tests/baselines/reference/classConstructorOverloadsAccessibility.errors.txt
new file mode 100644
index 00000000000..8882b9f0180
--- /dev/null
+++ b/tests/baselines/reference/classConstructorOverloadsAccessibility.errors.txt
@@ -0,0 +1,45 @@
+tests/cases/conformance/classes/constructorDeclarations/classConstructorOverloadsAccessibility.ts(3,2): error TS2385: Overload signatures must all be public, private or protected.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorOverloadsAccessibility.ts(4,2): error TS2385: Overload signatures must all be public, private or protected.
+tests/cases/conformance/classes/constructorDeclarations/classConstructorOverloadsAccessibility.ts(12,2): error TS2385: Overload signatures must all be public, private or protected.
+
+
+==== tests/cases/conformance/classes/constructorDeclarations/classConstructorOverloadsAccessibility.ts (3 errors) ====
+    
+    class A {
+    	public constructor(a: boolean) // error
+    	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2385: Overload signatures must all be public, private or protected.
+    	protected constructor(a: number) // error
+    	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2385: Overload signatures must all be public, private or protected.
+    	private constructor(a: string)
+    	private constructor() { 
+    		
+    	}
+    }
+    
+    class B {
+    	protected constructor(a: number) // error
+    	~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2385: Overload signatures must all be public, private or protected.
+    	constructor(a: string)
+    	constructor() { 
+    		
+    	}
+    }
+    
+    class C {
+    	protected constructor(a: number)
+    	protected constructor(a: string)
+    	protected constructor() { 
+    		
+    	}
+    }
+    
+    class D {
+    	constructor(a: number)
+    	constructor(a: string)
+    	public constructor() { 
+    		
+    	}
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/classConstructorOverloadsAccessibility.js b/tests/baselines/reference/classConstructorOverloadsAccessibility.js
new file mode 100644
index 00000000000..3914c29b785
--- /dev/null
+++ b/tests/baselines/reference/classConstructorOverloadsAccessibility.js
@@ -0,0 +1,76 @@
+//// [classConstructorOverloadsAccessibility.ts]
+
+class A {
+	public constructor(a: boolean) // error
+	protected constructor(a: number) // error
+	private constructor(a: string)
+	private constructor() { 
+		
+	}
+}
+
+class B {
+	protected constructor(a: number) // error
+	constructor(a: string)
+	constructor() { 
+		
+	}
+}
+
+class C {
+	protected constructor(a: number)
+	protected constructor(a: string)
+	protected constructor() { 
+		
+	}
+}
+
+class D {
+	constructor(a: number)
+	constructor(a: string)
+	public constructor() { 
+		
+	}
+}
+
+//// [classConstructorOverloadsAccessibility.js]
+var A = (function () {
+    function A() {
+    }
+    return A;
+}());
+var B = (function () {
+    function B() {
+    }
+    return B;
+}());
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+var D = (function () {
+    function D() {
+    }
+    return D;
+}());
+
+
+//// [classConstructorOverloadsAccessibility.d.ts]
+declare class A {
+    constructor(a: boolean);
+    protected constructor(a: number);
+    private constructor(a);
+}
+declare class B {
+    protected constructor(a: number);
+    constructor(a: string);
+}
+declare class C {
+    protected constructor(a: number);
+    protected constructor(a: string);
+}
+declare class D {
+    constructor(a: number);
+    constructor(a: string);
+}
diff --git a/tests/baselines/reference/classExtendsNull.errors.txt b/tests/baselines/reference/classExtendsNull.errors.txt
index 7bb44774826..905c90c42fd 100644
--- a/tests/baselines/reference/classExtendsNull.errors.txt
+++ b/tests/baselines/reference/classExtendsNull.errors.txt
@@ -1,17 +1,14 @@
-tests/cases/compiler/classExtendsNull.ts(2,5): error TS17005: A constructor cannot contain a 'super' call when its class extends 'null'
+tests/cases/compiler/classExtendsNull.ts(3,9): error TS17005: A constructor cannot contain a 'super' call when its class extends 'null'
 
 
 ==== tests/cases/compiler/classExtendsNull.ts (1 errors) ====
     class C extends null {
         constructor() {
-        ~~~~~~~~~~~~~~~
             super();
-    ~~~~~~~~~~~~~~~~
-            return Object.create(null);
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-        }
-    ~~~~~
+            ~~~~~~~
 !!! error TS17005: A constructor cannot contain a 'super' call when its class extends 'null'
+            return Object.create(null);
+        }
     }
     
     class D extends null {
diff --git a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt
index fe608b14379..2efaf2e5ae2 100644
--- a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt
+++ b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt
@@ -1,70 +1,54 @@
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(26,12): error TS2365: Operator '<' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(27,12): error TS2365: Operator '<' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(28,12): error TS2365: Operator '<' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(29,12): error TS2365: Operator '<' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(31,12): error TS2365: Operator '<' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(32,12): error TS2365: Operator '<' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(33,12): error TS2365: Operator '<' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(34,12): error TS2365: Operator '<' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(37,12): error TS2365: Operator '>' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(38,12): error TS2365: Operator '>' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(39,12): error TS2365: Operator '>' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(40,12): error TS2365: Operator '>' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(42,12): error TS2365: Operator '>' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(43,12): error TS2365: Operator '>' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(44,12): error TS2365: Operator '>' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(45,12): error TS2365: Operator '>' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(48,12): error TS2365: Operator '<=' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(49,12): error TS2365: Operator '<=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(50,12): error TS2365: Operator '<=' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(51,12): error TS2365: Operator '<=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(53,12): error TS2365: Operator '<=' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(54,12): error TS2365: Operator '<=' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(55,12): error TS2365: Operator '<=' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(56,12): error TS2365: Operator '<=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(59,12): error TS2365: Operator '>=' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(60,12): error TS2365: Operator '>=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(61,12): error TS2365: Operator '>=' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(62,12): error TS2365: Operator '>=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(64,12): error TS2365: Operator '>=' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(65,12): error TS2365: Operator '>=' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(66,12): error TS2365: Operator '>=' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(67,12): error TS2365: Operator '>=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(70,12): error TS2365: Operator '==' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(71,12): error TS2365: Operator '==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(72,12): error TS2365: Operator '==' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(73,12): error TS2365: Operator '==' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(75,12): error TS2365: Operator '==' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(76,12): error TS2365: Operator '==' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(77,12): error TS2365: Operator '==' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(78,12): error TS2365: Operator '==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(81,12): error TS2365: Operator '!=' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(82,12): error TS2365: Operator '!=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(83,12): error TS2365: Operator '!=' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(84,12): error TS2365: Operator '!=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(86,12): error TS2365: Operator '!=' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(87,12): error TS2365: Operator '!=' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(88,12): error TS2365: Operator '!=' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(89,12): error TS2365: Operator '!=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(92,12): error TS2365: Operator '===' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(93,12): error TS2365: Operator '===' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(94,12): error TS2365: Operator '===' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(95,12): error TS2365: Operator '===' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(97,12): error TS2365: Operator '===' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(98,12): error TS2365: Operator '===' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(99,12): error TS2365: Operator '===' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(100,12): error TS2365: Operator '===' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(103,12): error TS2365: Operator '!==' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(104,12): error TS2365: Operator '!==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(105,12): error TS2365: Operator '!==' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(106,12): error TS2365: Operator '!==' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(108,12): error TS2365: Operator '!==' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(109,12): error TS2365: Operator '!==' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
 tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(110,12): error TS2365: Operator '!==' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(111,12): error TS2365: Operator '!==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
 
 
-==== tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts (64 errors) ====
+==== tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts (48 errors) ====
     class Base {
         public a: string;
     }
@@ -100,8 +84,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~
 !!! error TS2365: Operator '<' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r1a4 = a4 < b4;
-               ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r1b1 = b1 < a1;
                ~~~~~~~
@@ -113,8 +95,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~
 !!! error TS2365: Operator '<' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
     var r1b4 = b4 < a4;
-               ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator >
     var r2a1 = a1 > b1;
@@ -127,8 +107,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~
 !!! error TS2365: Operator '>' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r2a4 = a4 > b4;
-               ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r2b1 = b1 > a1;
                ~~~~~~~
@@ -140,8 +118,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~
 !!! error TS2365: Operator '>' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
     var r2b4 = b4 > a4;
-               ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator <=
     var r3a1 = a1 <= b1;
@@ -154,8 +130,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '<=' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r3a4 = a4 <= b4;
-               ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r3b1 = b1 <= a1;
                ~~~~~~~~
@@ -167,8 +141,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '<=' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
     var r3b4 = b4 <= a4;
-               ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator >=
     var r4a1 = a1 >= b1;
@@ -181,8 +153,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '>=' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r4a4 = a4 >= b4;
-               ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r4b1 = b1 >= a1;
                ~~~~~~~~
@@ -194,8 +164,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '>=' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
     var r4b4 = b4 >= a4;
-               ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator ==
     var r5a1 = a1 == b1;
@@ -208,8 +176,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '==' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r5a4 = a4 == b4;
-               ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r5b1 = b1 == a1;
                ~~~~~~~~
@@ -221,8 +187,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '==' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
     var r5b4 = b4 == a4;
-               ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator !=
     var r6a1 = a1 != b1;
@@ -235,8 +199,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '!=' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r6a4 = a4 != b4;
-               ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r6b1 = b1 != a1;
                ~~~~~~~~
@@ -248,8 +210,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~
 !!! error TS2365: Operator '!=' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
     var r6b4 = b4 != a4;
-               ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator ===
     var r7a1 = a1 === b1;
@@ -262,8 +222,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~~
 !!! error TS2365: Operator '===' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r7a4 = a4 === b4;
-               ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r7b1 = b1 === a1;
                ~~~~~~~~~
@@ -275,8 +233,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~~
 !!! error TS2365: Operator '===' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
     var r7b4 = b4 === a4;
-               ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator !==
     var r8a1 = a1 !== b1;
@@ -289,8 +245,6 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
                ~~~~~~~~~
 !!! error TS2365: Operator '!==' cannot be applied to types '{ [index: number]: Base; }' and '{ [index: number]: C; }'.
     var r8a4 = a4 !== b4;
-               ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r8b1 = b1 !== a1;
                ~~~~~~~~~
@@ -301,6 +255,4 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
     var r8b3 = b3 !== a3;
                ~~~~~~~~~
 !!! error TS2365: Operator '!==' cannot be applied to types '{ [index: number]: C; }' and '{ [index: number]: Base; }'.
-    var r8b4 = b4 !== a4;
-               ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
\ No newline at end of file
+    var r8b4 = b4 !== a4;
\ No newline at end of file
diff --git a/tests/baselines/reference/compoundAdditionAssignmentLHSCanBeAssigned.types b/tests/baselines/reference/compoundAdditionAssignmentLHSCanBeAssigned.types
index 92835611c6d..e40422450b4 100644
--- a/tests/baselines/reference/compoundAdditionAssignmentLHSCanBeAssigned.types
+++ b/tests/baselines/reference/compoundAdditionAssignmentLHSCanBeAssigned.types
@@ -98,7 +98,7 @@ x2 += E.a;
 x2 += {};
 >x2 += {} : string
 >x2 : string
->{} : { [x: number]: undefined; }
+>{} : {}
 
 x2 += null;
 >x2 += null : string
diff --git a/tests/baselines/reference/computedPropertyNames10_ES5.types b/tests/baselines/reference/computedPropertyNames10_ES5.types
index 9dea9cfca93..b9d999397ab 100644
--- a/tests/baselines/reference/computedPropertyNames10_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames10_ES5.types
@@ -9,8 +9,8 @@ var a: any;
 >a : any
 
 var v = {
->v : { [0](): void; [""](): void; }
->{    [s]() { },    [n]() { },    [s + s]() { },    [s + n]() { },    [+s]() { },    [""]() { },    [0]() { },    [a]() { },    [<any>true]() { },    [`hello bye`]() { },    [`hello ${a} bye`]() { }} : { [0](): void; [""](): void; }
+>v : { [x: string]: () => void; [x: number]: () => void; [0](): void; [""](): void; }
+>{    [s]() { },    [n]() { },    [s + s]() { },    [s + n]() { },    [+s]() { },    [""]() { },    [0]() { },    [a]() { },    [<any>true]() { },    [`hello bye`]() { },    [`hello ${a} bye`]() { }} : { [x: string]: () => void; [x: number]: () => void; [0](): void; [""](): void; }
 
     [s]() { },
 >s : string
diff --git a/tests/baselines/reference/computedPropertyNames10_ES6.types b/tests/baselines/reference/computedPropertyNames10_ES6.types
index d2faa138980..1883febb39b 100644
--- a/tests/baselines/reference/computedPropertyNames10_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames10_ES6.types
@@ -9,8 +9,8 @@ var a: any;
 >a : any
 
 var v = {
->v : { [0](): void; [""](): void; }
->{    [s]() { },    [n]() { },    [s + s]() { },    [s + n]() { },    [+s]() { },    [""]() { },    [0]() { },    [a]() { },    [<any>true]() { },    [`hello bye`]() { },    [`hello ${a} bye`]() { }} : { [0](): void; [""](): void; }
+>v : { [x: string]: () => void; [x: number]: () => void; [0](): void; [""](): void; }
+>{    [s]() { },    [n]() { },    [s + s]() { },    [s + n]() { },    [+s]() { },    [""]() { },    [0]() { },    [a]() { },    [<any>true]() { },    [`hello bye`]() { },    [`hello ${a} bye`]() { }} : { [x: string]: () => void; [x: number]: () => void; [0](): void; [""](): void; }
 
     [s]() { },
 >s : string
diff --git a/tests/baselines/reference/computedPropertyNames11_ES5.types b/tests/baselines/reference/computedPropertyNames11_ES5.types
index ae626ec3cba..e15b46cc6c1 100644
--- a/tests/baselines/reference/computedPropertyNames11_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames11_ES5.types
@@ -9,8 +9,8 @@ var a: any;
 >a : any
 
 var v = {
->v : { readonly [0]: number; [""]: any; }
->{    get [s]() { return 0; },    set [n](v) { },    get [s + s]() { return 0; },    set [s + n](v) { },    get [+s]() { return 0; },    set [""](v) { },    get [0]() { return 0; },    set [a](v) { },    get [<any>true]() { return 0; },    set [`hello bye`](v) { },    get [`hello ${a} bye`]() { return 0; }} : { readonly [0]: number; [""]: any; }
+>v : { [x: string]: any; [x: number]: any; readonly [0]: number; [""]: any; }
+>{    get [s]() { return 0; },    set [n](v) { },    get [s + s]() { return 0; },    set [s + n](v) { },    get [+s]() { return 0; },    set [""](v) { },    get [0]() { return 0; },    set [a](v) { },    get [<any>true]() { return 0; },    set [`hello bye`](v) { },    get [`hello ${a} bye`]() { return 0; }} : { [x: string]: any; [x: number]: any; readonly [0]: number; [""]: any; }
 
     get [s]() { return 0; },
 >s : string
diff --git a/tests/baselines/reference/computedPropertyNames11_ES6.types b/tests/baselines/reference/computedPropertyNames11_ES6.types
index 06dc26e9843..eb5fc105a7a 100644
--- a/tests/baselines/reference/computedPropertyNames11_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames11_ES6.types
@@ -9,8 +9,8 @@ var a: any;
 >a : any
 
 var v = {
->v : { readonly [0]: number; [""]: any; }
->{    get [s]() { return 0; },    set [n](v) { },    get [s + s]() { return 0; },    set [s + n](v) { },    get [+s]() { return 0; },    set [""](v) { },    get [0]() { return 0; },    set [a](v) { },    get [<any>true]() { return 0; },    set [`hello bye`](v) { },    get [`hello ${a} bye`]() { return 0; }} : { readonly [0]: number; [""]: any; }
+>v : { [x: string]: any; [x: number]: any; readonly [0]: number; [""]: any; }
+>{    get [s]() { return 0; },    set [n](v) { },    get [s + s]() { return 0; },    set [s + n](v) { },    get [+s]() { return 0; },    set [""](v) { },    get [0]() { return 0; },    set [a](v) { },    get [<any>true]() { return 0; },    set [`hello bye`](v) { },    get [`hello ${a} bye`]() { return 0; }} : { [x: string]: any; [x: number]: any; readonly [0]: number; [""]: any; }
 
     get [s]() { return 0; },
 >s : string
diff --git a/tests/baselines/reference/computedPropertyNames18_ES5.types b/tests/baselines/reference/computedPropertyNames18_ES5.types
index c60ab32d3f8..d6808a8edc0 100644
--- a/tests/baselines/reference/computedPropertyNames18_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames18_ES5.types
@@ -3,8 +3,8 @@ function foo() {
 >foo : () => void
 
     var obj = {
->obj : {}
->{        [this.bar]: 0    } : {}
+>obj : { [x: number]: number; }
+>{        [this.bar]: 0    } : { [x: number]: number; }
 
         [this.bar]: 0
 >this.bar : any
diff --git a/tests/baselines/reference/computedPropertyNames18_ES6.types b/tests/baselines/reference/computedPropertyNames18_ES6.types
index 33a15b6c5a9..11d58e48c69 100644
--- a/tests/baselines/reference/computedPropertyNames18_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames18_ES6.types
@@ -3,8 +3,8 @@ function foo() {
 >foo : () => void
 
     var obj = {
->obj : {}
->{        [this.bar]: 0    } : {}
+>obj : { [x: number]: number; }
+>{        [this.bar]: 0    } : { [x: number]: number; }
 
         [this.bar]: 0
 >this.bar : any
diff --git a/tests/baselines/reference/computedPropertyNames1_ES5.types b/tests/baselines/reference/computedPropertyNames1_ES5.types
index 6c94c846f30..bcff3b34177 100644
--- a/tests/baselines/reference/computedPropertyNames1_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames1_ES5.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNames1_ES5.ts ===
 var v = {
->v : {}
->{    get [0 + 1]() { return 0 },    set [0 + 1](v: string) { } //No error} : {}
+>v : { [x: number]: number | string; }
+>{    get [0 + 1]() { return 0 },    set [0 + 1](v: string) { } //No error} : { [x: number]: number | string; }
 
     get [0 + 1]() { return 0 },
 >0 + 1 : number
diff --git a/tests/baselines/reference/computedPropertyNames1_ES6.types b/tests/baselines/reference/computedPropertyNames1_ES6.types
index 95e5a011ea2..df2237a463f 100644
--- a/tests/baselines/reference/computedPropertyNames1_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames1_ES6.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNames1_ES6.ts ===
 var v = {
->v : {}
->{    get [0 + 1]() { return 0 },    set [0 + 1](v: string) { } //No error} : {}
+>v : { [x: number]: number | string; }
+>{    get [0 + 1]() { return 0 },    set [0 + 1](v: string) { } //No error} : { [x: number]: number | string; }
 
     get [0 + 1]() { return 0 },
 >0 + 1 : number
diff --git a/tests/baselines/reference/computedPropertyNames20_ES5.types b/tests/baselines/reference/computedPropertyNames20_ES5.types
index 91cc2c42963..65ee55be379 100644
--- a/tests/baselines/reference/computedPropertyNames20_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames20_ES5.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNames20_ES5.ts ===
 var obj = {
->obj : {}
->{    [this.bar]: 0} : {}
+>obj : { [x: number]: number; }
+>{    [this.bar]: 0} : { [x: number]: number; }
 
     [this.bar]: 0
 >this.bar : any
diff --git a/tests/baselines/reference/computedPropertyNames20_ES6.types b/tests/baselines/reference/computedPropertyNames20_ES6.types
index 4ef6f675cce..91e5c8d7843 100644
--- a/tests/baselines/reference/computedPropertyNames20_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames20_ES6.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNames20_ES6.ts ===
 var obj = {
->obj : {}
->{    [this.bar]: 0} : {}
+>obj : { [x: number]: number; }
+>{    [this.bar]: 0} : { [x: number]: number; }
 
     [this.bar]: 0
 >this.bar : any
diff --git a/tests/baselines/reference/computedPropertyNames22_ES5.types b/tests/baselines/reference/computedPropertyNames22_ES5.types
index ca59250825c..eeec22d2e61 100644
--- a/tests/baselines/reference/computedPropertyNames22_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames22_ES5.types
@@ -6,8 +6,8 @@ class C {
 >bar : () => number
 
         var obj = {
->obj : {}
->{            [this.bar()]() { }        } : {}
+>obj : { [x: number]: () => void; }
+>{            [this.bar()]() { }        } : { [x: number]: () => void; }
 
             [this.bar()]() { }
 >this.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames22_ES6.types b/tests/baselines/reference/computedPropertyNames22_ES6.types
index d5fbce29f7d..af9ef9d3a31 100644
--- a/tests/baselines/reference/computedPropertyNames22_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames22_ES6.types
@@ -6,8 +6,8 @@ class C {
 >bar : () => number
 
         var obj = {
->obj : {}
->{            [this.bar()]() { }        } : {}
+>obj : { [x: number]: () => void; }
+>{            [this.bar()]() { }        } : { [x: number]: () => void; }
 
             [this.bar()]() { }
 >this.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames25_ES5.types b/tests/baselines/reference/computedPropertyNames25_ES5.types
index 6ca67cce410..f1acc296709 100644
--- a/tests/baselines/reference/computedPropertyNames25_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames25_ES5.types
@@ -17,8 +17,8 @@ class C extends Base {
 >foo : () => number
 
         var obj = {
->obj : {}
->{            [super.bar()]() { }        } : {}
+>obj : { [x: number]: () => void; }
+>{            [super.bar()]() { }        } : { [x: number]: () => void; }
 
             [super.bar()]() { }
 >super.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames25_ES6.types b/tests/baselines/reference/computedPropertyNames25_ES6.types
index 1c093ebc59f..26c38013906 100644
--- a/tests/baselines/reference/computedPropertyNames25_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames25_ES6.types
@@ -17,8 +17,8 @@ class C extends Base {
 >foo : () => number
 
         var obj = {
->obj : {}
->{            [super.bar()]() { }        } : {}
+>obj : { [x: number]: () => void; }
+>{            [super.bar()]() { }        } : { [x: number]: () => void; }
 
             [super.bar()]() { }
 >super.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames28_ES5.types b/tests/baselines/reference/computedPropertyNames28_ES5.types
index 273dcd426d8..89a2a7ac017 100644
--- a/tests/baselines/reference/computedPropertyNames28_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames28_ES5.types
@@ -12,8 +12,8 @@ class C extends Base {
 >super : typeof Base
 
         var obj = {
->obj : {}
->{            [(super(), "prop")]() { }        } : {}
+>obj : { [x: string]: () => void; }
+>{            [(super(), "prop")]() { }        } : { [x: string]: () => void; }
 
             [(super(), "prop")]() { }
 >(super(), "prop") : string
diff --git a/tests/baselines/reference/computedPropertyNames28_ES6.types b/tests/baselines/reference/computedPropertyNames28_ES6.types
index a34fb33f6c7..df020c9a5ff 100644
--- a/tests/baselines/reference/computedPropertyNames28_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames28_ES6.types
@@ -12,8 +12,8 @@ class C extends Base {
 >super : typeof Base
 
         var obj = {
->obj : {}
->{            [(super(), "prop")]() { }        } : {}
+>obj : { [x: string]: () => void; }
+>{            [(super(), "prop")]() { }        } : { [x: string]: () => void; }
 
             [(super(), "prop")]() { }
 >(super(), "prop") : string
diff --git a/tests/baselines/reference/computedPropertyNames29_ES5.types b/tests/baselines/reference/computedPropertyNames29_ES5.types
index f3448f10857..d2f89ef6b18 100644
--- a/tests/baselines/reference/computedPropertyNames29_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames29_ES5.types
@@ -9,8 +9,8 @@ class C {
 >() => {            var obj = {                [this.bar()]() { } // needs capture            };        } : () => void
 
             var obj = {
->obj : {}
->{                [this.bar()]() { } // needs capture            } : {}
+>obj : { [x: number]: () => void; }
+>{                [this.bar()]() { } // needs capture            } : { [x: number]: () => void; }
 
                 [this.bar()]() { } // needs capture
 >this.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames29_ES6.types b/tests/baselines/reference/computedPropertyNames29_ES6.types
index cd01d37556a..bb324b2b382 100644
--- a/tests/baselines/reference/computedPropertyNames29_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames29_ES6.types
@@ -9,8 +9,8 @@ class C {
 >() => {            var obj = {                [this.bar()]() { } // needs capture            };        } : () => void
 
             var obj = {
->obj : {}
->{                [this.bar()]() { } // needs capture            } : {}
+>obj : { [x: number]: () => void; }
+>{                [this.bar()]() { } // needs capture            } : { [x: number]: () => void; }
 
                 [this.bar()]() { } // needs capture
 >this.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames31_ES5.types b/tests/baselines/reference/computedPropertyNames31_ES5.types
index 6c0f2572a06..832b2bc067a 100644
--- a/tests/baselines/reference/computedPropertyNames31_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames31_ES5.types
@@ -20,8 +20,8 @@ class C extends Base {
 >() => {            var obj = {                [super.bar()]() { } // needs capture            };        } : () => void
 
             var obj = {
->obj : {}
->{                [super.bar()]() { } // needs capture            } : {}
+>obj : { [x: number]: () => void; }
+>{                [super.bar()]() { } // needs capture            } : { [x: number]: () => void; }
 
                 [super.bar()]() { } // needs capture
 >super.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames31_ES6.types b/tests/baselines/reference/computedPropertyNames31_ES6.types
index eaddc036812..4f59b1e8c6d 100644
--- a/tests/baselines/reference/computedPropertyNames31_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames31_ES6.types
@@ -20,8 +20,8 @@ class C extends Base {
 >() => {            var obj = {                [super.bar()]() { } // needs capture            };        } : () => void
 
             var obj = {
->obj : {}
->{                [super.bar()]() { } // needs capture            } : {}
+>obj : { [x: number]: () => void; }
+>{                [super.bar()]() { } // needs capture            } : { [x: number]: () => void; }
 
                 [super.bar()]() { } // needs capture
 >super.bar() : number
diff --git a/tests/baselines/reference/computedPropertyNames33_ES5.types b/tests/baselines/reference/computedPropertyNames33_ES5.types
index f44ac3ca769..7031981481f 100644
--- a/tests/baselines/reference/computedPropertyNames33_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames33_ES5.types
@@ -12,8 +12,8 @@ class C<T> {
 >bar : () => number
 
         var obj = {
->obj : {}
->{            [foo<T>()]() { }        } : {}
+>obj : { [x: string]: () => void; }
+>{            [foo<T>()]() { }        } : { [x: string]: () => void; }
 
             [foo<T>()]() { }
 >foo<T>() : string
diff --git a/tests/baselines/reference/computedPropertyNames33_ES6.types b/tests/baselines/reference/computedPropertyNames33_ES6.types
index 3081337c8bb..3c57daf2ace 100644
--- a/tests/baselines/reference/computedPropertyNames33_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames33_ES6.types
@@ -12,8 +12,8 @@ class C<T> {
 >bar : () => number
 
         var obj = {
->obj : {}
->{            [foo<T>()]() { }        } : {}
+>obj : { [x: string]: () => void; }
+>{            [foo<T>()]() { }        } : { [x: string]: () => void; }
 
             [foo<T>()]() { }
 >foo<T>() : string
diff --git a/tests/baselines/reference/computedPropertyNames46_ES5.types b/tests/baselines/reference/computedPropertyNames46_ES5.types
index 394b22bd904..b8df0d56e13 100644
--- a/tests/baselines/reference/computedPropertyNames46_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames46_ES5.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNames46_ES5.ts ===
 var o = {
->o : {}
->{    ["" || 0]: 0} : {}
+>o : { [x: string]: number; }
+>{    ["" || 0]: 0} : { [x: string]: number; }
 
     ["" || 0]: 0
 >"" || 0 : string | number
diff --git a/tests/baselines/reference/computedPropertyNames46_ES6.types b/tests/baselines/reference/computedPropertyNames46_ES6.types
index 864fd81321d..a786eca200c 100644
--- a/tests/baselines/reference/computedPropertyNames46_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames46_ES6.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNames46_ES6.ts ===
 var o = {
->o : {}
->{    ["" || 0]: 0} : {}
+>o : { [x: string]: number; }
+>{    ["" || 0]: 0} : { [x: string]: number; }
 
     ["" || 0]: 0
 >"" || 0 : string | number
diff --git a/tests/baselines/reference/computedPropertyNames47_ES5.types b/tests/baselines/reference/computedPropertyNames47_ES5.types
index 6aa841ffd62..cdc2c3301f6 100644
--- a/tests/baselines/reference/computedPropertyNames47_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames47_ES5.types
@@ -8,8 +8,8 @@ enum E2 { x }
 >x : E2
 
 var o = {
->o : {}
->{    [E1.x || E2.x]: 0} : {}
+>o : { [x: number]: number; }
+>{    [E1.x || E2.x]: 0} : { [x: number]: number; }
 
     [E1.x || E2.x]: 0
 >E1.x || E2.x : E1 | E2
diff --git a/tests/baselines/reference/computedPropertyNames47_ES6.types b/tests/baselines/reference/computedPropertyNames47_ES6.types
index f038b172ca1..a923e934d66 100644
--- a/tests/baselines/reference/computedPropertyNames47_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames47_ES6.types
@@ -8,8 +8,8 @@ enum E2 { x }
 >x : E2
 
 var o = {
->o : {}
->{    [E1.x || E2.x]: 0} : {}
+>o : { [x: number]: number; }
+>{    [E1.x || E2.x]: 0} : { [x: number]: number; }
 
     [E1.x || E2.x]: 0
 >E1.x || E2.x : E1 | E2
diff --git a/tests/baselines/reference/computedPropertyNames48_ES5.types b/tests/baselines/reference/computedPropertyNames48_ES5.types
index 2b9131a11c8..12752d8abeb 100644
--- a/tests/baselines/reference/computedPropertyNames48_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames48_ES5.types
@@ -39,9 +39,9 @@ extractIndexer({
 }); // Should return string
 
 extractIndexer({
->extractIndexer({    ["" || 0]: ""}) : any
+>extractIndexer({    ["" || 0]: ""}) : string
 >extractIndexer : <T>(p: { [n: number]: T; }) => T
->{    ["" || 0]: ""} : { [x: number]: undefined; }
+>{    ["" || 0]: ""} : { [x: string]: string; }
 
     ["" || 0]: ""
 >"" || 0 : string | number
diff --git a/tests/baselines/reference/computedPropertyNames48_ES6.types b/tests/baselines/reference/computedPropertyNames48_ES6.types
index 2b803b19bd6..832bc3c7025 100644
--- a/tests/baselines/reference/computedPropertyNames48_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames48_ES6.types
@@ -39,9 +39,9 @@ extractIndexer({
 }); // Should return string
 
 extractIndexer({
->extractIndexer({    ["" || 0]: ""}) : any
+>extractIndexer({    ["" || 0]: ""}) : string
 >extractIndexer : <T>(p: { [n: number]: T; }) => T
->{    ["" || 0]: ""} : { [x: number]: undefined; }
+>{    ["" || 0]: ""} : { [x: string]: string; }
 
     ["" || 0]: ""
 >"" || 0 : string | number
diff --git a/tests/baselines/reference/computedPropertyNames4_ES5.types b/tests/baselines/reference/computedPropertyNames4_ES5.types
index 6984d2e69b8..3c5f884640f 100644
--- a/tests/baselines/reference/computedPropertyNames4_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames4_ES5.types
@@ -9,8 +9,8 @@ var a: any;
 >a : any
 
 var v = {
->v : { [0]: number; [""]: number; }
->{    [s]: 0,    [n]: n,    [s + s]: 1,    [s + n]: 2,    [+s]: s,    [""]: 0,    [0]: 0,    [a]: 1,    [<any>true]: 0,    [`hello bye`]: 0,    [`hello ${a} bye`]: 0} : { [0]: number; [""]: number; }
+>v : { [x: string]: number | string; [x: number]: number | string; [0]: number; [""]: number; }
+>{    [s]: 0,    [n]: n,    [s + s]: 1,    [s + n]: 2,    [+s]: s,    [""]: 0,    [0]: 0,    [a]: 1,    [<any>true]: 0,    [`hello bye`]: 0,    [`hello ${a} bye`]: 0} : { [x: string]: number | string; [x: number]: number | string; [0]: number; [""]: number; }
 
     [s]: 0,
 >s : string
diff --git a/tests/baselines/reference/computedPropertyNames4_ES6.types b/tests/baselines/reference/computedPropertyNames4_ES6.types
index 1fece561f5a..335c2415bd0 100644
--- a/tests/baselines/reference/computedPropertyNames4_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames4_ES6.types
@@ -9,8 +9,8 @@ var a: any;
 >a : any
 
 var v = {
->v : { [0]: number; [""]: number; }
->{    [s]: 0,    [n]: n,    [s + s]: 1,    [s + n]: 2,    [+s]: s,    [""]: 0,    [0]: 0,    [a]: 1,    [<any>true]: 0,    [`hello bye`]: 0,    [`hello ${a} bye`]: 0} : { [0]: number; [""]: number; }
+>v : { [x: string]: number | string; [x: number]: number | string; [0]: number; [""]: number; }
+>{    [s]: 0,    [n]: n,    [s + s]: 1,    [s + n]: 2,    [+s]: s,    [""]: 0,    [0]: 0,    [a]: 1,    [<any>true]: 0,    [`hello bye`]: 0,    [`hello ${a} bye`]: 0} : { [x: string]: number | string; [x: number]: number | string; [0]: number; [""]: number; }
 
     [s]: 0,
 >s : string
diff --git a/tests/baselines/reference/computedPropertyNames7_ES5.types b/tests/baselines/reference/computedPropertyNames7_ES5.types
index 8ebd4d75668..3411198b590 100644
--- a/tests/baselines/reference/computedPropertyNames7_ES5.types
+++ b/tests/baselines/reference/computedPropertyNames7_ES5.types
@@ -6,8 +6,8 @@ enum E {
 >member : E
 }
 var v = {
->v : {}
->{    [E.member]: 0} : {}
+>v : { [x: number]: number; }
+>{    [E.member]: 0} : { [x: number]: number; }
 
     [E.member]: 0
 >E.member : E
diff --git a/tests/baselines/reference/computedPropertyNames7_ES6.types b/tests/baselines/reference/computedPropertyNames7_ES6.types
index 3a78b9c0ec6..eb72d546dbc 100644
--- a/tests/baselines/reference/computedPropertyNames7_ES6.types
+++ b/tests/baselines/reference/computedPropertyNames7_ES6.types
@@ -6,8 +6,8 @@ enum E {
 >member : E
 }
 var v = {
->v : {}
->{    [E.member]: 0} : {}
+>v : { [x: number]: number; }
+>{    [E.member]: 0} : { [x: number]: number; }
 
     [E.member]: 0
 >E.member : E
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType1_ES5.types b/tests/baselines/reference/computedPropertyNamesContextualType1_ES5.types
index bea7267d7d1..09cad594624 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType1_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType1_ES5.types
@@ -14,7 +14,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    ["" + 0](y) { return y.length; },    ["" + 1]: y => y.length} : { [x: string]: (y: string) => number; [x: number]: undefined; }
+>{    ["" + 0](y) { return y.length; },    ["" + 1]: y => y.length} : { [x: string]: (y: string) => number; }
 
     ["" + 0](y) { return y.length; },
 >"" + 0 : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType1_ES6.types b/tests/baselines/reference/computedPropertyNamesContextualType1_ES6.types
index c8d0be6e833..d9e9970ebec 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType1_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType1_ES6.types
@@ -14,7 +14,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    ["" + 0](y) { return y.length; },    ["" + 1]: y => y.length} : { [x: string]: (y: string) => number; [x: number]: undefined; }
+>{    ["" + 0](y) { return y.length; },    ["" + 1]: y => y.length} : { [x: string]: (y: string) => number; }
 
     ["" + 0](y) { return y.length; },
 >"" + 0 : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType2_ES5.types b/tests/baselines/reference/computedPropertyNamesContextualType2_ES5.types
index 52de216b803..5a5c48f2536 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType2_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType2_ES5.types
@@ -14,7 +14,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: string]: (y: string) => number; [x: number]: (y: string) => number; }
+>{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: number]: (y: string) => number; }
 
     [+"foo"](y) { return y.length; },
 >+"foo" : number
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType2_ES6.types b/tests/baselines/reference/computedPropertyNamesContextualType2_ES6.types
index cbbe0edc6a1..330351790ca 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType2_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType2_ES6.types
@@ -14,7 +14,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: string]: (y: string) => number; [x: number]: (y: string) => number; }
+>{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: number]: (y: string) => number; }
 
     [+"foo"](y) { return y.length; },
 >+"foo" : number
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType3_ES5.types b/tests/baselines/reference/computedPropertyNamesContextualType3_ES5.types
index 5f647fb4c1b..faff27c9154 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType3_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType3_ES5.types
@@ -10,7 +10,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: string]: (y: string) => number; }
+>{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: number]: (y: string) => number; }
 
     [+"foo"](y) { return y.length; },
 >+"foo" : number
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType3_ES6.types b/tests/baselines/reference/computedPropertyNamesContextualType3_ES6.types
index e872df6f1b2..18c32957944 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType3_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType3_ES6.types
@@ -10,7 +10,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: string]: (y: string) => number; }
+>{    [+"foo"](y) { return y.length; },    [+"bar"]: y => y.length} : { [x: number]: (y: string) => number; }
 
     [+"foo"](y) { return y.length; },
 >+"foo" : number
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType4_ES5.types b/tests/baselines/reference/computedPropertyNamesContextualType4_ES5.types
index e5a57363ca0..6f75f1a3633 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType4_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType4_ES5.types
@@ -12,7 +12,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [""+"foo"]: "",    [""+"bar"]: 0} : { [x: string]: string | number; [x: number]: undefined; }
+>{    [""+"foo"]: "",    [""+"bar"]: 0} : { [x: string]: string | number; }
 
     [""+"foo"]: "",
 >""+"foo" : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType4_ES6.types b/tests/baselines/reference/computedPropertyNamesContextualType4_ES6.types
index bdfa569752b..9ee84176237 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType4_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType4_ES6.types
@@ -12,7 +12,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [""+"foo"]: "",    [""+"bar"]: 0} : { [x: string]: string | number; [x: number]: undefined; }
+>{    [""+"foo"]: "",    [""+"bar"]: 0} : { [x: string]: string | number; }
 
     [""+"foo"]: "",
 >""+"foo" : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType5_ES5.types b/tests/baselines/reference/computedPropertyNamesContextualType5_ES5.types
index e142fe937b9..38594f756ab 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType5_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType5_ES5.types
@@ -12,7 +12,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [+"foo"]: "",    [+"bar"]: 0} : { [x: string]: string | number; [x: number]: string | number; }
+>{    [+"foo"]: "",    [+"bar"]: 0} : { [x: number]: string | number; }
 
     [+"foo"]: "",
 >+"foo" : number
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType5_ES6.types b/tests/baselines/reference/computedPropertyNamesContextualType5_ES6.types
index 7b385b36770..a07b2e8cd95 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType5_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType5_ES6.types
@@ -12,7 +12,7 @@ interface I {
 var o: I = {
 >o : I
 >I : I
->{    [+"foo"]: "",    [+"bar"]: 0} : { [x: string]: string | number; [x: number]: string | number; }
+>{    [+"foo"]: "",    [+"bar"]: 0} : { [x: number]: string | number; }
 
     [+"foo"]: "",
 >+"foo" : number
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType6_ES5.types b/tests/baselines/reference/computedPropertyNamesContextualType6_ES5.types
index a3a393fba0c..b49724ccded 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType6_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType6_ES5.types
@@ -19,7 +19,7 @@ declare function foo<T>(obj: I<T>): T
 foo({
 >foo({    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]}) : string | (() => void) | boolean | number | number[]
 >foo : <T>(obj: I<T>) => T
->{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: string]: string | (() => void) | boolean | number | number[]; 0: () => void; p: string; }
+>{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: string]: string | (() => void) | boolean | number | number[]; [x: number]: (() => void) | number | number[]; 0: () => void; p: string; }
 
     p: "",
 >p : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType6_ES6.types b/tests/baselines/reference/computedPropertyNamesContextualType6_ES6.types
index 4abefe44843..e88959d7cdc 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType6_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType6_ES6.types
@@ -19,7 +19,7 @@ declare function foo<T>(obj: I<T>): T
 foo({
 >foo({    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]}) : string | (() => void) | boolean | number | number[]
 >foo : <T>(obj: I<T>) => T
->{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: string]: string | (() => void) | boolean | number | number[]; 0: () => void; p: string; }
+>{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: string]: string | (() => void) | boolean | number | number[]; [x: number]: (() => void) | number | number[]; 0: () => void; p: string; }
 
     p: "",
 >p : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType7_ES5.types b/tests/baselines/reference/computedPropertyNamesContextualType7_ES5.types
index ae1004c9819..083388ba975 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType7_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType7_ES5.types
@@ -19,7 +19,7 @@ declare function foo<T>(obj: I<T>): T
 foo({
 >foo({    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]}) : (() => void) | number | number[]
 >foo : <T>(obj: I<T>) => T
->{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: number]: (() => void) | number | number[]; 0: () => void; p: string; }
+>{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: string]: string | (() => void) | boolean | number | number[]; [x: number]: (() => void) | number | number[]; 0: () => void; p: string; }
 
     p: "",
 >p : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType7_ES6.types b/tests/baselines/reference/computedPropertyNamesContextualType7_ES6.types
index e98e0fb8941..bc6ae72fb4f 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType7_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesContextualType7_ES6.types
@@ -19,7 +19,7 @@ declare function foo<T>(obj: I<T>): T
 foo({
 >foo({    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]}) : (() => void) | number | number[]
 >foo : <T>(obj: I<T>) => T
->{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: number]: (() => void) | number | number[]; 0: () => void; p: string; }
+>{    p: "",    0: () => { },    ["hi" + "bye"]: true,    [0 + 1]: 0,    [+"hi"]: [0]} : { [x: string]: string | (() => void) | boolean | number | number[]; [x: number]: (() => void) | number | number[]; 0: () => void; p: string; }
 
     p: "",
 >p : string
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType8_ES5.errors.txt b/tests/baselines/reference/computedPropertyNamesContextualType8_ES5.errors.txt
index 3376243e370..ee36609095a 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType8_ES5.errors.txt
+++ b/tests/baselines/reference/computedPropertyNamesContextualType8_ES5.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts(6,5): error TS2322: Type '{ [x: string]: string | number; [x: number]: undefined; }' is not assignable to type 'I'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts(6,5): error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
   Index signatures are incompatible.
     Type 'string | number' is not assignable to type 'boolean'.
       Type 'string' is not assignable to type 'boolean'.
@@ -12,7 +12,7 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualTy
     
     var o: I = {
         ~
-!!! error TS2322: Type '{ [x: string]: string | number; [x: number]: undefined; }' is not assignable to type 'I'.
+!!! error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
 !!! error TS2322:   Index signatures are incompatible.
 !!! error TS2322:     Type 'string | number' is not assignable to type 'boolean'.
 !!! error TS2322:       Type 'string' is not assignable to type 'boolean'.
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType8_ES6.errors.txt b/tests/baselines/reference/computedPropertyNamesContextualType8_ES6.errors.txt
index e4540337ed4..1048fd2e119 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType8_ES6.errors.txt
+++ b/tests/baselines/reference/computedPropertyNamesContextualType8_ES6.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts(6,5): error TS2322: Type '{ [x: string]: string | number; [x: number]: undefined; }' is not assignable to type 'I'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts(6,5): error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
   Index signatures are incompatible.
     Type 'string | number' is not assignable to type 'boolean'.
       Type 'string' is not assignable to type 'boolean'.
@@ -12,7 +12,7 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualTy
     
     var o: I = {
         ~
-!!! error TS2322: Type '{ [x: string]: string | number; [x: number]: undefined; }' is not assignable to type 'I'.
+!!! error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
 !!! error TS2322:   Index signatures are incompatible.
 !!! error TS2322:     Type 'string | number' is not assignable to type 'boolean'.
 !!! error TS2322:       Type 'string' is not assignable to type 'boolean'.
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType9_ES5.errors.txt b/tests/baselines/reference/computedPropertyNamesContextualType9_ES5.errors.txt
index d4085a37e60..e76b3a704dc 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType9_ES5.errors.txt
+++ b/tests/baselines/reference/computedPropertyNamesContextualType9_ES5.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType9_ES5.ts(6,5): error TS2322: Type '{ [x: string]: string | number; [x: number]: string | number; }' is not assignable to type 'I'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType9_ES5.ts(6,5): error TS2322: Type '{ [x: number]: string | number; }' is not assignable to type 'I'.
   Index signatures are incompatible.
     Type 'string | number' is not assignable to type 'boolean'.
       Type 'string' is not assignable to type 'boolean'.
@@ -12,7 +12,7 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualTy
     
     var o: I = {
         ~
-!!! error TS2322: Type '{ [x: string]: string | number; [x: number]: string | number; }' is not assignable to type 'I'.
+!!! error TS2322: Type '{ [x: number]: string | number; }' is not assignable to type 'I'.
 !!! error TS2322:   Index signatures are incompatible.
 !!! error TS2322:     Type 'string | number' is not assignable to type 'boolean'.
 !!! error TS2322:       Type 'string' is not assignable to type 'boolean'.
diff --git a/tests/baselines/reference/computedPropertyNamesContextualType9_ES6.errors.txt b/tests/baselines/reference/computedPropertyNamesContextualType9_ES6.errors.txt
index eca1360c26f..468ad400c26 100644
--- a/tests/baselines/reference/computedPropertyNamesContextualType9_ES6.errors.txt
+++ b/tests/baselines/reference/computedPropertyNamesContextualType9_ES6.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType9_ES6.ts(6,5): error TS2322: Type '{ [x: string]: string | number; [x: number]: string | number; }' is not assignable to type 'I'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType9_ES6.ts(6,5): error TS2322: Type '{ [x: number]: string | number; }' is not assignable to type 'I'.
   Index signatures are incompatible.
     Type 'string | number' is not assignable to type 'boolean'.
       Type 'string' is not assignable to type 'boolean'.
@@ -12,7 +12,7 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualTy
     
     var o: I = {
         ~
-!!! error TS2322: Type '{ [x: string]: string | number; [x: number]: string | number; }' is not assignable to type 'I'.
+!!! error TS2322: Type '{ [x: number]: string | number; }' is not assignable to type 'I'.
 !!! error TS2322:   Index signatures are incompatible.
 !!! error TS2322:     Type 'string | number' is not assignable to type 'boolean'.
 !!! error TS2322:       Type 'string' is not assignable to type 'boolean'.
diff --git a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.js b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.js
index e77eb79dc70..f04ea61379d 100644
--- a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.js
+++ b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.js
@@ -26,4 +26,6 @@ var _a;
 
 
 //// [computedPropertyNamesDeclarationEmit5_ES5.d.ts]
-declare var v: {};
+declare var v: {
+    [x: string]: any;
+};
diff --git a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.types b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.types
index 62faa5c2716..0653059b535 100644
--- a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.types
+++ b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES5.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit5_ES5.ts ===
 var v = {
->v : {}
->{    ["" + ""]: 0,    ["" + ""]() { },    get ["" + ""]() { return 0; },    set ["" + ""](x) { }} : {}
+>v : { [x: string]: any; }
+>{    ["" + ""]: 0,    ["" + ""]() { },    get ["" + ""]() { return 0; },    set ["" + ""](x) { }} : { [x: string]: any; }
 
     ["" + ""]: 0,
 >"" + "" : string
diff --git a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.js b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.js
index e19ac43656e..de1f8c65d7f 100644
--- a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.js
+++ b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.js
@@ -16,4 +16,6 @@ var v = {
 
 
 //// [computedPropertyNamesDeclarationEmit5_ES6.d.ts]
-declare var v: {};
+declare var v: {
+    [x: string]: any;
+};
diff --git a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.types b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.types
index 3eb313d2687..45d1e74f24a 100644
--- a/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.types
+++ b/tests/baselines/reference/computedPropertyNamesDeclarationEmit5_ES6.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/computedProperties/computedPropertyNamesDeclarationEmit5_ES6.ts ===
 var v = {
->v : {}
->{    ["" + ""]: 0,    ["" + ""]() { },    get ["" + ""]() { return 0; },    set ["" + ""](x) { }} : {}
+>v : { [x: string]: any; }
+>{    ["" + ""]: 0,    ["" + ""]() { },    get ["" + ""]() { return 0; },    set ["" + ""](x) { }} : { [x: string]: any; }
 
     ["" + ""]: 0,
 >"" + "" : string
diff --git a/tests/baselines/reference/constEnumPropertyAccess1.types b/tests/baselines/reference/constEnumPropertyAccess1.types
index 5ed2b932bd0..f0e00fe7717 100644
--- a/tests/baselines/reference/constEnumPropertyAccess1.types
+++ b/tests/baselines/reference/constEnumPropertyAccess1.types
@@ -35,7 +35,7 @@ var o: {
 >idx : number
 
 } = {
->{        1: true    } : { [x: number]: boolean; 1: boolean; }
+>{        1: true    } : { 1: boolean; }
 
         1: true
 >true : boolean
diff --git a/tests/baselines/reference/contextualTypeAny.errors.txt b/tests/baselines/reference/contextualTypeAny.errors.txt
new file mode 100644
index 00000000000..09970be986d
--- /dev/null
+++ b/tests/baselines/reference/contextualTypeAny.errors.txt
@@ -0,0 +1,15 @@
+tests/cases/compiler/contextualTypeAny.ts(3,5): error TS2322: Type '{ p: string; q: any; }' is not assignable to type '{ [s: string]: number; }'.
+  Property 'p' is incompatible with index signature.
+    Type 'string' is not assignable to type 'number'.
+
+
+==== tests/cases/compiler/contextualTypeAny.ts (1 errors) ====
+    var x: any;
+    
+    var obj: { [s: string]: number } = { p: "", q: x };
+        ~~~
+!!! error TS2322: Type '{ p: string; q: any; }' is not assignable to type '{ [s: string]: number; }'.
+!!! error TS2322:   Property 'p' is incompatible with index signature.
+!!! error TS2322:     Type 'string' is not assignable to type 'number'.
+    
+    var arr: number[] = ["", x];
\ No newline at end of file
diff --git a/tests/baselines/reference/contextualTypeAny.symbols b/tests/baselines/reference/contextualTypeAny.symbols
deleted file mode 100644
index 5132c948a2e..00000000000
--- a/tests/baselines/reference/contextualTypeAny.symbols
+++ /dev/null
@@ -1,15 +0,0 @@
-=== tests/cases/compiler/contextualTypeAny.ts ===
-var x: any;
->x : Symbol(x, Decl(contextualTypeAny.ts, 0, 3))
-
-var obj: { [s: string]: number } = { p: "", q: x };
->obj : Symbol(obj, Decl(contextualTypeAny.ts, 2, 3))
->s : Symbol(s, Decl(contextualTypeAny.ts, 2, 12))
->p : Symbol(p, Decl(contextualTypeAny.ts, 2, 36))
->q : Symbol(q, Decl(contextualTypeAny.ts, 2, 43))
->x : Symbol(x, Decl(contextualTypeAny.ts, 0, 3))
-
-var arr: number[] = ["", x];
->arr : Symbol(arr, Decl(contextualTypeAny.ts, 4, 3))
->x : Symbol(x, Decl(contextualTypeAny.ts, 0, 3))
-
diff --git a/tests/baselines/reference/contextualTypeAny.types b/tests/baselines/reference/contextualTypeAny.types
deleted file mode 100644
index cace92d6567..00000000000
--- a/tests/baselines/reference/contextualTypeAny.types
+++ /dev/null
@@ -1,19 +0,0 @@
-=== tests/cases/compiler/contextualTypeAny.ts ===
-var x: any;
->x : any
-
-var obj: { [s: string]: number } = { p: "", q: x };
->obj : { [s: string]: number; }
->s : string
->{ p: "", q: x } : { [x: string]: any; p: string; q: any; }
->p : string
->"" : string
->q : any
->x : any
-
-var arr: number[] = ["", x];
->arr : number[]
->["", x] : any[]
->"" : string
->x : any
-
diff --git a/tests/baselines/reference/contextualTypeArrayReturnType.types b/tests/baselines/reference/contextualTypeArrayReturnType.types
index f270b33f568..6c91fd7b8b9 100644
--- a/tests/baselines/reference/contextualTypeArrayReturnType.types
+++ b/tests/baselines/reference/contextualTypeArrayReturnType.types
@@ -26,18 +26,18 @@ interface Transform3D {
 var style: IBookStyle = {
 >style : IBookStyle
 >IBookStyle : IBookStyle
->{    initialLeftPageTransforms: (width: number) => {        return [            {'ry': null }        ];    }} : { initialLeftPageTransforms: (width: number) => { [x: string]: any; 'ry': any; }[]; }
+>{    initialLeftPageTransforms: (width: number) => {        return [            {'ry': null }        ];    }} : { initialLeftPageTransforms: (width: number) => { 'ry': any; }[]; }
 
     initialLeftPageTransforms: (width: number) => {
->initialLeftPageTransforms : (width: number) => { [x: string]: any; 'ry': any; }[]
->(width: number) => {        return [            {'ry': null }        ];    } : (width: number) => { [x: string]: any; 'ry': any; }[]
+>initialLeftPageTransforms : (width: number) => { 'ry': any; }[]
+>(width: number) => {        return [            {'ry': null }        ];    } : (width: number) => { 'ry': any; }[]
 >width : number
 
         return [
->[            {'ry': null }        ] : { [x: string]: null; 'ry': null; }[]
+>[            {'ry': null }        ] : { 'ry': null; }[]
 
             {'ry': null }
->{'ry': null } : { [x: string]: null; 'ry': null; }
+>{'ry': null } : { 'ry': null; }
 >null : null
 
         ];
diff --git a/tests/baselines/reference/contextualTypeWithUnionTypeIndexSignatures.types b/tests/baselines/reference/contextualTypeWithUnionTypeIndexSignatures.types
index 2f24ad08227..965e4d21d99 100644
--- a/tests/baselines/reference/contextualTypeWithUnionTypeIndexSignatures.types
+++ b/tests/baselines/reference/contextualTypeWithUnionTypeIndexSignatures.types
@@ -69,7 +69,7 @@ var x: IWithNoStringIndexSignature | IWithStringIndexSignature1 = { z: a => a };
 >x : IWithNoStringIndexSignature | IWithStringIndexSignature1
 >IWithNoStringIndexSignature : IWithNoStringIndexSignature
 >IWithStringIndexSignature1 : IWithStringIndexSignature1
->{ z: a => a } : { [x: string]: (a: number) => number; z: (a: number) => number; }
+>{ z: a => a } : { z: (a: number) => number; }
 >z : (a: number) => number
 >a => a : (a: number) => number
 >a : number
@@ -79,7 +79,7 @@ var x: IWithNoStringIndexSignature | IWithStringIndexSignature1 = { foo: a => a
 >x : IWithNoStringIndexSignature | IWithStringIndexSignature1
 >IWithNoStringIndexSignature : IWithNoStringIndexSignature
 >IWithStringIndexSignature1 : IWithStringIndexSignature1
->{ foo: a => a } : { [x: string]: (a: any) => any; foo: (a: any) => any; }
+>{ foo: a => a } : { foo: (a: any) => any; }
 >foo : (a: any) => any
 >a => a : (a: any) => any
 >a : any
@@ -89,7 +89,7 @@ var x: IWithNoStringIndexSignature | IWithStringIndexSignature1 = { foo: "hello"
 >x : IWithNoStringIndexSignature | IWithStringIndexSignature1
 >IWithNoStringIndexSignature : IWithNoStringIndexSignature
 >IWithStringIndexSignature1 : IWithStringIndexSignature1
->{ foo: "hello" } : { [x: string]: string; foo: string; }
+>{ foo: "hello" } : { foo: string; }
 >foo : string
 >"hello" : string
 
@@ -97,7 +97,7 @@ var x2: IWithStringIndexSignature1 | IWithStringIndexSignature2 = { z: a => a.to
 >x2 : IWithStringIndexSignature1 | IWithStringIndexSignature2
 >IWithStringIndexSignature1 : IWithStringIndexSignature1
 >IWithStringIndexSignature2 : IWithStringIndexSignature2
->{ z: a => a.toString() } : { [x: string]: (a: number) => string; z: (a: number) => string; }
+>{ z: a => a.toString() } : { z: (a: number) => string; }
 >z : (a: number) => string
 >a => a.toString() : (a: number) => string
 >a : number
@@ -110,7 +110,7 @@ var x2: IWithStringIndexSignature1 | IWithStringIndexSignature2 = { z: a => a };
 >x2 : IWithStringIndexSignature1 | IWithStringIndexSignature2
 >IWithStringIndexSignature1 : IWithStringIndexSignature1
 >IWithStringIndexSignature2 : IWithStringIndexSignature2
->{ z: a => a } : { [x: string]: (a: number) => number; z: (a: number) => number; }
+>{ z: a => a } : { z: (a: number) => number; }
 >z : (a: number) => number
 >a => a : (a: number) => number
 >a : number
@@ -124,7 +124,7 @@ var x3: IWithNoNumberIndexSignature | IWithNumberIndexSignature1 = { 1: a => a }
 >x3 : IWithNoNumberIndexSignature | IWithNumberIndexSignature1
 >IWithNoNumberIndexSignature : IWithNoNumberIndexSignature
 >IWithNumberIndexSignature1 : IWithNumberIndexSignature1
->{ 1: a => a } : { [x: number]: (a: number) => number; 1: (a: number) => number; }
+>{ 1: a => a } : { 1: (a: number) => number; }
 >a => a : (a: number) => number
 >a : number
 >a : number
@@ -133,7 +133,7 @@ var x3: IWithNoNumberIndexSignature | IWithNumberIndexSignature1 = { 0: a => a }
 >x3 : IWithNoNumberIndexSignature | IWithNumberIndexSignature1
 >IWithNoNumberIndexSignature : IWithNoNumberIndexSignature
 >IWithNumberIndexSignature1 : IWithNumberIndexSignature1
->{ 0: a => a } : { [x: number]: (a: any) => any; 0: (a: any) => any; }
+>{ 0: a => a } : { 0: (a: any) => any; }
 >a => a : (a: any) => any
 >a : any
 >a : any
@@ -142,14 +142,14 @@ var x3: IWithNoNumberIndexSignature | IWithNumberIndexSignature1 = { 0: "hello"
 >x3 : IWithNoNumberIndexSignature | IWithNumberIndexSignature1
 >IWithNoNumberIndexSignature : IWithNoNumberIndexSignature
 >IWithNumberIndexSignature1 : IWithNumberIndexSignature1
->{ 0: "hello" } : { [x: number]: string; 0: string; }
+>{ 0: "hello" } : { 0: string; }
 >"hello" : string
 
 var x4: IWithNumberIndexSignature1 | IWithNumberIndexSignature2 = { 1: a => a.toString() }; // a should be number
 >x4 : IWithNumberIndexSignature1 | IWithNumberIndexSignature2
 >IWithNumberIndexSignature1 : IWithNumberIndexSignature1
 >IWithNumberIndexSignature2 : IWithNumberIndexSignature2
->{ 1: a => a.toString() } : { [x: number]: (a: number) => string; 1: (a: number) => string; }
+>{ 1: a => a.toString() } : { 1: (a: number) => string; }
 >a => a.toString() : (a: number) => string
 >a : number
 >a.toString() : string
@@ -161,7 +161,7 @@ var x4: IWithNumberIndexSignature1 | IWithNumberIndexSignature2 = { 1: a => a };
 >x4 : IWithNumberIndexSignature1 | IWithNumberIndexSignature2
 >IWithNumberIndexSignature1 : IWithNumberIndexSignature1
 >IWithNumberIndexSignature2 : IWithNumberIndexSignature2
->{ 1: a => a } : { [x: number]: (a: number) => number; 1: (a: number) => number; }
+>{ 1: a => a } : { 1: (a: number) => number; }
 >a => a : (a: number) => number
 >a : number
 >a : number
diff --git a/tests/baselines/reference/contextualTypingOfObjectLiterals.errors.txt b/tests/baselines/reference/contextualTypingOfObjectLiterals.errors.txt
deleted file mode 100644
index ac8063a4378..00000000000
--- a/tests/baselines/reference/contextualTypingOfObjectLiterals.errors.txt
+++ /dev/null
@@ -1,23 +0,0 @@
-tests/cases/compiler/contextualTypingOfObjectLiterals.ts(4,1): error TS2322: Type '{ x: string; }' is not assignable to type '{ [x: string]: string; }'.
-  Index signature is missing in type '{ x: string; }'.
-tests/cases/compiler/contextualTypingOfObjectLiterals.ts(10,3): error TS2345: Argument of type '{ x: string; }' is not assignable to parameter of type '{ [s: string]: string; }'.
-  Index signature is missing in type '{ x: string; }'.
-
-
-==== tests/cases/compiler/contextualTypingOfObjectLiterals.ts (2 errors) ====
-    var obj1: { [x: string]: string; };
-    var obj2 = {x: ""};
-    obj1 = {}; // Ok
-    obj1 = obj2; // Error - indexer doesn't match
-    ~~~~
-!!! error TS2322: Type '{ x: string; }' is not assignable to type '{ [x: string]: string; }'.
-!!! error TS2322:   Index signature is missing in type '{ x: string; }'.
-    
-    function f(x: { [s: string]: string }) { }
-    
-    f({}); // Ok
-    f(obj1); // Ok
-    f(obj2); // Error - indexer doesn't match
-      ~~~~
-!!! error TS2345: Argument of type '{ x: string; }' is not assignable to parameter of type '{ [s: string]: string; }'.
-!!! error TS2345:   Index signature is missing in type '{ x: string; }'.
\ No newline at end of file
diff --git a/tests/baselines/reference/contextualTypingOfObjectLiterals.symbols b/tests/baselines/reference/contextualTypingOfObjectLiterals.symbols
new file mode 100644
index 00000000000..afa34cfe481
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfObjectLiterals.symbols
@@ -0,0 +1,32 @@
+=== tests/cases/compiler/contextualTypingOfObjectLiterals.ts ===
+var obj1: { [x: string]: string; };
+>obj1 : Symbol(obj1, Decl(contextualTypingOfObjectLiterals.ts, 0, 3))
+>x : Symbol(x, Decl(contextualTypingOfObjectLiterals.ts, 0, 13))
+
+var obj2 = {x: ""};
+>obj2 : Symbol(obj2, Decl(contextualTypingOfObjectLiterals.ts, 1, 3))
+>x : Symbol(x, Decl(contextualTypingOfObjectLiterals.ts, 1, 12))
+
+obj1 = {}; // Ok
+>obj1 : Symbol(obj1, Decl(contextualTypingOfObjectLiterals.ts, 0, 3))
+
+obj1 = obj2; // Error - indexer doesn't match
+>obj1 : Symbol(obj1, Decl(contextualTypingOfObjectLiterals.ts, 0, 3))
+>obj2 : Symbol(obj2, Decl(contextualTypingOfObjectLiterals.ts, 1, 3))
+
+function f(x: { [s: string]: string }) { }
+>f : Symbol(f, Decl(contextualTypingOfObjectLiterals.ts, 3, 12))
+>x : Symbol(x, Decl(contextualTypingOfObjectLiterals.ts, 5, 11))
+>s : Symbol(s, Decl(contextualTypingOfObjectLiterals.ts, 5, 17))
+
+f({}); // Ok
+>f : Symbol(f, Decl(contextualTypingOfObjectLiterals.ts, 3, 12))
+
+f(obj1); // Ok
+>f : Symbol(f, Decl(contextualTypingOfObjectLiterals.ts, 3, 12))
+>obj1 : Symbol(obj1, Decl(contextualTypingOfObjectLiterals.ts, 0, 3))
+
+f(obj2); // Error - indexer doesn't match
+>f : Symbol(f, Decl(contextualTypingOfObjectLiterals.ts, 3, 12))
+>obj2 : Symbol(obj2, Decl(contextualTypingOfObjectLiterals.ts, 1, 3))
+
diff --git a/tests/baselines/reference/contextualTypingOfObjectLiterals.types b/tests/baselines/reference/contextualTypingOfObjectLiterals.types
new file mode 100644
index 00000000000..a99fb2f39af
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfObjectLiterals.types
@@ -0,0 +1,41 @@
+=== tests/cases/compiler/contextualTypingOfObjectLiterals.ts ===
+var obj1: { [x: string]: string; };
+>obj1 : { [x: string]: string; }
+>x : string
+
+var obj2 = {x: ""};
+>obj2 : { x: string; }
+>{x: ""} : { x: string; }
+>x : string
+>"" : string
+
+obj1 = {}; // Ok
+>obj1 = {} : {}
+>obj1 : { [x: string]: string; }
+>{} : {}
+
+obj1 = obj2; // Error - indexer doesn't match
+>obj1 = obj2 : { x: string; }
+>obj1 : { [x: string]: string; }
+>obj2 : { x: string; }
+
+function f(x: { [s: string]: string }) { }
+>f : (x: { [s: string]: string; }) => void
+>x : { [s: string]: string; }
+>s : string
+
+f({}); // Ok
+>f({}) : void
+>f : (x: { [s: string]: string; }) => void
+>{} : {}
+
+f(obj1); // Ok
+>f(obj1) : void
+>f : (x: { [s: string]: string; }) => void
+>obj1 : { [x: string]: string; }
+
+f(obj2); // Error - indexer doesn't match
+>f(obj2) : void
+>f : (x: { [s: string]: string; }) => void
+>obj2 : { x: string; }
+
diff --git a/tests/baselines/reference/declarationEmitIdentifierPredicates01.js b/tests/baselines/reference/declarationEmitIdentifierPredicates01.js
new file mode 100644
index 00000000000..73141eb9af9
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitIdentifierPredicates01.js
@@ -0,0 +1,16 @@
+//// [declarationEmitIdentifierPredicates01.ts]
+
+export function f(x: any): x is number {
+    return typeof x === "number";
+}
+
+//// [declarationEmitIdentifierPredicates01.js]
+"use strict";
+function f(x) {
+    return typeof x === "number";
+}
+exports.f = f;
+
+
+//// [declarationEmitIdentifierPredicates01.d.ts]
+export declare function f(x: any): x is number;
diff --git a/tests/baselines/reference/declarationEmitIdentifierPredicates01.symbols b/tests/baselines/reference/declarationEmitIdentifierPredicates01.symbols
new file mode 100644
index 00000000000..eb8b1151ceb
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitIdentifierPredicates01.symbols
@@ -0,0 +1,10 @@
+=== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicates01.ts ===
+
+export function f(x: any): x is number {
+>f : Symbol(f, Decl(declarationEmitIdentifierPredicates01.ts, 0, 0))
+>x : Symbol(x, Decl(declarationEmitIdentifierPredicates01.ts, 1, 18))
+>x : Symbol(x, Decl(declarationEmitIdentifierPredicates01.ts, 1, 18))
+
+    return typeof x === "number";
+>x : Symbol(x, Decl(declarationEmitIdentifierPredicates01.ts, 1, 18))
+}
diff --git a/tests/baselines/reference/declarationEmitIdentifierPredicates01.types b/tests/baselines/reference/declarationEmitIdentifierPredicates01.types
new file mode 100644
index 00000000000..7d8a5668265
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitIdentifierPredicates01.types
@@ -0,0 +1,13 @@
+=== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicates01.ts ===
+
+export function f(x: any): x is number {
+>f : (x: any) => x is number
+>x : any
+>x : any
+
+    return typeof x === "number";
+>typeof x === "number" : boolean
+>typeof x : string
+>x : any
+>"number" : string
+}
diff --git a/tests/baselines/reference/declarationEmitIdentifierPredicatesWithPrivateName01.errors.txt b/tests/baselines/reference/declarationEmitIdentifierPredicatesWithPrivateName01.errors.txt
new file mode 100644
index 00000000000..e9084c45490
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitIdentifierPredicatesWithPrivateName01.errors.txt
@@ -0,0 +1,14 @@
+tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicatesWithPrivateName01.ts(6,33): error TS4060: Return type of exported function has or is using private name 'I'.
+
+
+==== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicatesWithPrivateName01.ts (1 errors) ====
+    
+    interface I {
+        a: number;
+    }
+    
+    export function f(x: any): x is I {
+                                    ~
+!!! error TS4060: Return type of exported function has or is using private name 'I'.
+        return typeof x.a === "number";
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitIdentifierPredicatesWithPrivateName01.js b/tests/baselines/reference/declarationEmitIdentifierPredicatesWithPrivateName01.js
new file mode 100644
index 00000000000..234542d8d99
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitIdentifierPredicatesWithPrivateName01.js
@@ -0,0 +1,16 @@
+//// [declarationEmitIdentifierPredicatesWithPrivateName01.ts]
+
+interface I {
+    a: number;
+}
+
+export function f(x: any): x is I {
+    return typeof x.a === "number";
+}
+
+//// [declarationEmitIdentifierPredicatesWithPrivateName01.js]
+"use strict";
+function f(x) {
+    return typeof x.a === "number";
+}
+exports.f = f;
diff --git a/tests/baselines/reference/declarationEmitThisPredicates01.js b/tests/baselines/reference/declarationEmitThisPredicates01.js
new file mode 100644
index 00000000000..d05b5c46dad
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicates01.js
@@ -0,0 +1,43 @@
+//// [declarationEmitThisPredicates01.ts]
+
+export class C {
+    m(): this is D {
+        return this instanceof D;
+    }
+}
+
+export class D extends C {
+}
+
+//// [declarationEmitThisPredicates01.js]
+"use strict";
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var C = (function () {
+    function C() {
+    }
+    C.prototype.m = function () {
+        return this instanceof D;
+    };
+    return C;
+}());
+exports.C = C;
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        _super.apply(this, arguments);
+    }
+    return D;
+}(C));
+exports.D = D;
+
+
+//// [declarationEmitThisPredicates01.d.ts]
+export declare class C {
+    m(): this is D;
+}
+export declare class D extends C {
+}
diff --git a/tests/baselines/reference/declarationEmitThisPredicates01.symbols b/tests/baselines/reference/declarationEmitThisPredicates01.symbols
new file mode 100644
index 00000000000..d57f937d6c5
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicates01.symbols
@@ -0,0 +1,19 @@
+=== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates01.ts ===
+
+export class C {
+>C : Symbol(C, Decl(declarationEmitThisPredicates01.ts, 0, 0))
+
+    m(): this is D {
+>m : Symbol(m, Decl(declarationEmitThisPredicates01.ts, 1, 16))
+>D : Symbol(D, Decl(declarationEmitThisPredicates01.ts, 5, 1))
+
+        return this instanceof D;
+>this : Symbol(C, Decl(declarationEmitThisPredicates01.ts, 0, 0))
+>D : Symbol(D, Decl(declarationEmitThisPredicates01.ts, 5, 1))
+    }
+}
+
+export class D extends C {
+>D : Symbol(D, Decl(declarationEmitThisPredicates01.ts, 5, 1))
+>C : Symbol(C, Decl(declarationEmitThisPredicates01.ts, 0, 0))
+}
diff --git a/tests/baselines/reference/declarationEmitThisPredicates01.types b/tests/baselines/reference/declarationEmitThisPredicates01.types
new file mode 100644
index 00000000000..9d801a40965
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicates01.types
@@ -0,0 +1,20 @@
+=== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates01.ts ===
+
+export class C {
+>C : C
+
+    m(): this is D {
+>m : () => this is D
+>D : D
+
+        return this instanceof D;
+>this instanceof D : boolean
+>this : this
+>D : typeof D
+    }
+}
+
+export class D extends C {
+>D : D
+>C : C
+}
diff --git a/tests/baselines/reference/declarationEmitThisPredicates02.errors.txt b/tests/baselines/reference/declarationEmitThisPredicates02.errors.txt
new file mode 100644
index 00000000000..4d95cf01136
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicates02.errors.txt
@@ -0,0 +1,19 @@
+tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates02.ts(9,10): error TS2526: A 'this' type is available only in a non-static member of a class or interface.
+
+
+==== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates02.ts (1 errors) ====
+    
+    export interface Foo {
+        a: string;
+        b: number;
+        c: boolean;
+    }
+    
+    export const obj = {
+        m(): this is Foo {
+             ~~~~
+!!! error TS2526: A 'this' type is available only in a non-static member of a class or interface.
+            let dis = this as Foo;
+            return dis.a != null && dis.b != null && dis.c != null;
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitThisPredicates02.js b/tests/baselines/reference/declarationEmitThisPredicates02.js
new file mode 100644
index 00000000000..e938a615b6d
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicates02.js
@@ -0,0 +1,34 @@
+//// [declarationEmitThisPredicates02.ts]
+
+export interface Foo {
+    a: string;
+    b: number;
+    c: boolean;
+}
+
+export const obj = {
+    m(): this is Foo {
+        let dis = this as Foo;
+        return dis.a != null && dis.b != null && dis.c != null;
+    }
+}
+
+//// [declarationEmitThisPredicates02.js]
+"use strict";
+exports.obj = {
+    m: function () {
+        var dis = this;
+        return dis.a != null && dis.b != null && dis.c != null;
+    }
+};
+
+
+//// [declarationEmitThisPredicates02.d.ts]
+export interface Foo {
+    a: string;
+    b: number;
+    c: boolean;
+}
+export declare const obj: {
+    m(): this is Foo;
+};
diff --git a/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName01.errors.txt b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName01.errors.txt
new file mode 100644
index 00000000000..67c76283f80
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName01.errors.txt
@@ -0,0 +1,15 @@
+tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName01.ts(3,18): error TS4055: Return type of public method from exported class has or is using private name 'D'.
+
+
+==== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName01.ts (1 errors) ====
+    
+    export class C {
+        m(): this is D {
+                     ~
+!!! error TS4055: Return type of public method from exported class has or is using private name 'D'.
+            return this instanceof D;
+        }
+    }
+    
+    class D extends C {
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName01.js b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName01.js
new file mode 100644
index 00000000000..e34dcc9810f
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName01.js
@@ -0,0 +1,34 @@
+//// [declarationEmitThisPredicatesWithPrivateName01.ts]
+
+export class C {
+    m(): this is D {
+        return this instanceof D;
+    }
+}
+
+class D extends C {
+}
+
+//// [declarationEmitThisPredicatesWithPrivateName01.js]
+"use strict";
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var C = (function () {
+    function C() {
+    }
+    C.prototype.m = function () {
+        return this instanceof D;
+    };
+    return C;
+}());
+exports.C = C;
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        _super.apply(this, arguments);
+    }
+    return D;
+}(C));
diff --git a/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.errors.txt b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.errors.txt
new file mode 100644
index 00000000000..86c0f478133
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.errors.txt
@@ -0,0 +1,22 @@
+tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName02.ts(8,14): error TS4025: Exported variable 'obj' has or is using private name 'Foo'.
+tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName02.ts(9,10): error TS2526: A 'this' type is available only in a non-static member of a class or interface.
+
+
+==== tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName02.ts (2 errors) ====
+    
+    interface Foo {
+        a: string;
+        b: number;
+        c: boolean;
+    }
+    
+    export const obj = {
+                 ~~~
+!!! error TS4025: Exported variable 'obj' has or is using private name 'Foo'.
+        m(): this is Foo {
+             ~~~~
+!!! error TS2526: A 'this' type is available only in a non-static member of a class or interface.
+            let dis = this as Foo;
+            return dis.a != null && dis.b != null && dis.c != null;
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.js b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.js
new file mode 100644
index 00000000000..df0d5b7903a
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.js
@@ -0,0 +1,23 @@
+//// [declarationEmitThisPredicatesWithPrivateName02.ts]
+
+interface Foo {
+    a: string;
+    b: number;
+    c: boolean;
+}
+
+export const obj = {
+    m(): this is Foo {
+        let dis = this as Foo;
+        return dis.a != null && dis.b != null && dis.c != null;
+    }
+}
+
+//// [declarationEmitThisPredicatesWithPrivateName02.js]
+"use strict";
+exports.obj = {
+    m: function () {
+        var dis = this;
+        return dis.a != null && dis.b != null && dis.c != null;
+    }
+};
diff --git a/tests/baselines/reference/declarationsAndAssignments.errors.txt b/tests/baselines/reference/declarationsAndAssignments.errors.txt
index 7c4671022ea..517eaafe4ab 100644
--- a/tests/baselines/reference/declarationsAndAssignments.errors.txt
+++ b/tests/baselines/reference/declarationsAndAssignments.errors.txt
@@ -11,8 +11,8 @@ tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(62,13):
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(62,16): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(63,13): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(63,16): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
-tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(67,9): error TS2461: Type '{ [x: number]: undefined; }' is not an array type.
-tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(68,9): error TS2461: Type '{ [x: number]: number; 0: number; 1: number; }' is not an array type.
+tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(67,9): error TS2461: Type '{}' is not an array type.
+tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(68,9): error TS2461: Type '{ 0: number; 1: number; }' is not an array type.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(73,11): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(73,14): error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
 tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(74,11): error TS2459: Type 'undefined[]' has no property 'a' and no string index signature.
@@ -122,10 +122,10 @@ tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(138,9):
     function f9() {
         var [a, b] = {};                // Error, not array type
             ~~~~~~
-!!! error TS2461: Type '{ [x: number]: undefined; }' is not an array type.
+!!! error TS2461: Type '{}' is not an array type.
         var [c, d] = { 0: 10, 1: 20 };  // Error, not array type
             ~~~~~~
-!!! error TS2461: Type '{ [x: number]: number; 0: number; 1: number; }' is not an array type.
+!!! error TS2461: Type '{ 0: number; 1: number; }' is not an array type.
         var [e, f] = [10, 20];
     }
     
diff --git a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES5.types b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES5.types
index 476b5bee0cc..cb6052d93fd 100644
--- a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES5.types
+++ b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES5.types
@@ -69,7 +69,7 @@ function foo(): F {
 >F : F
 
     return {
->{        1: true    } : { [x: number]: boolean; 1: boolean; }
+>{        1: true    } : { 1: boolean; }
 
         1: true
 >true : boolean
@@ -82,7 +82,7 @@ function bar(): F {
 >F : F
 
     return {
->{        2: true    } : { [x: number]: boolean; 2: boolean; }
+>{        2: true    } : { 2: boolean; }
 
         2: true
 >true : boolean
@@ -114,7 +114,7 @@ function foo1(): F1 {
 >F1 : F1
 
     return {
->{        "prop1": 2    } : { [x: string]: number; "prop1": number; }
+>{        "prop1": 2    } : { "prop1": number; }
 
         "prop1": 2
 >2 : number
diff --git a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES6.types b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES6.types
index 7a7f631eddf..2d77c20f65b 100644
--- a/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES6.types
+++ b/tests/baselines/reference/destructuringObjectBindingPatternAndAssignment1ES6.types
@@ -69,7 +69,7 @@ function foo(): F {
 >F : F
 
     return {
->{        1: true    } : { [x: number]: boolean; 1: boolean; }
+>{        1: true    } : { 1: boolean; }
 
         1: true
 >true : boolean
@@ -82,7 +82,7 @@ function bar(): F {
 >F : F
 
     return {
->{        2: true    } : { [x: number]: boolean; 2: boolean; }
+>{        2: true    } : { 2: boolean; }
 
         2: true
 >true : boolean
@@ -114,7 +114,7 @@ function foo1(): F1 {
 >F1 : F1
 
     return {
->{        "prop1": 2    } : { [x: string]: number; "prop1": number; }
+>{        "prop1": 2    } : { "prop1": number; }
 
         "prop1": 2
 >2 : number
diff --git a/tests/baselines/reference/exportRedeclarationTypeAliases.js b/tests/baselines/reference/exportRedeclarationTypeAliases.js
new file mode 100644
index 00000000000..b1e2e200634
--- /dev/null
+++ b/tests/baselines/reference/exportRedeclarationTypeAliases.js
@@ -0,0 +1,9 @@
+//// [exportRedeclarationTypeAliases.ts]
+export type Foo = number;
+export function Foo(): number;
+export function Foo(): any {}
+
+//// [exportRedeclarationTypeAliases.js]
+"use strict";
+function Foo() { }
+exports.Foo = Foo;
diff --git a/tests/baselines/reference/exportRedeclarationTypeAliases.symbols b/tests/baselines/reference/exportRedeclarationTypeAliases.symbols
new file mode 100644
index 00000000000..6561692e307
--- /dev/null
+++ b/tests/baselines/reference/exportRedeclarationTypeAliases.symbols
@@ -0,0 +1,10 @@
+=== tests/cases/compiler/exportRedeclarationTypeAliases.ts ===
+export type Foo = number;
+>Foo : Symbol(Foo, Decl(exportRedeclarationTypeAliases.ts, 0, 0), Decl(exportRedeclarationTypeAliases.ts, 0, 25), Decl(exportRedeclarationTypeAliases.ts, 1, 30))
+
+export function Foo(): number;
+>Foo : Symbol(Foo, Decl(exportRedeclarationTypeAliases.ts, 0, 0), Decl(exportRedeclarationTypeAliases.ts, 0, 25), Decl(exportRedeclarationTypeAliases.ts, 1, 30))
+
+export function Foo(): any {}
+>Foo : Symbol(Foo, Decl(exportRedeclarationTypeAliases.ts, 0, 0), Decl(exportRedeclarationTypeAliases.ts, 0, 25), Decl(exportRedeclarationTypeAliases.ts, 1, 30))
+
diff --git a/tests/baselines/reference/exportRedeclarationTypeAliases.types b/tests/baselines/reference/exportRedeclarationTypeAliases.types
new file mode 100644
index 00000000000..f5c987373b6
--- /dev/null
+++ b/tests/baselines/reference/exportRedeclarationTypeAliases.types
@@ -0,0 +1,10 @@
+=== tests/cases/compiler/exportRedeclarationTypeAliases.ts ===
+export type Foo = number;
+>Foo : number
+
+export function Foo(): number;
+>Foo : () => number
+
+export function Foo(): any {}
+>Foo : () => number
+
diff --git a/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types b/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types
index e1bfd195698..9825a75a220 100644
--- a/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types
+++ b/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types
@@ -26,7 +26,7 @@ var moduleMap: { [key: string]: IHasVisualizationModel } = {
 >moduleMap : { [key: string]: IHasVisualizationModel; }
 >key : string
 >IHasVisualizationModel : IHasVisualizationModel
->{    "moduleA": moduleA,    "moduleB": moduleB} : { [x: string]: typeof moduleA; "moduleA": typeof moduleA; "moduleB": typeof moduleB; }
+>{    "moduleA": moduleA,    "moduleB": moduleB} : { "moduleA": typeof moduleA; "moduleB": typeof moduleB; }
 
     "moduleA": moduleA,
 >moduleA : typeof moduleA
diff --git a/tests/baselines/reference/generatorTypeCheck39.errors.txt b/tests/baselines/reference/generatorTypeCheck39.errors.txt
index ae24837f712..aabb5a47a35 100644
--- a/tests/baselines/reference/generatorTypeCheck39.errors.txt
+++ b/tests/baselines/reference/generatorTypeCheck39.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck39.ts(5,16): error TS1163: A 'yield' expression is only allowed in a generator body.
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck39.ts(6,11): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.
+tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck39.ts(6,11): 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/conformance/es6/yieldExpressions/generatorTypeCheck39.ts(7,13): error TS1163: A 'yield' expression is only allowed in a generator body.
 
 
@@ -13,7 +13,7 @@ tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck39.ts(7,13): erro
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
         class C {
               ~
-!!! error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.
+!!! 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.
             x = yield 0;
                 ~~~~~
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
diff --git a/tests/baselines/reference/generatorTypeCheck41.types b/tests/baselines/reference/generatorTypeCheck41.types
index 926aef95ce5..0bed082dc43 100644
--- a/tests/baselines/reference/generatorTypeCheck41.types
+++ b/tests/baselines/reference/generatorTypeCheck41.types
@@ -3,8 +3,8 @@ function* g() {
 >g : () => IterableIterator<number>
 
     let x = {
->x : {}
->{        [yield 0]: 0    } : {}
+>x : { [x: number]: number; }
+>{        [yield 0]: 0    } : { [x: number]: number; }
 
         [yield 0]: 0
 >yield 0 : any
diff --git a/tests/baselines/reference/generatorTypeCheck42.types b/tests/baselines/reference/generatorTypeCheck42.types
index 855c4697f40..7538b8f2499 100644
--- a/tests/baselines/reference/generatorTypeCheck42.types
+++ b/tests/baselines/reference/generatorTypeCheck42.types
@@ -3,8 +3,8 @@ function* g() {
 >g : () => IterableIterator<number>
 
     let x = {
->x : {}
->{        [yield 0]() {        }    } : {}
+>x : { [x: number]: () => void; }
+>{        [yield 0]() {        }    } : { [x: number]: () => void; }
 
         [yield 0]() {
 >yield 0 : any
diff --git a/tests/baselines/reference/generatorTypeCheck43.types b/tests/baselines/reference/generatorTypeCheck43.types
index 50fc7e30c86..a132dfcb015 100644
--- a/tests/baselines/reference/generatorTypeCheck43.types
+++ b/tests/baselines/reference/generatorTypeCheck43.types
@@ -3,8 +3,8 @@ function* g() {
 >g : () => IterableIterator<number>
 
     let x = {
->x : {}
->{        *[yield 0]() {        }    } : {}
+>x : { [x: number]: () => IterableIterator<any>; }
+>{        *[yield 0]() {        }    } : { [x: number]: () => IterableIterator<any>; }
 
         *[yield 0]() {
 >yield 0 : any
diff --git a/tests/baselines/reference/generatorTypeCheck44.types b/tests/baselines/reference/generatorTypeCheck44.types
index 2fc67f90556..5c432e41cbe 100644
--- a/tests/baselines/reference/generatorTypeCheck44.types
+++ b/tests/baselines/reference/generatorTypeCheck44.types
@@ -3,8 +3,8 @@ function* g() {
 >g : () => IterableIterator<number>
 
     let x = {
->x : {}
->{        get [yield 0]() {            return 0;        }    } : {}
+>x : { [x: number]: number; }
+>{        get [yield 0]() {            return 0;        }    } : { [x: number]: number; }
 
         get [yield 0]() {
 >yield 0 : any
diff --git a/tests/baselines/reference/generatorTypeCheck59.errors.txt b/tests/baselines/reference/generatorTypeCheck59.errors.txt
index d8179803821..cba90154701 100644
--- a/tests/baselines/reference/generatorTypeCheck59.errors.txt
+++ b/tests/baselines/reference/generatorTypeCheck59.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck59.ts(3,11): error TS1163: A 'yield' expression is only allowed in a generator body.
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck59.ts(4,9): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.
+tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck59.ts(4,9): 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/conformance/es6/yieldExpressions/generatorTypeCheck59.ts (2 errors) ====
@@ -10,6 +10,6 @@ tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck59.ts(4,9): error
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
             m() { }
             ~
-!!! error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.
+!!! 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.
         };
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/generatorTypeCheck61.errors.txt b/tests/baselines/reference/generatorTypeCheck61.errors.txt
index b38e96d31ce..ccc99f7ffbd 100644
--- a/tests/baselines/reference/generatorTypeCheck61.errors.txt
+++ b/tests/baselines/reference/generatorTypeCheck61.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck61.ts(2,7): error TS1163: A 'yield' expression is only allowed in a generator body.
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck61.ts(3,11): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.
+tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck61.ts(3,11): 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/conformance/es6/yieldExpressions/generatorTypeCheck61.ts (2 errors) ====
@@ -9,5 +9,5 @@ tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck61.ts(3,11): erro
 !!! error TS1163: A 'yield' expression is only allowed in a generator body.
         class C {};
               ~
-!!! error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Specify '--experimentalDecorators' to remove this warning.
+!!! 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.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/genericBaseClassLiteralProperty2.types b/tests/baselines/reference/genericBaseClassLiteralProperty2.types
index d7d512165f0..3e320824925 100644
--- a/tests/baselines/reference/genericBaseClassLiteralProperty2.types
+++ b/tests/baselines/reference/genericBaseClassLiteralProperty2.types
@@ -14,11 +14,11 @@ class BaseCollection2<TItem extends CollectionItem2> {
 
     constructor() {
         this._itemsByKey = {};
->this._itemsByKey = {} : { [x: string]: undefined; }
+>this._itemsByKey = {} : {}
 >this._itemsByKey : { [key: string]: TItem; }
 >this : this
 >_itemsByKey : { [key: string]: TItem; }
->{} : { [x: string]: undefined; }
+>{} : {}
     }
 }
 
diff --git a/tests/baselines/reference/genericCallWithTupleType.errors.txt b/tests/baselines/reference/genericCallWithTupleType.errors.txt
index d03f8d5e68a..bcf580320e5 100644
--- a/tests/baselines/reference/genericCallWithTupleType.errors.txt
+++ b/tests/baselines/reference/genericCallWithTupleType.errors.txt
@@ -9,9 +9,9 @@ tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTup
 tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTupleType.ts(22,1): error TS2322: Type '[number, string]' is not assignable to type '[string, number]'.
   Types of property '0' are incompatible.
     Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTupleType.ts(23,1): error TS2322: Type '[{ [x: number]: undefined; }, {}]' is not assignable to type '[string, number]'.
+tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTupleType.ts(23,1): error TS2322: Type '[{}, {}]' is not assignable to type '[string, number]'.
   Types of property '0' are incompatible.
-    Type '{ [x: number]: undefined; }' is not assignable to type 'string'.
+    Type '{}' is not assignable to type 'string'.
 tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTupleType.ts(24,1): error TS2322: Type '[{}]' is not assignable to type '[{}, {}]'.
   Property '1' is missing in type '[{}]'.
 
@@ -55,9 +55,9 @@ tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTup
 !!! error TS2322:     Type 'number' is not assignable to type 'string'.
     i1.tuple1 = [{}, {}];
     ~~~~~~~~~
-!!! error TS2322: Type '[{ [x: number]: undefined; }, {}]' is not assignable to type '[string, number]'.
+!!! error TS2322: Type '[{}, {}]' is not assignable to type '[string, number]'.
 !!! error TS2322:   Types of property '0' are incompatible.
-!!! error TS2322:     Type '{ [x: number]: undefined; }' is not assignable to type 'string'.
+!!! error TS2322:     Type '{}' is not assignable to type 'string'.
     i2.tuple1 = [{}];
     ~~~~~~~~~
 !!! error TS2322: Type '[{}]' is not assignable to type '[{}, {}]'.
diff --git a/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types b/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types
index 337993dc2a6..a316773e5c8 100644
--- a/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types
+++ b/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types
@@ -8,7 +8,7 @@ class LazyArray<T> {
 ><{ [objectId: string]: T; }>{} : { [objectId: string]: T; }
 >objectId : string
 >T : T
->{} : { [x: string]: undefined; }
+>{} : {}
 
     array() {
 >array : () => { [objectId: string]: T; }
diff --git a/tests/baselines/reference/implicitAnyInAmbientDeclaration.errors.txt b/tests/baselines/reference/implicitAnyInAmbientDeclaration.errors.txt
index 1e66f26d0d2..493fc13db04 100644
--- a/tests/baselines/reference/implicitAnyInAmbientDeclaration.errors.txt
+++ b/tests/baselines/reference/implicitAnyInAmbientDeclaration.errors.txt
@@ -1,10 +1,9 @@
 tests/cases/compiler/implicitAnyInAmbientDeclaration.ts(3,9): error TS7008: Member 'publicMember' implicitly has an 'any' type.
 tests/cases/compiler/implicitAnyInAmbientDeclaration.ts(6,16): error TS7010: 'publicFunction', which lacks return-type annotation, implicitly has an 'any' return type.
 tests/cases/compiler/implicitAnyInAmbientDeclaration.ts(6,31): error TS7006: Parameter 'x' implicitly has an 'any' type.
-tests/cases/compiler/implicitAnyInAmbientDeclaration.ts(8,9): error TS1089: 'private' modifier cannot appear on a constructor declaration.
 
 
-==== tests/cases/compiler/implicitAnyInAmbientDeclaration.ts (4 errors) ====
+==== tests/cases/compiler/implicitAnyInAmbientDeclaration.ts (3 errors) ====
     module Test {
         declare class C {
             public publicMember;  // this should be an error
@@ -19,7 +18,5 @@ tests/cases/compiler/implicitAnyInAmbientDeclaration.ts(8,9): error TS1089: 'pri
 !!! error TS7006: Parameter 'x' implicitly has an 'any' type.
             private privateFunction(privateParam);  // this should not be an error
             private constructor(privateParam);
-            ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/implicitAnyInAmbientDeclaration2.d.errors.txt b/tests/baselines/reference/implicitAnyInAmbientDeclaration2.d.errors.txt
index 54fe39e2efe..03de82c731d 100644
--- a/tests/baselines/reference/implicitAnyInAmbientDeclaration2.d.errors.txt
+++ b/tests/baselines/reference/implicitAnyInAmbientDeclaration2.d.errors.txt
@@ -4,11 +4,10 @@ tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts(2,13): error TS7005:
 tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts(4,5): error TS7008: Member 'publicMember' implicitly has an 'any' type.
 tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts(7,12): error TS7010: 'publicFunction', which lacks return-type annotation, implicitly has an 'any' return type.
 tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts(7,27): error TS7006: Parameter 'x' implicitly has an 'any' type.
-tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts(9,5): error TS1089: 'private' modifier cannot appear on a constructor declaration.
 tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts(13,24): error TS7006: Parameter 'publicConsParam' implicitly has an 'any' type.
 
 
-==== tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts (8 errors) ====
+==== tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts (7 errors) ====
     declare function foo(x);  // this should be an error
                      ~~~
 !!! error TS7010: 'foo', which lacks return-type annotation, implicitly has an 'any' return type.
@@ -30,8 +29,6 @@ tests/cases/compiler/implicitAnyInAmbientDeclaration2.d.ts(13,24): error TS7006:
 !!! error TS7006: Parameter 'x' implicitly has an 'any' type.
         private privateFunction(privateParam);  // this should not be an error
         private constructor(privateParam);  // this should not be an error
-        ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
     }
     
     declare class D {
diff --git a/tests/baselines/reference/implicitIndexSignatures.js b/tests/baselines/reference/implicitIndexSignatures.js
new file mode 100644
index 00000000000..6403f1f1543
--- /dev/null
+++ b/tests/baselines/reference/implicitIndexSignatures.js
@@ -0,0 +1,85 @@
+//// [implicitIndexSignatures.ts]
+type StringMap = { [x: string]: string };
+
+const empty1 = {};
+let empty2: {};
+const names1 = { a: "foo", b: "bar" };
+let names2: { a: string, b: string };
+let map: StringMap;
+map = { x: "xxx", y: "yyy" };
+map = empty1;
+map = empty2;
+map = names1;
+map = names2;
+
+declare function getStringIndexValue<T>(map: { [x: string]: T }): T;
+declare function getNumberIndexValue<T>(map: { [x: number]: T }): T;
+
+function f1() {
+    const o1 = { a: 1, b: 2 };
+    let o2: { a: number, b: number };
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+}
+
+function f2() {
+    const o1 = { a: "1", b: "2" };
+    let o2: { a: string, b: string };
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+}
+
+function f3() {
+    const o1 = { a: 1, b: "2" };
+    let o2: { a: number, b: string };
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+}
+
+function f4() {
+    const o1 = { 0: "0", 1: "1", count: 2 };
+    let o2: { 0: string, 1: string, count: number };    
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+    const v3 = getNumberIndexValue(o1);
+    const v4 = getNumberIndexValue(o2);
+}
+
+
+//// [implicitIndexSignatures.js]
+var empty1 = {};
+var empty2;
+var names1 = { a: "foo", b: "bar" };
+var names2;
+var map;
+map = { x: "xxx", y: "yyy" };
+map = empty1;
+map = empty2;
+map = names1;
+map = names2;
+function f1() {
+    var o1 = { a: 1, b: 2 };
+    var o2;
+    var v1 = getStringIndexValue(o1);
+    var v2 = getStringIndexValue(o2);
+}
+function f2() {
+    var o1 = { a: "1", b: "2" };
+    var o2;
+    var v1 = getStringIndexValue(o1);
+    var v2 = getStringIndexValue(o2);
+}
+function f3() {
+    var o1 = { a: 1, b: "2" };
+    var o2;
+    var v1 = getStringIndexValue(o1);
+    var v2 = getStringIndexValue(o2);
+}
+function f4() {
+    var o1 = { 0: "0", 1: "1", count: 2 };
+    var o2;
+    var v1 = getStringIndexValue(o1);
+    var v2 = getStringIndexValue(o2);
+    var v3 = getNumberIndexValue(o1);
+    var v4 = getNumberIndexValue(o2);
+}
diff --git a/tests/baselines/reference/implicitIndexSignatures.symbols b/tests/baselines/reference/implicitIndexSignatures.symbols
new file mode 100644
index 00000000000..a014e7e942c
--- /dev/null
+++ b/tests/baselines/reference/implicitIndexSignatures.symbols
@@ -0,0 +1,166 @@
+=== tests/cases/compiler/implicitIndexSignatures.ts ===
+type StringMap = { [x: string]: string };
+>StringMap : Symbol(StringMap, Decl(implicitIndexSignatures.ts, 0, 0))
+>x : Symbol(x, Decl(implicitIndexSignatures.ts, 0, 20))
+
+const empty1 = {};
+>empty1 : Symbol(empty1, Decl(implicitIndexSignatures.ts, 2, 5))
+
+let empty2: {};
+>empty2 : Symbol(empty2, Decl(implicitIndexSignatures.ts, 3, 3))
+
+const names1 = { a: "foo", b: "bar" };
+>names1 : Symbol(names1, Decl(implicitIndexSignatures.ts, 4, 5))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 4, 16))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 4, 26))
+
+let names2: { a: string, b: string };
+>names2 : Symbol(names2, Decl(implicitIndexSignatures.ts, 5, 3))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 5, 13))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 5, 24))
+
+let map: StringMap;
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 6, 3))
+>StringMap : Symbol(StringMap, Decl(implicitIndexSignatures.ts, 0, 0))
+
+map = { x: "xxx", y: "yyy" };
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 6, 3))
+>x : Symbol(x, Decl(implicitIndexSignatures.ts, 7, 7))
+>y : Symbol(y, Decl(implicitIndexSignatures.ts, 7, 17))
+
+map = empty1;
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 6, 3))
+>empty1 : Symbol(empty1, Decl(implicitIndexSignatures.ts, 2, 5))
+
+map = empty2;
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 6, 3))
+>empty2 : Symbol(empty2, Decl(implicitIndexSignatures.ts, 3, 3))
+
+map = names1;
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 6, 3))
+>names1 : Symbol(names1, Decl(implicitIndexSignatures.ts, 4, 5))
+
+map = names2;
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 6, 3))
+>names2 : Symbol(names2, Decl(implicitIndexSignatures.ts, 5, 3))
+
+declare function getStringIndexValue<T>(map: { [x: string]: T }): T;
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>T : Symbol(T, Decl(implicitIndexSignatures.ts, 13, 37))
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 13, 40))
+>x : Symbol(x, Decl(implicitIndexSignatures.ts, 13, 48))
+>T : Symbol(T, Decl(implicitIndexSignatures.ts, 13, 37))
+>T : Symbol(T, Decl(implicitIndexSignatures.ts, 13, 37))
+
+declare function getNumberIndexValue<T>(map: { [x: number]: T }): T;
+>getNumberIndexValue : Symbol(getNumberIndexValue, Decl(implicitIndexSignatures.ts, 13, 68))
+>T : Symbol(T, Decl(implicitIndexSignatures.ts, 14, 37))
+>map : Symbol(map, Decl(implicitIndexSignatures.ts, 14, 40))
+>x : Symbol(x, Decl(implicitIndexSignatures.ts, 14, 48))
+>T : Symbol(T, Decl(implicitIndexSignatures.ts, 14, 37))
+>T : Symbol(T, Decl(implicitIndexSignatures.ts, 14, 37))
+
+function f1() {
+>f1 : Symbol(f1, Decl(implicitIndexSignatures.ts, 14, 68))
+
+    const o1 = { a: 1, b: 2 };
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 17, 9))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 17, 16))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 17, 22))
+
+    let o2: { a: number, b: number };
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 18, 7))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 18, 13))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 18, 24))
+
+    const v1 = getStringIndexValue(o1);
+>v1 : Symbol(v1, Decl(implicitIndexSignatures.ts, 19, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 17, 9))
+
+    const v2 = getStringIndexValue(o2);
+>v2 : Symbol(v2, Decl(implicitIndexSignatures.ts, 20, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 18, 7))
+}
+
+function f2() {
+>f2 : Symbol(f2, Decl(implicitIndexSignatures.ts, 21, 1))
+
+    const o1 = { a: "1", b: "2" };
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 24, 9))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 24, 16))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 24, 24))
+
+    let o2: { a: string, b: string };
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 25, 7))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 25, 13))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 25, 24))
+
+    const v1 = getStringIndexValue(o1);
+>v1 : Symbol(v1, Decl(implicitIndexSignatures.ts, 26, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 24, 9))
+
+    const v2 = getStringIndexValue(o2);
+>v2 : Symbol(v2, Decl(implicitIndexSignatures.ts, 27, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 25, 7))
+}
+
+function f3() {
+>f3 : Symbol(f3, Decl(implicitIndexSignatures.ts, 28, 1))
+
+    const o1 = { a: 1, b: "2" };
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 31, 9))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 31, 16))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 31, 22))
+
+    let o2: { a: number, b: string };
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 32, 7))
+>a : Symbol(a, Decl(implicitIndexSignatures.ts, 32, 13))
+>b : Symbol(b, Decl(implicitIndexSignatures.ts, 32, 24))
+
+    const v1 = getStringIndexValue(o1);
+>v1 : Symbol(v1, Decl(implicitIndexSignatures.ts, 33, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 31, 9))
+
+    const v2 = getStringIndexValue(o2);
+>v2 : Symbol(v2, Decl(implicitIndexSignatures.ts, 34, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 32, 7))
+}
+
+function f4() {
+>f4 : Symbol(f4, Decl(implicitIndexSignatures.ts, 35, 1))
+
+    const o1 = { 0: "0", 1: "1", count: 2 };
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 38, 9))
+>count : Symbol(count, Decl(implicitIndexSignatures.ts, 38, 32))
+
+    let o2: { 0: string, 1: string, count: number };    
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 39, 7))
+>count : Symbol(count, Decl(implicitIndexSignatures.ts, 39, 35))
+
+    const v1 = getStringIndexValue(o1);
+>v1 : Symbol(v1, Decl(implicitIndexSignatures.ts, 40, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 38, 9))
+
+    const v2 = getStringIndexValue(o2);
+>v2 : Symbol(v2, Decl(implicitIndexSignatures.ts, 41, 9))
+>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 39, 7))
+
+    const v3 = getNumberIndexValue(o1);
+>v3 : Symbol(v3, Decl(implicitIndexSignatures.ts, 42, 9))
+>getNumberIndexValue : Symbol(getNumberIndexValue, Decl(implicitIndexSignatures.ts, 13, 68))
+>o1 : Symbol(o1, Decl(implicitIndexSignatures.ts, 38, 9))
+
+    const v4 = getNumberIndexValue(o2);
+>v4 : Symbol(v4, Decl(implicitIndexSignatures.ts, 43, 9))
+>getNumberIndexValue : Symbol(getNumberIndexValue, Decl(implicitIndexSignatures.ts, 13, 68))
+>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 39, 7))
+}
+
diff --git a/tests/baselines/reference/implicitIndexSignatures.types b/tests/baselines/reference/implicitIndexSignatures.types
new file mode 100644
index 00000000000..7d335c00491
--- /dev/null
+++ b/tests/baselines/reference/implicitIndexSignatures.types
@@ -0,0 +1,201 @@
+=== tests/cases/compiler/implicitIndexSignatures.ts ===
+type StringMap = { [x: string]: string };
+>StringMap : { [x: string]: string; }
+>x : string
+
+const empty1 = {};
+>empty1 : {}
+>{} : {}
+
+let empty2: {};
+>empty2 : {}
+
+const names1 = { a: "foo", b: "bar" };
+>names1 : { a: string; b: string; }
+>{ a: "foo", b: "bar" } : { a: string; b: string; }
+>a : string
+>"foo" : string
+>b : string
+>"bar" : string
+
+let names2: { a: string, b: string };
+>names2 : { a: string; b: string; }
+>a : string
+>b : string
+
+let map: StringMap;
+>map : { [x: string]: string; }
+>StringMap : { [x: string]: string; }
+
+map = { x: "xxx", y: "yyy" };
+>map = { x: "xxx", y: "yyy" } : { x: string; y: string; }
+>map : { [x: string]: string; }
+>{ x: "xxx", y: "yyy" } : { x: string; y: string; }
+>x : string
+>"xxx" : string
+>y : string
+>"yyy" : string
+
+map = empty1;
+>map = empty1 : {}
+>map : { [x: string]: string; }
+>empty1 : {}
+
+map = empty2;
+>map = empty2 : {}
+>map : { [x: string]: string; }
+>empty2 : {}
+
+map = names1;
+>map = names1 : { a: string; b: string; }
+>map : { [x: string]: string; }
+>names1 : { a: string; b: string; }
+
+map = names2;
+>map = names2 : { a: string; b: string; }
+>map : { [x: string]: string; }
+>names2 : { a: string; b: string; }
+
+declare function getStringIndexValue<T>(map: { [x: string]: T }): T;
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>T : T
+>map : { [x: string]: T; }
+>x : string
+>T : T
+>T : T
+
+declare function getNumberIndexValue<T>(map: { [x: number]: T }): T;
+>getNumberIndexValue : <T>(map: { [x: number]: T; }) => T
+>T : T
+>map : { [x: number]: T; }
+>x : number
+>T : T
+>T : T
+
+function f1() {
+>f1 : () => void
+
+    const o1 = { a: 1, b: 2 };
+>o1 : { a: number; b: number; }
+>{ a: 1, b: 2 } : { a: number; b: number; }
+>a : number
+>1 : number
+>b : number
+>2 : number
+
+    let o2: { a: number, b: number };
+>o2 : { a: number; b: number; }
+>a : number
+>b : number
+
+    const v1 = getStringIndexValue(o1);
+>v1 : number
+>getStringIndexValue(o1) : number
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o1 : { a: number; b: number; }
+
+    const v2 = getStringIndexValue(o2);
+>v2 : number
+>getStringIndexValue(o2) : number
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o2 : { a: number; b: number; }
+}
+
+function f2() {
+>f2 : () => void
+
+    const o1 = { a: "1", b: "2" };
+>o1 : { a: string; b: string; }
+>{ a: "1", b: "2" } : { a: string; b: string; }
+>a : string
+>"1" : string
+>b : string
+>"2" : string
+
+    let o2: { a: string, b: string };
+>o2 : { a: string; b: string; }
+>a : string
+>b : string
+
+    const v1 = getStringIndexValue(o1);
+>v1 : string
+>getStringIndexValue(o1) : string
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o1 : { a: string; b: string; }
+
+    const v2 = getStringIndexValue(o2);
+>v2 : string
+>getStringIndexValue(o2) : string
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o2 : { a: string; b: string; }
+}
+
+function f3() {
+>f3 : () => void
+
+    const o1 = { a: 1, b: "2" };
+>o1 : { a: number; b: string; }
+>{ a: 1, b: "2" } : { a: number; b: string; }
+>a : number
+>1 : number
+>b : string
+>"2" : string
+
+    let o2: { a: number, b: string };
+>o2 : { a: number; b: string; }
+>a : number
+>b : string
+
+    const v1 = getStringIndexValue(o1);
+>v1 : number | string
+>getStringIndexValue(o1) : number | string
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o1 : { a: number; b: string; }
+
+    const v2 = getStringIndexValue(o2);
+>v2 : number | string
+>getStringIndexValue(o2) : number | string
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o2 : { a: number; b: string; }
+}
+
+function f4() {
+>f4 : () => void
+
+    const o1 = { 0: "0", 1: "1", count: 2 };
+>o1 : { 0: string; 1: string; count: number; }
+>{ 0: "0", 1: "1", count: 2 } : { 0: string; 1: string; count: number; }
+>"0" : string
+>"1" : string
+>count : number
+>2 : number
+
+    let o2: { 0: string, 1: string, count: number };    
+>o2 : { 0: string; 1: string; count: number; }
+>count : number
+
+    const v1 = getStringIndexValue(o1);
+>v1 : string | number
+>getStringIndexValue(o1) : string | number
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o1 : { 0: string; 1: string; count: number; }
+
+    const v2 = getStringIndexValue(o2);
+>v2 : string | number
+>getStringIndexValue(o2) : string | number
+>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
+>o2 : { 0: string; 1: string; count: number; }
+
+    const v3 = getNumberIndexValue(o1);
+>v3 : string
+>getNumberIndexValue(o1) : string
+>getNumberIndexValue : <T>(map: { [x: number]: T; }) => T
+>o1 : { 0: string; 1: string; count: number; }
+
+    const v4 = getNumberIndexValue(o2);
+>v4 : string
+>getNumberIndexValue(o2) : string
+>getNumberIndexValue : <T>(map: { [x: number]: T; }) => T
+>o2 : { 0: string; 1: string; count: number; }
+}
+
diff --git a/tests/baselines/reference/indexSignaturesInferentialTyping.types b/tests/baselines/reference/indexSignaturesInferentialTyping.types
index 328dbc18e4f..8545a7d4ca9 100644
--- a/tests/baselines/reference/indexSignaturesInferentialTyping.types
+++ b/tests/baselines/reference/indexSignaturesInferentialTyping.types
@@ -21,15 +21,15 @@ var x1 = foo({ 0: 0, 1: 1 });       // type should be number
 >x1 : number
 >foo({ 0: 0, 1: 1 }) : number
 >foo : <T>(items: { [index: number]: T; }) => T
->{ 0: 0, 1: 1 } : { [x: number]: number; 0: number; 1: number; }
+>{ 0: 0, 1: 1 } : { 0: number; 1: number; }
 >0 : number
 >1 : number
 
 var x2 = foo({ zero: 0, one: 1 });
->x2 : any
->foo({ zero: 0, one: 1 }) : any
+>x2 : {}
+>foo({ zero: 0, one: 1 }) : {}
 >foo : <T>(items: { [index: number]: T; }) => T
->{ zero: 0, one: 1 } : { [x: number]: undefined; zero: number; one: number; }
+>{ zero: 0, one: 1 } : { zero: number; one: number; }
 >zero : number
 >0 : number
 >one : number
@@ -39,7 +39,7 @@ var x3 = bar({ 0: 0, 1: 1 });
 >x3 : number
 >bar({ 0: 0, 1: 1 }) : number
 >bar : <T>(items: { [index: string]: T; }) => T
->{ 0: 0, 1: 1 } : { [x: string]: number; 0: number; 1: number; }
+>{ 0: 0, 1: 1 } : { 0: number; 1: number; }
 >0 : number
 >1 : number
 
@@ -47,7 +47,7 @@ var x4 = bar({ zero: 0, one: 1 });  // type should be number
 >x4 : number
 >bar({ zero: 0, one: 1 }) : number
 >bar : <T>(items: { [index: string]: T; }) => T
->{ zero: 0, one: 1 } : { [x: string]: number; zero: number; one: number; }
+>{ zero: 0, one: 1 } : { zero: number; one: number; }
 >zero : number
 >0 : number
 >one : number
diff --git a/tests/baselines/reference/indexer.types b/tests/baselines/reference/indexer.types
index a0142bb9383..f24c90f6ea1 100644
--- a/tests/baselines/reference/indexer.types
+++ b/tests/baselines/reference/indexer.types
@@ -17,7 +17,7 @@ interface JQuery {
 var jq:JQuery={ 0: { id : "a" }, 1: { id : "b" } };
 >jq : JQuery
 >JQuery : JQuery
->{ 0: { id : "a" }, 1: { id : "b" } } : { [x: number]: { id: string; }; 0: { id: string; }; 1: { id: string; }; }
+>{ 0: { id : "a" }, 1: { id : "b" } } : { 0: { id: string; }; 1: { id: string; }; }
 >{ id : "a" } : { id: string; }
 >id : string
 >"a" : string
diff --git a/tests/baselines/reference/indexer2.types b/tests/baselines/reference/indexer2.types
index 7f1ccd41cb5..ff82707edd3 100644
--- a/tests/baselines/reference/indexer2.types
+++ b/tests/baselines/reference/indexer2.types
@@ -17,5 +17,5 @@ var directChildrenMap = <IDirectChildrenMap>{};
 >directChildrenMap : IDirectChildrenMap
 ><IDirectChildrenMap>{} : IDirectChildrenMap
 >IDirectChildrenMap : IDirectChildrenMap
->{} : { [x: number]: undefined; }
+>{} : {}
 
diff --git a/tests/baselines/reference/indexer3.types b/tests/baselines/reference/indexer3.types
index 8f0582f782a..28bcd9cab0c 100644
--- a/tests/baselines/reference/indexer3.types
+++ b/tests/baselines/reference/indexer3.types
@@ -3,7 +3,7 @@ var dateMap: { [x: string]: Date; } = {}
 >dateMap : { [x: string]: Date; }
 >x : string
 >Date : Date
->{} : { [x: string]: undefined; }
+>{} : {}
 
 var r: Date = dateMap["hello"] // result type includes indexer using BCT
 >r : Date
diff --git a/tests/baselines/reference/indexerA.types b/tests/baselines/reference/indexerA.types
index c6ff81b3a26..ee6351eae33 100644
--- a/tests/baselines/reference/indexerA.types
+++ b/tests/baselines/reference/indexerA.types
@@ -17,7 +17,7 @@ class JQuery {
 var jq:JQuery={ 0: { id : "a" }, 1: { id : "b" } };
 >jq : JQuery
 >JQuery : JQuery
->{ 0: { id : "a" }, 1: { id : "b" } } : { [x: number]: { id: string; }; 0: { id: string; }; 1: { id: string; }; }
+>{ 0: { id : "a" }, 1: { id : "b" } } : { 0: { id: string; }; 1: { id: string; }; }
 >{ id : "a" } : { id: string; }
 >id : string
 >"a" : string
diff --git a/tests/baselines/reference/indexerAssignability.errors.txt b/tests/baselines/reference/indexerAssignability.errors.txt
deleted file mode 100644
index 44c2184517e..00000000000
--- a/tests/baselines/reference/indexerAssignability.errors.txt
+++ /dev/null
@@ -1,28 +0,0 @@
-tests/cases/compiler/indexerAssignability.ts(5,1): error TS2322: Type '{ [n: number]: string; }' is not assignable to type '{ [s: string]: string; }'.
-  Index signature is missing in type '{ [n: number]: string; }'.
-tests/cases/compiler/indexerAssignability.ts(6,1): error TS2322: Type '{}' is not assignable to type '{ [s: string]: string; }'.
-  Index signature is missing in type '{}'.
-tests/cases/compiler/indexerAssignability.ts(8,1): error TS2322: Type '{}' is not assignable to type '{ [n: number]: string; }'.
-  Index signature is missing in type '{}'.
-
-
-==== tests/cases/compiler/indexerAssignability.ts (3 errors) ====
-    var a: { [s: string]: string; };
-    var b: { [n: number]: string; };
-    var c: {};
-    
-    a = b;
-    ~
-!!! error TS2322: Type '{ [n: number]: string; }' is not assignable to type '{ [s: string]: string; }'.
-!!! error TS2322:   Index signature is missing in type '{ [n: number]: string; }'.
-    a = c;
-    ~
-!!! error TS2322: Type '{}' is not assignable to type '{ [s: string]: string; }'.
-!!! error TS2322:   Index signature is missing in type '{}'.
-    b = a;
-    b = c;
-    ~
-!!! error TS2322: Type '{}' is not assignable to type '{ [n: number]: string; }'.
-!!! error TS2322:   Index signature is missing in type '{}'.
-    c = a;
-    c = b;
\ No newline at end of file
diff --git a/tests/baselines/reference/indexerAssignability.symbols b/tests/baselines/reference/indexerAssignability.symbols
new file mode 100644
index 00000000000..379a2885e2c
--- /dev/null
+++ b/tests/baselines/reference/indexerAssignability.symbols
@@ -0,0 +1,36 @@
+=== tests/cases/compiler/indexerAssignability.ts ===
+var a: { [s: string]: string; };
+>a : Symbol(a, Decl(indexerAssignability.ts, 0, 3))
+>s : Symbol(s, Decl(indexerAssignability.ts, 0, 10))
+
+var b: { [n: number]: string; };
+>b : Symbol(b, Decl(indexerAssignability.ts, 1, 3))
+>n : Symbol(n, Decl(indexerAssignability.ts, 1, 10))
+
+var c: {};
+>c : Symbol(c, Decl(indexerAssignability.ts, 2, 3))
+
+a = b;
+>a : Symbol(a, Decl(indexerAssignability.ts, 0, 3))
+>b : Symbol(b, Decl(indexerAssignability.ts, 1, 3))
+
+a = c;
+>a : Symbol(a, Decl(indexerAssignability.ts, 0, 3))
+>c : Symbol(c, Decl(indexerAssignability.ts, 2, 3))
+
+b = a;
+>b : Symbol(b, Decl(indexerAssignability.ts, 1, 3))
+>a : Symbol(a, Decl(indexerAssignability.ts, 0, 3))
+
+b = c;
+>b : Symbol(b, Decl(indexerAssignability.ts, 1, 3))
+>c : Symbol(c, Decl(indexerAssignability.ts, 2, 3))
+
+c = a;
+>c : Symbol(c, Decl(indexerAssignability.ts, 2, 3))
+>a : Symbol(a, Decl(indexerAssignability.ts, 0, 3))
+
+c = b;
+>c : Symbol(c, Decl(indexerAssignability.ts, 2, 3))
+>b : Symbol(b, Decl(indexerAssignability.ts, 1, 3))
+
diff --git a/tests/baselines/reference/indexerAssignability.types b/tests/baselines/reference/indexerAssignability.types
new file mode 100644
index 00000000000..bd301b59224
--- /dev/null
+++ b/tests/baselines/reference/indexerAssignability.types
@@ -0,0 +1,42 @@
+=== tests/cases/compiler/indexerAssignability.ts ===
+var a: { [s: string]: string; };
+>a : { [s: string]: string; }
+>s : string
+
+var b: { [n: number]: string; };
+>b : { [n: number]: string; }
+>n : number
+
+var c: {};
+>c : {}
+
+a = b;
+>a = b : { [n: number]: string; }
+>a : { [s: string]: string; }
+>b : { [n: number]: string; }
+
+a = c;
+>a = c : {}
+>a : { [s: string]: string; }
+>c : {}
+
+b = a;
+>b = a : { [s: string]: string; }
+>b : { [n: number]: string; }
+>a : { [s: string]: string; }
+
+b = c;
+>b = c : {}
+>b : { [n: number]: string; }
+>c : {}
+
+c = a;
+>c = a : { [s: string]: string; }
+>c : {}
+>a : { [s: string]: string; }
+
+c = b;
+>c = b : { [n: number]: string; }
+>c : {}
+>b : { [n: number]: string; }
+
diff --git a/tests/baselines/reference/inferentialTypingObjectLiteralMethod2.types b/tests/baselines/reference/inferentialTypingObjectLiteralMethod2.types
index be937410cef..f70305739b8 100644
--- a/tests/baselines/reference/inferentialTypingObjectLiteralMethod2.types
+++ b/tests/baselines/reference/inferentialTypingObjectLiteralMethod2.types
@@ -30,13 +30,13 @@ foo("", { method(p1) { return p1.length } }, { method(p2) { return undefined } }
 >foo("", { method(p1) { return p1.length } }, { method(p2) { return undefined } }) : string
 >foo : <T, U>(x: T, y: Int<T, U>, z: Int<U, T>) => T
 >"" : string
->{ method(p1) { return p1.length } } : { [x: string]: (p1: string) => number; method(p1: string): number; }
+>{ method(p1) { return p1.length } } : { method(p1: string): number; }
 >method : (p1: string) => number
 >p1 : string
 >p1.length : number
 >p1 : string
 >length : number
->{ method(p2) { return undefined } } : { [x: string]: (p2: number) => any; method(p2: number): any; }
+>{ method(p2) { return undefined } } : { method(p2: number): any; }
 >method : (p2: number) => any
 >p2 : number
 >undefined : undefined
diff --git a/tests/baselines/reference/inferentialTypingUsingApparentType3.types b/tests/baselines/reference/inferentialTypingUsingApparentType3.types
index 9e0a4ceaea6..e375fe981e8 100644
--- a/tests/baselines/reference/inferentialTypingUsingApparentType3.types
+++ b/tests/baselines/reference/inferentialTypingUsingApparentType3.types
@@ -49,10 +49,10 @@ class ObjectField<A, T extends { [name: string]: Field<any> }> {
 }
 
 var person = new ObjectField({
->person : ObjectField<{}, { [x: string]: NumberField | CharField; id: NumberField; name: CharField; }>
->new ObjectField({    id: new NumberField(),    name: new CharField()}) : ObjectField<{}, { [x: string]: NumberField | CharField; id: NumberField; name: CharField; }>
+>person : ObjectField<{}, { id: NumberField; name: CharField; }>
+>new ObjectField({    id: new NumberField(),    name: new CharField()}) : ObjectField<{}, { id: NumberField; name: CharField; }>
 >ObjectField : typeof ObjectField
->{    id: new NumberField(),    name: new CharField()} : { [x: string]: NumberField | CharField; id: NumberField; name: CharField; }
+>{    id: new NumberField(),    name: new CharField()} : { id: NumberField; name: CharField; }
 
     id: new NumberField(),
 >id : NumberField
@@ -68,8 +68,8 @@ var person = new ObjectField({
 
 person.fields.id;
 >person.fields.id : NumberField
->person.fields : { [x: string]: NumberField | CharField; id: NumberField; name: CharField; }
->person : ObjectField<{}, { [x: string]: NumberField | CharField; id: NumberField; name: CharField; }>
->fields : { [x: string]: NumberField | CharField; id: NumberField; name: CharField; }
+>person.fields : { id: NumberField; name: CharField; }
+>person : ObjectField<{}, { id: NumberField; name: CharField; }>
+>fields : { id: NumberField; name: CharField; }
 >id : NumberField
 
diff --git a/tests/baselines/reference/interfaceContextualType.types b/tests/baselines/reference/interfaceContextualType.types
index e827f9a9d9b..0e835a2f1f9 100644
--- a/tests/baselines/reference/interfaceContextualType.types
+++ b/tests/baselines/reference/interfaceContextualType.types
@@ -27,11 +27,11 @@ class Bug {
 >ok : () => void
 
         this.values = {};
->this.values = {} : { [x: string]: undefined; }
+>this.values = {} : {}
 >this.values : IMap
 >this : this
 >values : IMap
->{} : { [x: string]: undefined; }
+>{} : {}
 
         this.values['comments'] = { italic: true };
 >this.values['comments'] = { italic: true } : { italic: boolean; }
@@ -48,11 +48,11 @@ class Bug {
 >shouldBeOK : () => void
 
         this.values = {
->this.values = {            comments: { italic: true }        } : { [x: string]: { italic: boolean; }; comments: { italic: boolean; }; }
+>this.values = {            comments: { italic: true }        } : { comments: { italic: boolean; }; }
 >this.values : IMap
 >this : this
 >values : IMap
->{            comments: { italic: true }        } : { [x: string]: { italic: boolean; }; comments: { italic: boolean; }; }
+>{            comments: { italic: true }        } : { comments: { italic: boolean; }; }
 
             comments: { italic: true }
 >comments : { italic: boolean; }
diff --git a/tests/baselines/reference/isArray.types b/tests/baselines/reference/isArray.types
index de54e9d064c..bc452b12bef 100644
--- a/tests/baselines/reference/isArray.types
+++ b/tests/baselines/reference/isArray.types
@@ -4,7 +4,7 @@ var maybeArray: number | number[];
 
 
 if (Array.isArray(maybeArray)) {
->Array.isArray(maybeArray) : arg is any[]
+>Array.isArray(maybeArray) : boolean
 >Array.isArray : (arg: any) => arg is any[]
 >Array : ArrayConstructor
 >isArray : (arg: any) => arg is any[]
diff --git a/tests/baselines/reference/jsFileCompilationDecoratorSyntax.errors.txt b/tests/baselines/reference/jsFileCompilationDecoratorSyntax.errors.txt
deleted file mode 100644
index a39d2e1665c..00000000000
--- a/tests/baselines/reference/jsFileCompilationDecoratorSyntax.errors.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
-tests/cases/compiler/a.js(1,1): error TS8017: 'decorators' can only be used in a .ts file.
-
-
-!!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
-==== tests/cases/compiler/a.js (1 errors) ====
-    @internal class C { }
-    ~~~~~~~~~
-!!! error TS8017: 'decorators' can only be used in a .ts file.
\ No newline at end of file
diff --git a/tests/baselines/reference/jsFileCompilationDecoratorSyntax.symbols b/tests/baselines/reference/jsFileCompilationDecoratorSyntax.symbols
new file mode 100644
index 00000000000..02973b43147
--- /dev/null
+++ b/tests/baselines/reference/jsFileCompilationDecoratorSyntax.symbols
@@ -0,0 +1,4 @@
+=== tests/cases/compiler/a.js ===
+@internal class C { }
+>C : Symbol(C, Decl(a.js, 0, 0))
+
diff --git a/tests/baselines/reference/jsFileCompilationDecoratorSyntax.types b/tests/baselines/reference/jsFileCompilationDecoratorSyntax.types
new file mode 100644
index 00000000000..ee1f14129d5
--- /dev/null
+++ b/tests/baselines/reference/jsFileCompilationDecoratorSyntax.types
@@ -0,0 +1,5 @@
+=== tests/cases/compiler/a.js ===
+@internal class C { }
+>internal : any
+>C : C
+
diff --git a/tests/baselines/reference/noErrorsInCallback.errors.txt b/tests/baselines/reference/noErrorsInCallback.errors.txt
index 90fdbbd77a5..f0bfe00199e 100644
--- a/tests/baselines/reference/noErrorsInCallback.errors.txt
+++ b/tests/baselines/reference/noErrorsInCallback.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/noErrorsInCallback.ts(4,19): error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'string'.
-tests/cases/compiler/noErrorsInCallback.ts(6,23): error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'string'.
+tests/cases/compiler/noErrorsInCallback.ts(4,19): error TS2345: Argument of type '{}' is not assignable to parameter of type 'string'.
+tests/cases/compiler/noErrorsInCallback.ts(6,23): error TS2345: Argument of type '{}' is not assignable to parameter of type 'string'.
 
 
 ==== tests/cases/compiler/noErrorsInCallback.ts (2 errors) ====
@@ -8,10 +8,10 @@ tests/cases/compiler/noErrorsInCallback.ts(6,23): error TS2345: Argument of type
     }
     var one = new Bar({}); // Error
                       ~~
-!!! error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'string'.
+!!! error TS2345: Argument of type '{}' is not assignable to parameter of type 'string'.
     [].forEach(() => {
         var two = new Bar({}); // No error?
                           ~~
-!!! error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'string'.
+!!! error TS2345: Argument of type '{}' is not assignable to parameter of type 'string'.
     });
      
\ No newline at end of file
diff --git a/tests/baselines/reference/noImplicitAnyIndexingSuppressed.types b/tests/baselines/reference/noImplicitAnyIndexingSuppressed.types
index b7b21bf8f92..d82b37e0f9e 100644
--- a/tests/baselines/reference/noImplicitAnyIndexingSuppressed.types
+++ b/tests/baselines/reference/noImplicitAnyIndexingSuppressed.types
@@ -87,7 +87,7 @@ interface MyMap<T> {
 var m: MyMap<number> = {
 >m : MyMap<number>
 >MyMap : MyMap<T>
->{    "0": 0,    "1": 1,    "2": 2,    "Okay that's enough for today.": NaN} : { [x: string]: number; "0": number; "1": number; "2": number; "Okay that's enough for today.": number; }
+>{    "0": 0,    "1": 1,    "2": 2,    "Okay that's enough for today.": NaN} : { "0": number; "1": number; "2": number; "Okay that's enough for today.": number; }
 
     "0": 0,
 >0 : number
diff --git a/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations.errors.txt b/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations.errors.txt
index 35673eb3072..bb01b2fe125 100644
--- a/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations.errors.txt
+++ b/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations.errors.txt
@@ -5,10 +5,9 @@ tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerCo
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(36,16): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(50,5): error TS2412: Property '2.0' of type 'number' is not assignable to numeric index type 'string'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(68,5): error TS2412: Property '2.0' of type 'number' is not assignable to numeric index type 'string'.
-tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(78,5): error TS2322: Type '{ [x: number]: string | number; 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: any; X: string; foo(): string; }' is not assignable to type '{ [x: number]: string; }'.
-  Index signatures are incompatible.
-    Type 'string | number' is not assignable to type 'string'.
-      Type 'number' is not assignable to type 'string'.
+tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(78,5): error TS2322: Type '{ 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: any; X: string; foo(): string; }' is not assignable to type '{ [x: number]: string; }'.
+  Property '2.0' is incompatible with index signature.
+    Type 'number' is not assignable to type 'string'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(88,9): error TS2304: Cannot find name 'Myn'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(90,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations.ts(93,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -108,10 +107,9 @@ tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerCo
     // error
     var b: { [x: number]: string; } = {
         ~
-!!! error TS2322: Type '{ [x: number]: string | number; 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: any; X: string; foo(): string; }' is not assignable to type '{ [x: number]: string; }'.
-!!! error TS2322:   Index signatures are incompatible.
-!!! error TS2322:     Type 'string | number' is not assignable to type 'string'.
-!!! error TS2322:       Type 'number' is not assignable to type 'string'.
+!!! error TS2322: Type '{ 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: any; X: string; foo(): string; }' is not assignable to type '{ [x: number]: string; }'.
+!!! error TS2322:   Property '2.0' is incompatible with index signature.
+!!! error TS2322:     Type 'number' is not assignable to type 'string'.
         a: '',
         b: 1, 
         c: () => { }, 
diff --git a/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.errors.txt b/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.errors.txt
index ff18160e9a5..332b356c732 100644
--- a/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.errors.txt
+++ b/tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations2.errors.txt
@@ -1,10 +1,9 @@
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations2.ts(16,5): error TS2412: Property '3.0' of type 'number' is not assignable to numeric index type 'A'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations2.ts(25,5): error TS2412: Property '3.0' of type 'number' is not assignable to numeric index type 'A'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations2.ts(34,5): error TS2412: Property '3.0' of type 'number' is not assignable to numeric index type 'A'.
-tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations2.ts(39,5): error TS2322: Type '{ [x: number]: A | number; 1.0: A; 2.0: B; 3.0: number; "2.5": B; "4.0": string; }' is not assignable to type '{ [x: number]: A; }'.
-  Index signatures are incompatible.
-    Type 'A | number' is not assignable to type 'A'.
-      Type 'number' is not assignable to type 'A'.
+tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations2.ts(39,5): error TS2322: Type '{ 1.0: A; 2.0: B; 3.0: number; "2.5": B; "4.0": string; }' is not assignable to type '{ [x: number]: A; }'.
+  Property '3.0' is incompatible with index signature.
+    Type 'number' is not assignable to type 'A'.
 
 
 ==== tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerConstrainsPropertyDeclarations2.ts (4 errors) ====
@@ -54,10 +53,9 @@ tests/cases/conformance/types/objectTypeLiteral/indexSignatures/numericIndexerCo
     // error
     var b: { [x: number]: A } = {
         ~
-!!! error TS2322: Type '{ [x: number]: A | number; 1.0: A; 2.0: B; 3.0: number; "2.5": B; "4.0": string; }' is not assignable to type '{ [x: number]: A; }'.
-!!! error TS2322:   Index signatures are incompatible.
-!!! error TS2322:     Type 'A | number' is not assignable to type 'A'.
-!!! error TS2322:       Type 'number' is not assignable to type 'A'.
+!!! error TS2322: Type '{ 1.0: A; 2.0: B; 3.0: number; "2.5": B; "4.0": string; }' is not assignable to type '{ [x: number]: A; }'.
+!!! error TS2322:   Property '3.0' is incompatible with index signature.
+!!! error TS2322:     Type 'number' is not assignable to type 'A'.
         1.0: new A(), 
         2.0: new B(), 
         "2.5": new B(),
diff --git a/tests/baselines/reference/numericIndexerConstraint2.errors.txt b/tests/baselines/reference/numericIndexerConstraint2.errors.txt
index 385efbcead2..5c0337acc32 100644
--- a/tests/baselines/reference/numericIndexerConstraint2.errors.txt
+++ b/tests/baselines/reference/numericIndexerConstraint2.errors.txt
@@ -1,5 +1,6 @@
 tests/cases/compiler/numericIndexerConstraint2.ts(4,1): error TS2322: Type '{ one: number; }' is not assignable to type '{ [index: string]: Foo; }'.
-  Index signature is missing in type '{ one: number; }'.
+  Property 'one' is incompatible with index signature.
+    Type 'number' is not assignable to type 'Foo'.
 
 
 ==== tests/cases/compiler/numericIndexerConstraint2.ts (1 errors) ====
@@ -9,4 +10,5 @@ tests/cases/compiler/numericIndexerConstraint2.ts(4,1): error TS2322: Type '{ on
     x = a;
     ~
 !!! error TS2322: Type '{ one: number; }' is not assignable to type '{ [index: string]: Foo; }'.
-!!! error TS2322:   Index signature is missing in type '{ one: number; }'.
\ No newline at end of file
+!!! error TS2322:   Property 'one' is incompatible with index signature.
+!!! error TS2322:     Type 'number' is not assignable to type 'Foo'.
\ No newline at end of file
diff --git a/tests/baselines/reference/numericIndexerConstraint4.types b/tests/baselines/reference/numericIndexerConstraint4.types
index 97e72b5088d..c8af4d54a9a 100644
--- a/tests/baselines/reference/numericIndexerConstraint4.types
+++ b/tests/baselines/reference/numericIndexerConstraint4.types
@@ -22,7 +22,7 @@ var x: {
 >A : A
 
 } = { data: new B() }
->{ data: new B() } : { [x: number]: undefined; data: B; }
+>{ data: new B() } : { data: B; }
 >data : B
 >new B() : B
 >B : typeof B
diff --git a/tests/baselines/reference/numericIndexerConstraint5.errors.txt b/tests/baselines/reference/numericIndexerConstraint5.errors.txt
index 98acc65eeb7..cb888de08c4 100644
--- a/tests/baselines/reference/numericIndexerConstraint5.errors.txt
+++ b/tests/baselines/reference/numericIndexerConstraint5.errors.txt
@@ -1,5 +1,6 @@
 tests/cases/compiler/numericIndexerConstraint5.ts(2,5): error TS2322: Type '{ 0: Date; name: string; }' is not assignable to type '{ [name: number]: string; }'.
-  Index signature is missing in type '{ 0: Date; name: string; }'.
+  Property '0' is incompatible with index signature.
+    Type 'Date' is not assignable to type 'string'.
 
 
 ==== tests/cases/compiler/numericIndexerConstraint5.ts (1 errors) ====
@@ -7,4 +8,5 @@ tests/cases/compiler/numericIndexerConstraint5.ts(2,5): error TS2322: Type '{ 0:
     var z: { [name: number]: string } = x;
         ~
 !!! error TS2322: Type '{ 0: Date; name: string; }' is not assignable to type '{ [name: number]: string; }'.
-!!! error TS2322:   Index signature is missing in type '{ 0: Date; name: string; }'.
\ No newline at end of file
+!!! error TS2322:   Property '0' is incompatible with index signature.
+!!! error TS2322:     Type 'Date' is not assignable to type 'string'.
\ No newline at end of file
diff --git a/tests/baselines/reference/numericIndexingResults.types b/tests/baselines/reference/numericIndexingResults.types
index 560bbdc74a8..9a060b388e3 100644
--- a/tests/baselines/reference/numericIndexingResults.types
+++ b/tests/baselines/reference/numericIndexingResults.types
@@ -151,7 +151,7 @@ var r6 = a[3];
 var b: { [x: number]: string } = { 1: '', "2": '' }
 >b : { [x: number]: string; }
 >x : number
->{ 1: '', "2": '' } : { [x: number]: string; 1: string; "2": string; }
+>{ 1: '', "2": '' } : { 1: string; "2": string; }
 >'' : string
 >'' : string
 
@@ -194,7 +194,7 @@ var r6 = b[3];
 var b2: { [x: number]: string; 1: string; "2": string; } = { 1: '', "2": '' }
 >b2 : { [x: number]: string; 1: string; "2": string; }
 >x : number
->{ 1: '', "2": '' } : { [x: number]: string; 1: string; "2": string; }
+>{ 1: '', "2": '' } : { 1: string; "2": string; }
 >'' : string
 >'' : string
 
diff --git a/tests/baselines/reference/objectIndexer.types b/tests/baselines/reference/objectIndexer.types
index 3dcd7bcb77e..b11c475a386 100644
--- a/tests/baselines/reference/objectIndexer.types
+++ b/tests/baselines/reference/objectIndexer.types
@@ -23,11 +23,11 @@ class Emitter {
 
     constructor () {
         this.listeners = {};
->this.listeners = {} : { [x: string]: undefined; }
+>this.listeners = {} : {}
 >this.listeners : IMap
 >this : this
 >listeners : IMap
->{} : { [x: string]: undefined; }
+>{} : {}
     }
 }
 
diff --git a/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt b/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt
index f825c416311..9d5ff7ea0a2 100644
--- a/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt
+++ b/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt
@@ -1,10 +1,13 @@
-tests/cases/compiler/objectLiteralIndexerErrors.ts(13,5): error TS2322: Type '{ [x: string]: A; [x: number]: A; 0: A; x: B; }' is not assignable to type '{ [s: string]: A; [n: number]: B; }'.
-  Index signatures are incompatible.
+tests/cases/compiler/objectLiteralIndexerErrors.ts(13,5): error TS2322: Type '{ 0: A; x: B; }' is not assignable to type '{ [s: string]: A; [n: number]: B; }'.
+  Property '0' is incompatible with index signature.
     Type 'A' is not assignable to type 'B'.
       Property 'y' is missing in type 'A'.
+tests/cases/compiler/objectLiteralIndexerErrors.ts(14,1): error TS2322: Type '{ 0: A; x: any; }' is not assignable to type '{ [s: string]: A; [n: number]: B; }'.
+  Property '0' is incompatible with index signature.
+    Type 'A' is not assignable to type 'B'.
 
 
-==== tests/cases/compiler/objectLiteralIndexerErrors.ts (1 errors) ====
+==== tests/cases/compiler/objectLiteralIndexerErrors.ts (2 errors) ====
     interface A {
         x: number;
     }
@@ -19,8 +22,12 @@ tests/cases/compiler/objectLiteralIndexerErrors.ts(13,5): error TS2322: Type '{
     
     var o1: { [s: string]: A;[n: number]: B; } = { x: b, 0: a }; // both indexers are A
         ~~
-!!! error TS2322: Type '{ [x: string]: A; [x: number]: A; 0: A; x: B; }' is not assignable to type '{ [s: string]: A; [n: number]: B; }'.
-!!! error TS2322:   Index signatures are incompatible.
+!!! error TS2322: Type '{ 0: A; x: B; }' is not assignable to type '{ [s: string]: A; [n: number]: B; }'.
+!!! error TS2322:   Property '0' is incompatible with index signature.
 !!! error TS2322:     Type 'A' is not assignable to type 'B'.
 !!! error TS2322:       Property 'y' is missing in type 'A'.
-    o1 = { x: c, 0: a }; // string indexer is any, number indexer is A
\ No newline at end of file
+    o1 = { x: c, 0: a }; // string indexer is any, number indexer is A
+    ~~
+!!! error TS2322: Type '{ 0: A; x: any; }' is not assignable to type '{ [s: string]: A; [n: number]: B; }'.
+!!! error TS2322:   Property '0' is incompatible with index signature.
+!!! error TS2322:     Type 'A' is not assignable to type 'B'.
\ No newline at end of file
diff --git a/tests/baselines/reference/objectLiteralIndexerNoImplicitAny.types b/tests/baselines/reference/objectLiteralIndexerNoImplicitAny.types
index a49f76d02e9..b0ddd9f60d0 100644
--- a/tests/baselines/reference/objectLiteralIndexerNoImplicitAny.types
+++ b/tests/baselines/reference/objectLiteralIndexerNoImplicitAny.types
@@ -9,7 +9,7 @@ interface I {
 var x: I = {
 >x : I
 >I : I
->{    p: null} : { [x: string]: null; p: null; }
+>{    p: null} : { p: null; }
 
     p: null
 >p : null
diff --git a/tests/baselines/reference/objectLiteralIndexers.types b/tests/baselines/reference/objectLiteralIndexers.types
index d5add00ebaf..9e3aa4bac49 100644
--- a/tests/baselines/reference/objectLiteralIndexers.types
+++ b/tests/baselines/reference/objectLiteralIndexers.types
@@ -31,23 +31,23 @@ var o1: { [s: string]: A;[n: number]: B; } = { x: a, 0: b }; // string indexer i
 >A : A
 >n : number
 >B : B
->{ x: a, 0: b } : { [x: string]: A; [x: number]: B; 0: B; x: A; }
+>{ x: a, 0: b } : { 0: B; x: A; }
 >x : A
 >a : A
 >b : B
 
 o1 = { x: b, 0: c }; // both indexers are any
->o1 = { x: b, 0: c } : { [x: string]: any; [x: number]: any; 0: any; x: B; }
+>o1 = { x: b, 0: c } : { 0: any; x: B; }
 >o1 : { [s: string]: A; [n: number]: B; }
->{ x: b, 0: c } : { [x: string]: any; [x: number]: any; 0: any; x: B; }
+>{ x: b, 0: c } : { 0: any; x: B; }
 >x : B
 >b : B
 >c : any
 
 o1 = { x: c, 0: b }; // string indexer is any, number indexer is B
->o1 = { x: c, 0: b } : { [x: string]: any; [x: number]: B; 0: B; x: any; }
+>o1 = { x: c, 0: b } : { 0: B; x: any; }
 >o1 : { [s: string]: A; [n: number]: B; }
->{ x: c, 0: b } : { [x: string]: any; [x: number]: B; 0: B; x: any; }
+>{ x: c, 0: b } : { 0: B; x: any; }
 >x : any
 >c : any
 >b : B
diff --git a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.types b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.types
index 2284d06ffbd..c5de5c7b9b4 100644
--- a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.types
+++ b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers1.types
@@ -50,7 +50,7 @@ var a: {
 var b: { [x: number]: string; } = { foo: '' };
 >b : { [x: number]: string; }
 >x : number
->{ foo: '' } : { [x: number]: undefined; foo: string; }
+>{ foo: '' } : { foo: string; }
 >foo : string
 >'' : string
 
diff --git a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.types b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.types
index 1a580297b1b..17fc6a07a00 100644
--- a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.types
+++ b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers2.types
@@ -64,7 +64,7 @@ var b: { [x: number]: Derived; } = { foo: <Derived>null };
 >b : { [x: number]: Derived; }
 >x : number
 >Derived : Derived
->{ foo: <Derived>null } : { [x: number]: undefined; foo: Derived; }
+>{ foo: <Derived>null } : { foo: Derived; }
 >foo : Derived
 ><Derived>null : Derived
 >Derived : Derived
diff --git a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.types b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.types
index ae384bbb4db..99e6b8c8632 100644
--- a/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.types
+++ b/tests/baselines/reference/objectTypesIdentityWithNumericIndexers3.types
@@ -50,7 +50,7 @@ var a: {
 var b: { [x: number]: string; } = { foo: '' };
 >b : { [x: number]: string; }
 >x : number
->{ foo: '' } : { [x: number]: undefined; foo: string; }
+>{ foo: '' } : { foo: string; }
 >foo : string
 >'' : string
 
diff --git a/tests/baselines/reference/objectTypesIdentityWithStringIndexers.types b/tests/baselines/reference/objectTypesIdentityWithStringIndexers.types
index a7eeb672504..8393eaf68a0 100644
--- a/tests/baselines/reference/objectTypesIdentityWithStringIndexers.types
+++ b/tests/baselines/reference/objectTypesIdentityWithStringIndexers.types
@@ -50,7 +50,7 @@ var a: {
 var b: { [x: string]: string; } = { foo: '' };
 >b : { [x: string]: string; }
 >x : string
->{ foo: '' } : { [x: string]: string; foo: string; }
+>{ foo: '' } : { foo: string; }
 >foo : string
 >'' : string
 
diff --git a/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.types b/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.types
index d1394252117..814d0c91814 100644
--- a/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.types
+++ b/tests/baselines/reference/objectTypesIdentityWithStringIndexers2.types
@@ -64,7 +64,7 @@ var b: { [x: string]: Derived; } = { foo: <Derived>null };
 >b : { [x: string]: Derived; }
 >x : string
 >Derived : Derived
->{ foo: <Derived>null } : { [x: string]: Derived; foo: Derived; }
+>{ foo: <Derived>null } : { foo: Derived; }
 >foo : Derived
 ><Derived>null : Derived
 >Derived : Derived
diff --git a/tests/baselines/reference/operatorsAndIntersectionTypes.types b/tests/baselines/reference/operatorsAndIntersectionTypes.types
index 70611776fc1..6b5987d3a69 100644
--- a/tests/baselines/reference/operatorsAndIntersectionTypes.types
+++ b/tests/baselines/reference/operatorsAndIntersectionTypes.types
@@ -28,7 +28,7 @@ function createSerialNo() {
 let map1: { [x: string]: number } = {};
 >map1 : { [x: string]: number; }
 >x : string
->{} : { [x: string]: undefined; }
+>{} : {}
 
 let guid = createGuid();
 >guid : string & { $Guid: any; }
@@ -45,7 +45,7 @@ map1[guid] = 123;  // Can with tagged string
 let map2: { [x: number]: string } = {};
 >map2 : { [x: number]: string; }
 >x : number
->{} : { [x: number]: undefined; }
+>{} : {}
 
 let serialNo = createSerialNo();
 >serialNo : number & { $SerialNo: any; }
diff --git a/tests/baselines/reference/parserConstructorDeclaration5.errors.txt b/tests/baselines/reference/parserConstructorDeclaration5.errors.txt
deleted file mode 100644
index 4589ad95a32..00000000000
--- a/tests/baselines/reference/parserConstructorDeclaration5.errors.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration5.ts(2,3): error TS1089: 'private' modifier cannot appear on a constructor declaration.
-
-
-==== tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration5.ts (1 errors) ====
-    class C {
-      private constructor() { }
-      ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserConstructorDeclaration5.symbols b/tests/baselines/reference/parserConstructorDeclaration5.symbols
new file mode 100644
index 00000000000..6eb3d32a0f0
--- /dev/null
+++ b/tests/baselines/reference/parserConstructorDeclaration5.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration5.ts ===
+class C {
+>C : Symbol(C, Decl(parserConstructorDeclaration5.ts, 0, 0))
+
+  private constructor() { }
+}
diff --git a/tests/baselines/reference/parserConstructorDeclaration5.types b/tests/baselines/reference/parserConstructorDeclaration5.types
new file mode 100644
index 00000000000..ae5d2c44b49
--- /dev/null
+++ b/tests/baselines/reference/parserConstructorDeclaration5.types
@@ -0,0 +1,6 @@
+=== tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration5.ts ===
+class C {
+>C : C
+
+  private constructor() { }
+}
diff --git a/tests/baselines/reference/protectedMembers.errors.txt b/tests/baselines/reference/protectedMembers.errors.txt
index c35bc25fe71..666be34d10c 100644
--- a/tests/baselines/reference/protectedMembers.errors.txt
+++ b/tests/baselines/reference/protectedMembers.errors.txt
@@ -8,16 +8,15 @@ tests/cases/compiler/protectedMembers.ts(48,1): error TS2445: Property 'sx' is p
 tests/cases/compiler/protectedMembers.ts(49,1): error TS2445: Property 'sf' is protected and only accessible within class 'C2' and its subclasses.
 tests/cases/compiler/protectedMembers.ts(68,9): error TS2446: Property 'x' is protected and only accessible through an instance of class 'C'.
 tests/cases/compiler/protectedMembers.ts(69,9): error TS2446: Property 'x' is protected and only accessible through an instance of class 'C'.
-tests/cases/compiler/protectedMembers.ts(86,5): error TS1089: 'protected' modifier cannot appear on a constructor declaration.
-tests/cases/compiler/protectedMembers.ts(98,1): error TS2322: Type 'B1' is not assignable to type 'A1'.
+tests/cases/compiler/protectedMembers.ts(97,1): error TS2322: Type 'B1' is not assignable to type 'A1'.
   Property 'x' is protected but type 'B1' is not a class derived from 'A1'.
-tests/cases/compiler/protectedMembers.ts(99,1): error TS2322: Type 'A1' is not assignable to type 'B1'.
+tests/cases/compiler/protectedMembers.ts(98,1): error TS2322: Type 'A1' is not assignable to type 'B1'.
   Property 'x' is protected in type 'A1' but public in type 'B1'.
-tests/cases/compiler/protectedMembers.ts(112,7): error TS2415: Class 'B3' incorrectly extends base class 'A3'.
+tests/cases/compiler/protectedMembers.ts(111,7): error TS2415: Class 'B3' incorrectly extends base class 'A3'.
   Property 'x' is protected in type 'B3' but public in type 'A3'.
 
 
-==== tests/cases/compiler/protectedMembers.ts (14 errors) ====
+==== tests/cases/compiler/protectedMembers.ts (13 errors) ====
     // Class with protected members
     class C1 {
         protected x: number;
@@ -122,10 +121,7 @@ tests/cases/compiler/protectedMembers.ts(112,7): error TS2415: Class 'B3' incorr
     }
     
     class CC {
-        // Error, constructor cannot be protected
         protected constructor() {
-        ~~~~~~~~~
-!!! error TS1089: 'protected' modifier cannot appear on a constructor declaration.
         }
     }
     
diff --git a/tests/baselines/reference/protectedMembers.js b/tests/baselines/reference/protectedMembers.js
index e541f697f44..dcc68e0c946 100644
--- a/tests/baselines/reference/protectedMembers.js
+++ b/tests/baselines/reference/protectedMembers.js
@@ -83,7 +83,6 @@ interface E extends C {
 }
 
 class CC {
-    // Error, constructor cannot be protected
     protected constructor() {
     }
 }
@@ -214,7 +213,6 @@ var D = (function (_super) {
     return D;
 }(C));
 var CC = (function () {
-    // Error, constructor cannot be protected
     function CC() {
     }
     return CC;
diff --git a/tests/baselines/reference/relativeNamesInClassicResolution.errors.txt b/tests/baselines/reference/relativeNamesInClassicResolution.errors.txt
new file mode 100644
index 00000000000..65a42775331
--- /dev/null
+++ b/tests/baselines/reference/relativeNamesInClassicResolution.errors.txt
@@ -0,0 +1,11 @@
+tests/cases/compiler/somefolder/a.ts(2,17): error TS2307: Cannot find module './b'.
+
+
+==== tests/cases/compiler/somefolder/a.ts (1 errors) ====
+    
+    import {x} from "./b"
+                    ~~~~~
+!!! error TS2307: Cannot find module './b'.
+    
+==== tests/cases/compiler/b.ts (0 errors) ====
+    export let x = 1;
\ No newline at end of file
diff --git a/tests/baselines/reference/relativeNamesInClassicResolution.js b/tests/baselines/reference/relativeNamesInClassicResolution.js
new file mode 100644
index 00000000000..a6c5a06ea3d
--- /dev/null
+++ b/tests/baselines/reference/relativeNamesInClassicResolution.js
@@ -0,0 +1,18 @@
+//// [tests/cases/compiler/relativeNamesInClassicResolution.ts] ////
+
+//// [a.ts]
+
+import {x} from "./b"
+
+//// [b.ts]
+export let x = 1;
+
+//// [a.js]
+define(["require", "exports"], function (require, exports) {
+    "use strict";
+});
+//// [b.js]
+define(["require", "exports"], function (require, exports) {
+    "use strict";
+    exports.x = 1;
+});
diff --git a/tests/baselines/reference/restElementWithNullInitializer.errors.txt b/tests/baselines/reference/restElementWithNullInitializer.errors.txt
index 7beb7b9a642..4658acc5ff4 100644
--- a/tests/baselines/reference/restElementWithNullInitializer.errors.txt
+++ b/tests/baselines/reference/restElementWithNullInitializer.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts(1,15): error TS2461: Type 'null' is not an array type.
 tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts(4,15): error TS2461: Type 'undefined' is not an array type.
-tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts(7,15): error TS2461: Type '{ [x: number]: undefined; }' is not an array type.
+tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts(7,15): error TS2461: Type '{}' is not an array type.
 
 
 ==== tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts (3 errors) ====
@@ -16,7 +16,7 @@ tests/cases/conformance/es6/destructuring/restElementWithNullInitializer.ts(7,15
     
     function foo3([...r] = {}) {
                   ~~~~~~
-!!! error TS2461: Type '{ [x: number]: undefined; }' is not an array type.
+!!! error TS2461: Type '{}' is not an array type.
     }
     
     function foo4([...r] = []) {
diff --git a/tests/baselines/reference/stringIndexerAssignments1.errors.txt b/tests/baselines/reference/stringIndexerAssignments1.errors.txt
index 908371bc7dd..ac99b239779 100644
--- a/tests/baselines/reference/stringIndexerAssignments1.errors.txt
+++ b/tests/baselines/reference/stringIndexerAssignments1.errors.txt
@@ -1,18 +1,13 @@
-tests/cases/compiler/stringIndexerAssignments1.ts(4,1): error TS2322: Type '{ one: string; }' is not assignable to type '{ [index: string]: string; one: string; }'.
-  Index signature is missing in type '{ one: string; }'.
 tests/cases/compiler/stringIndexerAssignments1.ts(5,1): error TS2322: Type '{ one: number; two: string; }' is not assignable to type '{ [index: string]: string; one: string; }'.
   Types of property 'one' are incompatible.
     Type 'number' is not assignable to type 'string'.
 
 
-==== tests/cases/compiler/stringIndexerAssignments1.ts (2 errors) ====
+==== tests/cases/compiler/stringIndexerAssignments1.ts (1 errors) ====
     var x: { [index: string]: string; one: string; };
     var a: { one: string; };
     var b: { one: number; two: string; };
     x = a;
-    ~
-!!! error TS2322: Type '{ one: string; }' is not assignable to type '{ [index: string]: string; one: string; }'.
-!!! error TS2322:   Index signature is missing in type '{ one: string; }'.
     x = b; // error
     ~
 !!! error TS2322: Type '{ one: number; two: string; }' is not assignable to type '{ [index: string]: string; one: string; }'.
diff --git a/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations.errors.txt b/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations.errors.txt
index 08881be2a86..8f4bbe2025a 100644
--- a/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations.errors.txt
+++ b/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations.errors.txt
@@ -22,10 +22,9 @@ tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerCon
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations.ts(71,5): error TS2411: Property 'foo' of type '() => string' is not assignable to string index type 'string'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations.ts(73,5): error TS2411: Property '"4.0"' of type 'number' is not assignable to string index type 'string'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations.ts(74,5): error TS2411: Property 'f' of type 'MyString' is not assignable to string index type 'string'.
-tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations.ts(78,5): error TS2322: Type '{ [x: string]: string | number | (() => void) | MyString; 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: MyString; X: string; foo(): string; }' is not assignable to type '{ [x: string]: string; }'.
-  Index signatures are incompatible.
-    Type 'string | number | (() => void) | MyString' is not assignable to type 'string'.
-      Type 'number' is not assignable to type 'string'.
+tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations.ts(78,5): error TS2322: Type '{ 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: MyString; X: string; foo(): string; }' is not assignable to type '{ [x: string]: string; }'.
+  Property '2.0' is incompatible with index signature.
+    Type 'number' is not assignable to type 'string'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations.ts(90,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations.ts(93,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 
@@ -158,10 +157,9 @@ tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerCon
     // error
     var b: { [x: string]: string; } = {
         ~
-!!! error TS2322: Type '{ [x: string]: string | number | (() => void) | MyString; 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: MyString; X: string; foo(): string; }' is not assignable to type '{ [x: string]: string; }'.
-!!! error TS2322:   Index signatures are incompatible.
-!!! error TS2322:     Type 'string | number | (() => void) | MyString' is not assignable to type 'string'.
-!!! error TS2322:       Type 'number' is not assignable to type 'string'.
+!!! error TS2322: Type '{ 1.0: string; 2.0: number; a: string; b: number; c: () => void; "d": string; "e": number; "3.0": string; "4.0": number; f: MyString; X: string; foo(): string; }' is not assignable to type '{ [x: string]: string; }'.
+!!! error TS2322:   Property '2.0' is incompatible with index signature.
+!!! error TS2322:     Type 'number' is not assignable to type 'string'.
         a: '',
         b: 1, 
         c: () => { }, 
diff --git a/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.errors.txt b/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.errors.txt
index faef7905453..dacfb1a522d 100644
--- a/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.errors.txt
+++ b/tests/baselines/reference/stringIndexerConstrainsPropertyDeclarations2.errors.txt
@@ -4,8 +4,8 @@ tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerCon
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations2.ts(24,5): error TS2411: Property 'd' of type 'string' is not assignable to string index type 'A'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations2.ts(31,5): error TS2411: Property 'c' of type 'number' is not assignable to string index type 'A'.
 tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations2.ts(32,5): error TS2411: Property 'd' of type 'string' is not assignable to string index type 'A'.
-tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations2.ts(36,5): error TS2322: Type '{ [x: string]: typeof A; a: typeof A; b: typeof B; }' is not assignable to type '{ [x: string]: A; }'.
-  Index signatures are incompatible.
+tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerConstrainsPropertyDeclarations2.ts(36,5): error TS2322: Type '{ a: typeof A; b: typeof B; }' is not assignable to type '{ [x: string]: A; }'.
+  Property 'a' is incompatible with index signature.
     Type 'typeof A' is not assignable to type 'A'.
       Property 'foo' is missing in type 'typeof A'.
 
@@ -60,8 +60,8 @@ tests/cases/conformance/types/objectTypeLiteral/indexSignatures/stringIndexerCon
     // error
     var b: { [x: string]: A } = {
         ~
-!!! error TS2322: Type '{ [x: string]: typeof A; a: typeof A; b: typeof B; }' is not assignable to type '{ [x: string]: A; }'.
-!!! error TS2322:   Index signatures are incompatible.
+!!! error TS2322: Type '{ a: typeof A; b: typeof B; }' is not assignable to type '{ [x: string]: A; }'.
+!!! error TS2322:   Property 'a' is incompatible with index signature.
 !!! error TS2322:     Type 'typeof A' is not assignable to type 'A'.
 !!! error TS2322:       Property 'foo' is missing in type 'typeof A'.
         a: A,
diff --git a/tests/baselines/reference/stringIndexingResults.types b/tests/baselines/reference/stringIndexingResults.types
index 9f613312e5a..1fdc580b1a2 100644
--- a/tests/baselines/reference/stringIndexingResults.types
+++ b/tests/baselines/reference/stringIndexingResults.types
@@ -95,7 +95,7 @@ var r9 = a[1];
 var b: { [x: string]: string } = { y: '' }
 >b : { [x: string]: string; }
 >x : string
->{ y: '' } : { [x: string]: string; y: string; }
+>{ y: '' } : { y: string; }
 >y : string
 >'' : string
 
diff --git a/tests/baselines/reference/stringLiteralCheckedInIf02.types b/tests/baselines/reference/stringLiteralCheckedInIf02.types
index f91eea03097..79f4c6a223a 100644
--- a/tests/baselines/reference/stringLiteralCheckedInIf02.types
+++ b/tests/baselines/reference/stringLiteralCheckedInIf02.types
@@ -31,7 +31,7 @@ function f(foo: T) {
 >T : ("a" | "b")[] | "a" | "b"
 
     if (isS(foo)) {
->isS(foo) : t is "a" | "b"
+>isS(foo) : boolean
 >isS : (t: ("a" | "b")[] | "a" | "b") => t is "a" | "b"
 >foo : ("a" | "b")[] | "a" | "b"
 
diff --git a/tests/baselines/reference/stringLiteralTypesAsTags01.types b/tests/baselines/reference/stringLiteralTypesAsTags01.types
index 6966ede5482..a7f403e76ec 100644
--- a/tests/baselines/reference/stringLiteralTypesAsTags01.types
+++ b/tests/baselines/reference/stringLiteralTypesAsTags01.types
@@ -88,7 +88,7 @@ let x: A = {
 }
 
 if (hasKind(x, "A")) {
->hasKind(x, "A") : entity is A
+>hasKind(x, "A") : boolean
 >hasKind : { (entity: Entity, kind: "A"): entity is A; (entity: Entity, kind: "B"): entity is B; (entity: Entity, kind: "A" | "B"): entity is Entity; }
 >x : A
 >"A" : "A"
@@ -105,7 +105,7 @@ else {
 
 if (!hasKind(x, "B")) {
 >!hasKind(x, "B") : boolean
->hasKind(x, "B") : entity is B
+>hasKind(x, "B") : boolean
 >hasKind : { (entity: Entity, kind: "A"): entity is A; (entity: Entity, kind: "B"): entity is B; (entity: Entity, kind: "A" | "B"): entity is Entity; }
 >x : A
 >"B" : "B"
diff --git a/tests/baselines/reference/stringLiteralTypesAsTags02.types b/tests/baselines/reference/stringLiteralTypesAsTags02.types
index 0b8ea0faf67..edad220b086 100644
--- a/tests/baselines/reference/stringLiteralTypesAsTags02.types
+++ b/tests/baselines/reference/stringLiteralTypesAsTags02.types
@@ -82,7 +82,7 @@ let x: A = {
 }
 
 if (hasKind(x, "A")) {
->hasKind(x, "A") : entity is A
+>hasKind(x, "A") : boolean
 >hasKind : { (entity: Entity, kind: "A"): entity is A; (entity: Entity, kind: "B"): entity is B; }
 >x : A
 >"A" : "A"
@@ -99,7 +99,7 @@ else {
 
 if (!hasKind(x, "B")) {
 >!hasKind(x, "B") : boolean
->hasKind(x, "B") : entity is B
+>hasKind(x, "B") : boolean
 >hasKind : { (entity: Entity, kind: "A"): entity is A; (entity: Entity, kind: "B"): entity is B; }
 >x : A
 >"B" : "B"
diff --git a/tests/baselines/reference/stringLiteralTypesAsTags03.types b/tests/baselines/reference/stringLiteralTypesAsTags03.types
index a1d83a1c058..25816659388 100644
--- a/tests/baselines/reference/stringLiteralTypesAsTags03.types
+++ b/tests/baselines/reference/stringLiteralTypesAsTags03.types
@@ -85,7 +85,7 @@ let x: A = {
 }
 
 if (hasKind(x, "A")) {
->hasKind(x, "A") : entity is A
+>hasKind(x, "A") : boolean
 >hasKind : { (entity: Entity, kind: "A"): entity is A; (entity: Entity, kind: "B"): entity is B; }
 >x : A
 >"A" : "A"
@@ -102,7 +102,7 @@ else {
 
 if (!hasKind(x, "B")) {
 >!hasKind(x, "B") : boolean
->hasKind(x, "B") : entity is B
+>hasKind(x, "B") : boolean
 >hasKind : { (entity: Entity, kind: "A"): entity is A; (entity: Entity, kind: "B"): entity is B; }
 >x : A
 >"B" : "B"
diff --git a/tests/baselines/reference/stringLiteralTypesTypePredicates01.types b/tests/baselines/reference/stringLiteralTypesTypePredicates01.types
index 43c8271b76b..41da80afd30 100644
--- a/tests/baselines/reference/stringLiteralTypesTypePredicates01.types
+++ b/tests/baselines/reference/stringLiteralTypesTypePredicates01.types
@@ -36,7 +36,7 @@ var x: Kind = "A";
 >"A" : "A"
 
 if (kindIs(x, "A")) {
->kindIs(x, "A") : kind is "A"
+>kindIs(x, "A") : boolean
 >kindIs : { (kind: "A" | "B", is: "A"): kind is "A"; (kind: "A" | "B", is: "B"): kind is "B"; }
 >x : "A" | "B"
 >"A" : "A"
@@ -53,7 +53,7 @@ else {
 
 if (!kindIs(x, "B")) {
 >!kindIs(x, "B") : boolean
->kindIs(x, "B") : kind is "B"
+>kindIs(x, "B") : boolean
 >kindIs : { (kind: "A" | "B", is: "A"): kind is "A"; (kind: "A" | "B", is: "B"): kind is "B"; }
 >x : "A" | "B"
 >"B" : "B"
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing1.js b/tests/baselines/reference/superCallBeforeThisAccessing1.js
new file mode 100644
index 00000000000..1fc7ab39c91
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing1.js
@@ -0,0 +1,40 @@
+//// [superCallBeforeThisAccessing1.ts]
+declare var Factory: any
+
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        super(i);
+        var s = {
+            t: this._t
+        }
+        var i = Factory.create(s);
+    }
+}
+
+
+//// [superCallBeforeThisAccessing1.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Base = (function () {
+    function Base(c) {
+    }
+    return Base;
+}());
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        _super.call(this, i);
+        var s = {
+            t: this._t
+        };
+        var i = Factory.create(s);
+    }
+    return D;
+}(Base));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing1.symbols b/tests/baselines/reference/superCallBeforeThisAccessing1.symbols
new file mode 100644
index 00000000000..5a153728a73
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing1.symbols
@@ -0,0 +1,38 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing1.ts ===
+declare var Factory: any
+>Factory : Symbol(Factory, Decl(superCallBeforeThisAccessing1.ts, 0, 11))
+
+class Base {
+>Base : Symbol(Base, Decl(superCallBeforeThisAccessing1.ts, 0, 24))
+
+    constructor(c) { }
+>c : Symbol(c, Decl(superCallBeforeThisAccessing1.ts, 3, 16))
+}
+class D extends Base {
+>D : Symbol(D, Decl(superCallBeforeThisAccessing1.ts, 4, 1))
+>Base : Symbol(Base, Decl(superCallBeforeThisAccessing1.ts, 0, 24))
+
+    private _t;
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing1.ts, 5, 22))
+
+    constructor() {
+        super(i);
+>super : Symbol(Base, Decl(superCallBeforeThisAccessing1.ts, 0, 24))
+>i : Symbol(i, Decl(superCallBeforeThisAccessing1.ts, 12, 11))
+
+        var s = {
+>s : Symbol(s, Decl(superCallBeforeThisAccessing1.ts, 9, 11))
+
+            t: this._t
+>t : Symbol(t, Decl(superCallBeforeThisAccessing1.ts, 9, 17))
+>this._t : Symbol(_t, Decl(superCallBeforeThisAccessing1.ts, 5, 22))
+>this : Symbol(D, Decl(superCallBeforeThisAccessing1.ts, 4, 1))
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing1.ts, 5, 22))
+        }
+        var i = Factory.create(s);
+>i : Symbol(i, Decl(superCallBeforeThisAccessing1.ts, 12, 11))
+>Factory : Symbol(Factory, Decl(superCallBeforeThisAccessing1.ts, 0, 11))
+>s : Symbol(s, Decl(superCallBeforeThisAccessing1.ts, 9, 11))
+    }
+}
+
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing1.types b/tests/baselines/reference/superCallBeforeThisAccessing1.types
new file mode 100644
index 00000000000..e947653584a
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing1.types
@@ -0,0 +1,43 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing1.ts ===
+declare var Factory: any
+>Factory : any
+
+class Base {
+>Base : Base
+
+    constructor(c) { }
+>c : any
+}
+class D extends Base {
+>D : D
+>Base : Base
+
+    private _t;
+>_t : any
+
+    constructor() {
+        super(i);
+>super(i) : void
+>super : typeof Base
+>i : any
+
+        var s = {
+>s : { t: any; }
+>{            t: this._t        } : { t: any; }
+
+            t: this._t
+>t : any
+>this._t : any
+>this : this
+>_t : any
+        }
+        var i = Factory.create(s);
+>i : any
+>Factory.create(s) : any
+>Factory.create : any
+>Factory : any
+>create : any
+>s : { t: any; }
+    }
+}
+
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing2.js b/tests/baselines/reference/superCallBeforeThisAccessing2.js
new file mode 100644
index 00000000000..e5acf06bbfd
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing2.js
@@ -0,0 +1,31 @@
+//// [superCallBeforeThisAccessing2.ts]
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        super(() => { this._t }); // no error. only check when this is directly accessing in constructor
+    }
+}
+
+
+//// [superCallBeforeThisAccessing2.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Base = (function () {
+    function Base(c) {
+    }
+    return Base;
+}());
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        var _this = this;
+        _super.call(this, function () { _this._t; }); // no error. only check when this is directly accessing in constructor
+    }
+    return D;
+}(Base));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing2.symbols b/tests/baselines/reference/superCallBeforeThisAccessing2.symbols
new file mode 100644
index 00000000000..2df2e62354a
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing2.symbols
@@ -0,0 +1,23 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing2.ts ===
+class Base {
+>Base : Symbol(Base, Decl(superCallBeforeThisAccessing2.ts, 0, 0))
+
+    constructor(c) { }
+>c : Symbol(c, Decl(superCallBeforeThisAccessing2.ts, 1, 16))
+}
+class D extends Base {
+>D : Symbol(D, Decl(superCallBeforeThisAccessing2.ts, 2, 1))
+>Base : Symbol(Base, Decl(superCallBeforeThisAccessing2.ts, 0, 0))
+
+    private _t;
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing2.ts, 3, 22))
+
+    constructor() {
+        super(() => { this._t }); // no error. only check when this is directly accessing in constructor
+>super : Symbol(Base, Decl(superCallBeforeThisAccessing2.ts, 0, 0))
+>this._t : Symbol(_t, Decl(superCallBeforeThisAccessing2.ts, 3, 22))
+>this : Symbol(D, Decl(superCallBeforeThisAccessing2.ts, 2, 1))
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing2.ts, 3, 22))
+    }
+}
+
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing2.types b/tests/baselines/reference/superCallBeforeThisAccessing2.types
new file mode 100644
index 00000000000..cf0f54b6246
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing2.types
@@ -0,0 +1,25 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing2.ts ===
+class Base {
+>Base : Base
+
+    constructor(c) { }
+>c : any
+}
+class D extends Base {
+>D : D
+>Base : Base
+
+    private _t;
+>_t : any
+
+    constructor() {
+        super(() => { this._t }); // no error. only check when this is directly accessing in constructor
+>super(() => { this._t }) : void
+>super : typeof Base
+>() => { this._t } : () => void
+>this._t : any
+>this : this
+>_t : any
+    }
+}
+
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing3.errors.txt b/tests/baselines/reference/superCallBeforeThisAccessing3.errors.txt
new file mode 100644
index 00000000000..90b9b034263
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing3.errors.txt
@@ -0,0 +1,19 @@
+tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing3.ts(9,9): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
+
+
+==== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing3.ts (1 errors) ====
+    class Base {
+        constructor(c) { }
+    }
+    class D extends Base {
+        private _t;
+        constructor() {
+            let x = () => { this._t };
+            x();  // no error; we only check super is called before this when the container is a constructor
+            this._t;  // error
+            ~~~~
+!!! error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
+            super(undefined);
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing3.js b/tests/baselines/reference/superCallBeforeThisAccessing3.js
new file mode 100644
index 00000000000..101d74e4bc7
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing3.js
@@ -0,0 +1,37 @@
+//// [superCallBeforeThisAccessing3.ts]
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        let x = () => { this._t };
+        x();  // no error; we only check super is called before this when the container is a constructor
+        this._t;  // error
+        super(undefined);
+    }
+}
+
+
+//// [superCallBeforeThisAccessing3.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Base = (function () {
+    function Base(c) {
+    }
+    return Base;
+}());
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        var _this = this;
+        var x = function () { _this._t; };
+        x(); // no error; we only check super is called before this when the container is a constructor
+        this._t; // error
+        _super.call(this, undefined);
+    }
+    return D;
+}(Base));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing4.errors.txt b/tests/baselines/reference/superCallBeforeThisAccessing4.errors.txt
new file mode 100644
index 00000000000..91c3e7763f6
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing4.errors.txt
@@ -0,0 +1,24 @@
+tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing4.ts(5,9): error TS17005: A constructor cannot contain a 'super' call when its class extends 'null'
+tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing4.ts(12,9): error TS17005: A constructor cannot contain a 'super' call when its class extends 'null'
+
+
+==== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing4.ts (2 errors) ====
+    class D extends null {
+        private _t;
+        constructor() {
+            this._t;
+            super();
+            ~~~~~~~
+!!! error TS17005: A constructor cannot contain a 'super' call when its class extends 'null'
+        }
+    }
+    
+    class E extends null {
+        private _t;
+        constructor() {
+            super();
+            ~~~~~~~
+!!! error TS17005: A constructor cannot contain a 'super' call when its class extends 'null'
+            this._t;
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing4.js b/tests/baselines/reference/superCallBeforeThisAccessing4.js
new file mode 100644
index 00000000000..9c3c5ab60c4
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing4.js
@@ -0,0 +1,39 @@
+//// [superCallBeforeThisAccessing4.ts]
+class D extends null {
+    private _t;
+    constructor() {
+        this._t;
+        super();
+    }
+}
+
+class E extends null {
+    private _t;
+    constructor() {
+        super();
+        this._t;
+    }
+}
+
+//// [superCallBeforeThisAccessing4.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        this._t;
+        _super.call(this);
+    }
+    return D;
+}(null));
+var E = (function (_super) {
+    __extends(E, _super);
+    function E() {
+        _super.call(this);
+        this._t;
+    }
+    return E;
+}(null));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing5.js b/tests/baselines/reference/superCallBeforeThisAccessing5.js
new file mode 100644
index 00000000000..3281a3f8b55
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing5.js
@@ -0,0 +1,22 @@
+//// [superCallBeforeThisAccessing5.ts]
+class D extends null {
+    private _t;
+    constructor() {
+        this._t;  // No error
+    }
+}
+
+
+//// [superCallBeforeThisAccessing5.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        this._t; // No error
+    }
+    return D;
+}(null));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing5.symbols b/tests/baselines/reference/superCallBeforeThisAccessing5.symbols
new file mode 100644
index 00000000000..a7628e3b8df
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing5.symbols
@@ -0,0 +1,15 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing5.ts ===
+class D extends null {
+>D : Symbol(D, Decl(superCallBeforeThisAccessing5.ts, 0, 0))
+
+    private _t;
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing5.ts, 0, 22))
+
+    constructor() {
+        this._t;  // No error
+>this._t : Symbol(_t, Decl(superCallBeforeThisAccessing5.ts, 0, 22))
+>this : Symbol(D, Decl(superCallBeforeThisAccessing5.ts, 0, 0))
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing5.ts, 0, 22))
+    }
+}
+
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing5.types b/tests/baselines/reference/superCallBeforeThisAccessing5.types
new file mode 100644
index 00000000000..2c0fc33c4dc
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing5.types
@@ -0,0 +1,16 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing5.ts ===
+class D extends null {
+>D : D
+>null : null
+
+    private _t;
+>_t : any
+
+    constructor() {
+        this._t;  // No error
+>this._t : any
+>this : this
+>_t : any
+    }
+}
+
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing6.errors.txt b/tests/baselines/reference/superCallBeforeThisAccessing6.errors.txt
new file mode 100644
index 00000000000..346b2d58bec
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing6.errors.txt
@@ -0,0 +1,16 @@
+tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing6.ts(7,15): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
+
+
+==== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing6.ts (1 errors) ====
+    class Base {
+        constructor(c) { }
+    }
+    class D extends Base {
+        private _t;
+        constructor() {
+            super(this); 
+                  ~~~~
+!!! error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing6.js b/tests/baselines/reference/superCallBeforeThisAccessing6.js
new file mode 100644
index 00000000000..746ce9f2791
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing6.js
@@ -0,0 +1,30 @@
+//// [superCallBeforeThisAccessing6.ts]
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        super(this); 
+    }
+}
+
+
+//// [superCallBeforeThisAccessing6.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Base = (function () {
+    function Base(c) {
+    }
+    return Base;
+}());
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        _super.call(this, this);
+    }
+    return D;
+}(Base));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing7.errors.txt b/tests/baselines/reference/superCallBeforeThisAccessing7.errors.txt
new file mode 100644
index 00000000000..4e374fd96ea
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing7.errors.txt
@@ -0,0 +1,19 @@
+tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing7.ts(8,16): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
+
+
+==== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing7.ts (1 errors) ====
+    class Base {
+        constructor(c) { }
+    }
+    class D extends Base {
+        private _t;
+        constructor() {
+            let x = {
+                j: this._t,
+                   ~~~~
+!!! error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
+            }
+            super(undefined);
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing7.js b/tests/baselines/reference/superCallBeforeThisAccessing7.js
new file mode 100644
index 00000000000..c3aa1655cf7
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing7.js
@@ -0,0 +1,36 @@
+//// [superCallBeforeThisAccessing7.ts]
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        let x = {
+            j: this._t,
+        }
+        super(undefined);
+    }
+}
+
+
+//// [superCallBeforeThisAccessing7.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Base = (function () {
+    function Base(c) {
+    }
+    return Base;
+}());
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        var x = {
+            j: this._t
+        };
+        _super.call(this, undefined);
+    }
+    return D;
+}(Base));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing8.js b/tests/baselines/reference/superCallBeforeThisAccessing8.js
new file mode 100644
index 00000000000..0865c4305a5
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing8.js
@@ -0,0 +1,36 @@
+//// [superCallBeforeThisAccessing8.ts]
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        let x = {
+            k: super(undefined), 
+            j: this._t,  // no error
+        }
+    }
+}
+
+
+//// [superCallBeforeThisAccessing8.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Base = (function () {
+    function Base(c) {
+    }
+    return Base;
+}());
+var D = (function (_super) {
+    __extends(D, _super);
+    function D() {
+        var x = {
+            k: _super.call(this, undefined),
+            j: this._t
+        };
+    }
+    return D;
+}(Base));
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing8.symbols b/tests/baselines/reference/superCallBeforeThisAccessing8.symbols
new file mode 100644
index 00000000000..65341ee9fe3
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing8.symbols
@@ -0,0 +1,32 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing8.ts ===
+class Base {
+>Base : Symbol(Base, Decl(superCallBeforeThisAccessing8.ts, 0, 0))
+
+    constructor(c) { }
+>c : Symbol(c, Decl(superCallBeforeThisAccessing8.ts, 1, 16))
+}
+class D extends Base {
+>D : Symbol(D, Decl(superCallBeforeThisAccessing8.ts, 2, 1))
+>Base : Symbol(Base, Decl(superCallBeforeThisAccessing8.ts, 0, 0))
+
+    private _t;
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing8.ts, 3, 22))
+
+    constructor() {
+        let x = {
+>x : Symbol(x, Decl(superCallBeforeThisAccessing8.ts, 6, 11))
+
+            k: super(undefined), 
+>k : Symbol(k, Decl(superCallBeforeThisAccessing8.ts, 6, 17))
+>super : Symbol(Base, Decl(superCallBeforeThisAccessing8.ts, 0, 0))
+>undefined : Symbol(undefined)
+
+            j: this._t,  // no error
+>j : Symbol(j, Decl(superCallBeforeThisAccessing8.ts, 7, 32))
+>this._t : Symbol(_t, Decl(superCallBeforeThisAccessing8.ts, 3, 22))
+>this : Symbol(D, Decl(superCallBeforeThisAccessing8.ts, 2, 1))
+>_t : Symbol(_t, Decl(superCallBeforeThisAccessing8.ts, 3, 22))
+        }
+    }
+}
+
diff --git a/tests/baselines/reference/superCallBeforeThisAccessing8.types b/tests/baselines/reference/superCallBeforeThisAccessing8.types
new file mode 100644
index 00000000000..dd92d924ceb
--- /dev/null
+++ b/tests/baselines/reference/superCallBeforeThisAccessing8.types
@@ -0,0 +1,34 @@
+=== tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing8.ts ===
+class Base {
+>Base : Base
+
+    constructor(c) { }
+>c : any
+}
+class D extends Base {
+>D : D
+>Base : Base
+
+    private _t;
+>_t : any
+
+    constructor() {
+        let x = {
+>x : { k: void; j: any; }
+>{            k: super(undefined),             j: this._t,  // no error        } : { k: void; j: any; }
+
+            k: super(undefined), 
+>k : void
+>super(undefined) : void
+>super : typeof Base
+>undefined : undefined
+
+            j: this._t,  // no error
+>j : any
+>this._t : any
+>this : this
+>_t : any
+        }
+    }
+}
+
diff --git a/tests/baselines/reference/symbolProperty1.types b/tests/baselines/reference/symbolProperty1.types
index f39d98853d2..667e51fda8a 100644
--- a/tests/baselines/reference/symbolProperty1.types
+++ b/tests/baselines/reference/symbolProperty1.types
@@ -3,8 +3,8 @@ var s: symbol;
 >s : symbol
 
 var x = {
->x : {}
->{    [s]: 0,    [s]() { },    get [s]() {        return 0;    }} : {}
+>x : { [x: string]: number | (() => void); }
+>{    [s]: 0,    [s]() { },    get [s]() {        return 0;    }} : { [x: string]: number | (() => void); }
 
     [s]: 0,
 >s : symbol
diff --git a/tests/baselines/reference/symbolProperty2.types b/tests/baselines/reference/symbolProperty2.types
index df49130520a..7584c6461e8 100644
--- a/tests/baselines/reference/symbolProperty2.types
+++ b/tests/baselines/reference/symbolProperty2.types
@@ -5,8 +5,8 @@ var s = Symbol();
 >Symbol : SymbolConstructor
 
 var x = {
->x : {}
->{    [s]: 0,    [s]() { },    get [s]() {        return 0;    }} : {}
+>x : { [x: string]: number | (() => void); }
+>{    [s]: 0,    [s]() { },    get [s]() {        return 0;    }} : { [x: string]: number | (() => void); }
 
     [s]: 0,
 >s : symbol
diff --git a/tests/baselines/reference/symbolProperty4.types b/tests/baselines/reference/symbolProperty4.types
index 93b4417b8ae..7bcf3f23397 100644
--- a/tests/baselines/reference/symbolProperty4.types
+++ b/tests/baselines/reference/symbolProperty4.types
@@ -1,7 +1,7 @@
 === tests/cases/conformance/es6/Symbols/symbolProperty4.ts ===
 var x = {
->x : {}
->{    [Symbol()]: 0,    [Symbol()]() { },    get [Symbol()]() {        return 0;    }} : {}
+>x : { [x: string]: number | (() => void); }
+>{    [Symbol()]: 0,    [Symbol()]() { },    get [Symbol()]() {        return 0;    }} : { [x: string]: number | (() => void); }
 
     [Symbol()]: 0,
 >Symbol() : symbol
diff --git a/tests/baselines/reference/templateStringsArrayTypeDefinedInES5Mode.errors.txt b/tests/baselines/reference/templateStringsArrayTypeDefinedInES5Mode.errors.txt
index e6910840d39..94ab5028647 100644
--- a/tests/baselines/reference/templateStringsArrayTypeDefinedInES5Mode.errors.txt
+++ b/tests/baselines/reference/templateStringsArrayTypeDefinedInES5Mode.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts(8,3): error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'TemplateStringsArray'.
-  Property 'raw' is missing in type '{ [x: number]: undefined; }'.
+tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts(8,3): error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
+  Property 'raw' is missing in type '{}'.
 
 
 ==== tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts (1 errors) ====
@@ -12,7 +12,7 @@ tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts(8,3): error TS2
     
     f({}, 10, 10);
       ~~
-!!! error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'TemplateStringsArray'.
-!!! error TS2345:   Property 'raw' is missing in type '{ [x: number]: undefined; }'.
+!!! error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
+!!! error TS2345:   Property 'raw' is missing in type '{}'.
     
     f `abcdef${ 1234 }${ 5678 }ghijkl`;
\ No newline at end of file
diff --git a/tests/baselines/reference/templateStringsArrayTypeNotDefinedES5Mode.errors.txt b/tests/baselines/reference/templateStringsArrayTypeNotDefinedES5Mode.errors.txt
index e8bf38c1048..1201c82f4d0 100644
--- a/tests/baselines/reference/templateStringsArrayTypeNotDefinedES5Mode.errors.txt
+++ b/tests/baselines/reference/templateStringsArrayTypeNotDefinedES5Mode.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/templateStringsArrayTypeNotDefinedES5Mode.ts(5,3): error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'TemplateStringsArray'.
-  Property 'raw' is missing in type '{ [x: number]: undefined; }'.
+tests/cases/compiler/templateStringsArrayTypeNotDefinedES5Mode.ts(5,3): error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
+  Property 'raw' is missing in type '{}'.
 
 
 ==== tests/cases/compiler/templateStringsArrayTypeNotDefinedES5Mode.ts (1 errors) ====
@@ -9,7 +9,7 @@ tests/cases/compiler/templateStringsArrayTypeNotDefinedES5Mode.ts(5,3): error TS
     
     f({}, 10, 10);
       ~~
-!!! error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'TemplateStringsArray'.
-!!! error TS2345:   Property 'raw' is missing in type '{ [x: number]: undefined; }'.
+!!! error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
+!!! error TS2345:   Property 'raw' is missing in type '{}'.
     
     f `abcdef${ 1234 }${ 5678 }ghijkl`;
\ No newline at end of file
diff --git a/tests/baselines/reference/templateStringsArrayTypeRedefinedInES6Mode.errors.txt b/tests/baselines/reference/templateStringsArrayTypeRedefinedInES6Mode.errors.txt
index ac30556a235..f410d408482 100644
--- a/tests/baselines/reference/templateStringsArrayTypeRedefinedInES6Mode.errors.txt
+++ b/tests/baselines/reference/templateStringsArrayTypeRedefinedInES6Mode.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts(8,3): error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'TemplateStringsArray'.
-  Property 'raw' is missing in type '{ [x: number]: undefined; }'.
+tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts(8,3): error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
+  Property 'raw' is missing in type '{}'.
 
 
 ==== tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts (1 errors) ====
@@ -12,7 +12,7 @@ tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts(8,3): error T
     
     f({}, 10, 10);
       ~~
-!!! error TS2345: Argument of type '{ [x: number]: undefined; }' is not assignable to parameter of type 'TemplateStringsArray'.
-!!! error TS2345:   Property 'raw' is missing in type '{ [x: number]: undefined; }'.
+!!! error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
+!!! error TS2345:   Property 'raw' is missing in type '{}'.
     
     f `abcdef${ 1234 }${ 5678 }ghijkl`;
\ No newline at end of file
diff --git a/tests/baselines/reference/typeGuardFunction.types b/tests/baselines/reference/typeGuardFunction.types
index 9bab1e7ca2c..50a5fcaf324 100644
--- a/tests/baselines/reference/typeGuardFunction.types
+++ b/tests/baselines/reference/typeGuardFunction.types
@@ -54,7 +54,7 @@ var b: B;
 
 // Basic
 if (isC(a)) {
->isC(a) : p1 is C
+>isC(a) : boolean
 >isC : (p1: any) => p1 is C
 >a : A
 
@@ -70,7 +70,7 @@ var subType: C;
 >C : C
 
 if(isA(subType)) {
->isA(subType) : p1 is A
+>isA(subType) : boolean
 >isA : (p1: any) => p1 is A
 >subType : C
 
@@ -87,7 +87,7 @@ var union: A | B;
 >B : B
 
 if(isA(union)) {
->isA(union) : p1 is A
+>isA(union) : boolean
 >isA : (p1: any) => p1 is A
 >union : A | B
 
@@ -118,7 +118,7 @@ declare function isC_multipleParams(p1, p2): p1 is C;
 >C : C
 
 if (isC_multipleParams(a, 0)) {
->isC_multipleParams(a, 0) : p1 is C
+>isC_multipleParams(a, 0) : boolean
 >isC_multipleParams : (p1: any, p2: any) => p1 is C
 >a : A
 >0 : number
@@ -197,7 +197,7 @@ declare function acceptingBoolean(a: boolean);
 acceptingBoolean(isA(a));
 >acceptingBoolean(isA(a)) : any
 >acceptingBoolean : (a: boolean) => any
->isA(a) : p1 is A
+>isA(a) : boolean
 >isA : (p1: any) => p1 is A
 >a : A
 
@@ -223,8 +223,8 @@ let union2: C | B;
 let union3: boolean | B = isA(union2) || union2;
 >union3 : boolean | B
 >B : B
->isA(union2) || union2 : p1 is A | B
->isA(union2) : p1 is A
+>isA(union2) || union2 : boolean | B
+>isA(union2) : boolean
 >isA : (p1: any) => p1 is A
 >union2 : C | B
 >union2 : B
diff --git a/tests/baselines/reference/typeGuardFunctionErrors.errors.txt b/tests/baselines/reference/typeGuardFunctionErrors.errors.txt
index 9ecad007672..8e4bf651518 100644
--- a/tests/baselines/reference/typeGuardFunctionErrors.errors.txt
+++ b/tests/baselines/reference/typeGuardFunctionErrors.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(2,7): error TS2300: Duplicate identifier 'A'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(15,12): error TS2322: Type 'string' is not assignable to type 'x is A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(15,12): error TS2322: Type 'string' is not assignable to type 'boolean'.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(18,55): error TS2304: Cannot find name 'x'.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(18,57): error TS1144: '{' or ';' expected.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(18,57): error TS2304: Cannot find name 'is'.
@@ -43,9 +43,13 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,22)
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,22): error TS2304: Cannot find name 'is'.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,25): error TS1005: ';' expected.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,27): error TS1005: ';' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(104,25): error TS1228: A type predicate is only allowed in return type position for functions and methods.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(105,16): error TS2322: Type 'boolean' is not assignable to type 'D'.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(105,16): error TS2409: Return type of constructor signature must be assignable to the instance type of the class
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(107,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(110,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(111,16): error TS2408: Setters cannot return a value.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(116,18): error TS1228: A type predicate is only allowed in return type position for functions and methods.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(120,22): error TS2304: Cannot find name 'p1'.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(120,25): error TS1005: ';' expected.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(120,25): error TS2304: Cannot find name 'is'.
@@ -57,7 +61,7 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(133,34
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
 
 
-==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (50 errors) ====
+==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (54 errors) ====
     
     class A {
           ~
@@ -76,7 +80,7 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39
     function hasANonBooleanReturnStatement(x): x is A {
         return '';
                ~~
-!!! error TS2322: Type 'string' is not assignable to type 'x is A'.
+!!! error TS2322: Type 'string' is not assignable to type 'boolean'.
     }
     
     function hasTypeGuardTypeInsideTypeGuardType(x): x is x is A {
@@ -245,6 +249,8 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39
     // Non-compatiable type predicate positions for signature declarations
     class D {
         constructor(p1: A): p1 is C {
+                            ~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
             return true;
                    ~~~~
 !!! error TS2322: Type 'boolean' is not assignable to type 'D'.
@@ -252,9 +258,13 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39
 !!! error TS2409: Return type of constructor signature must be assignable to the instance type of the class
         }
         get m1(p1: A): p1 is C {
+                       ~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
             return true;
         }
         set m2(p1: A): p1 is C {
+                       ~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
             return true;
                    ~~~~
 !!! error TS2408: Setters cannot return a value.
@@ -263,6 +273,8 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39
     
     interface I1 {
         new (p1: A): p1 is C;
+                     ~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
     }
     
     interface I2 {
diff --git a/tests/baselines/reference/typeGuardFunctionGenerics.types b/tests/baselines/reference/typeGuardFunctionGenerics.types
index 1f2ad2b69be..c4655e71f0c 100644
--- a/tests/baselines/reference/typeGuardFunctionGenerics.types
+++ b/tests/baselines/reference/typeGuardFunctionGenerics.types
@@ -100,7 +100,7 @@ let test1: boolean = funA(isB);
 >isB : (p1: any) => p1 is B
 
 if (funB(retC, a)) {
->funB(retC, a) : p2 is C
+>funB(retC, a) : boolean
 >funB : <T>(p1: (p1: any) => T, p2: any) => p2 is T
 >retC : (x: any) => C
 >a : A
@@ -118,7 +118,7 @@ let test2: B = funC(isB);
 >isB : (p1: any) => p1 is B
 
 if (funD(isC, a)) {
->funD(isC, a) : p2 is C
+>funD(isC, a) : boolean
 >funD : <T>(p1: (p1: any) => p1 is T, p2: any) => p2 is T
 >isC : (p1: any) => p1 is C
 >a : A
diff --git a/tests/baselines/reference/typeGuardFunctionOfFormThis.types b/tests/baselines/reference/typeGuardFunctionOfFormThis.types
index e91c77dd07a..6b21fea3457 100644
--- a/tests/baselines/reference/typeGuardFunctionOfFormThis.types
+++ b/tests/baselines/reference/typeGuardFunctionOfFormThis.types
@@ -45,7 +45,7 @@ let a: RoyalGuard = new FollowerGuard();
 >FollowerGuard : typeof FollowerGuard
 
 if (a.isLeader()) {
->a.isLeader() : this is LeadGuard
+>a.isLeader() : boolean
 >a.isLeader : () => this is LeadGuard
 >a : RoyalGuard
 >isLeader : () => this is LeadGuard
@@ -57,7 +57,7 @@ if (a.isLeader()) {
 >lead : () => void
 }
 else if (a.isFollower()) {
->a.isFollower() : this is FollowerGuard
+>a.isFollower() : boolean
 >a.isFollower : () => this is FollowerGuard
 >a : RoyalGuard
 >isFollower : () => this is FollowerGuard
@@ -78,7 +78,7 @@ let b: GuardInterface;
 >GuardInterface : GuardInterface
 
 if (b.isLeader()) {
->b.isLeader() : this is LeadGuard
+>b.isLeader() : boolean
 >b.isLeader : () => this is LeadGuard
 >b : GuardInterface
 >isLeader : () => this is LeadGuard
@@ -90,7 +90,7 @@ if (b.isLeader()) {
 >lead : () => void
 }
 else if (b.isFollower()) {
->b.isFollower() : this is FollowerGuard
+>b.isFollower() : boolean
 >b.isFollower : () => this is FollowerGuard
 >b : GuardInterface
 >isFollower : () => this is FollowerGuard
@@ -103,8 +103,8 @@ else if (b.isFollower()) {
 }
 
 if (((a.isLeader)())) {
->((a.isLeader)()) : this is LeadGuard
->(a.isLeader)() : this is LeadGuard
+>((a.isLeader)()) : boolean
+>(a.isLeader)() : boolean
 >(a.isLeader) : () => this is LeadGuard
 >a.isLeader : () => this is LeadGuard
 >a : RoyalGuard
@@ -117,8 +117,8 @@ if (((a.isLeader)())) {
 >lead : () => void
 }
 else if (((a).isFollower())) {
->((a).isFollower()) : this is FollowerGuard
->(a).isFollower() : this is FollowerGuard
+>((a).isFollower()) : boolean
+>(a).isFollower() : boolean
 >(a).isFollower : () => this is FollowerGuard
 >(a) : RoyalGuard
 >a : RoyalGuard
@@ -132,8 +132,8 @@ else if (((a).isFollower())) {
 }
 
 if (((a["isLeader"])())) {
->((a["isLeader"])()) : this is LeadGuard
->(a["isLeader"])() : this is LeadGuard
+>((a["isLeader"])()) : boolean
+>(a["isLeader"])() : boolean
 >(a["isLeader"]) : () => this is LeadGuard
 >a["isLeader"] : () => this is LeadGuard
 >a : RoyalGuard
@@ -146,8 +146,8 @@ if (((a["isLeader"])())) {
 >lead : () => void
 }
 else if (((a)["isFollower"]())) {
->((a)["isFollower"]()) : this is FollowerGuard
->(a)["isFollower"]() : this is FollowerGuard
+>((a)["isFollower"]()) : boolean
+>(a)["isFollower"]() : boolean
 >(a)["isFollower"] : () => this is FollowerGuard
 >(a) : RoyalGuard
 >a : RoyalGuard
@@ -166,7 +166,7 @@ var holder2 = {a};
 >a : RoyalGuard
 
 if (holder2.a.isLeader()) {
->holder2.a.isLeader() : this is LeadGuard
+>holder2.a.isLeader() : boolean
 >holder2.a.isLeader : () => this is LeadGuard
 >holder2.a : RoyalGuard
 >holder2 : { a: RoyalGuard; }
@@ -232,7 +232,7 @@ let guard = new ArrowGuard();
 >ArrowGuard : typeof ArrowGuard
 
 if (guard.isElite()) {
->guard.isElite() : this is ArrowElite
+>guard.isElite() : boolean
 >guard.isElite : () => this is ArrowElite
 >guard : ArrowGuard
 >isElite : () => this is ArrowElite
@@ -244,7 +244,7 @@ if (guard.isElite()) {
 >defend : () => void
 }
 else if (guard.isMedic()) {
->guard.isMedic() : this is ArrowMedic
+>guard.isMedic() : boolean
 >guard.isMedic : () => this is ArrowMedic
 >guard : ArrowGuard
 >isMedic : () => this is ArrowMedic
@@ -297,7 +297,7 @@ let crate: Crate<{}>;
 >Crate : Crate<T>
 
 if (crate.isSundries()) {
->crate.isSundries() : this is Crate<Sundries>
+>crate.isSundries() : boolean
 >crate.isSundries : () => this is Crate<Sundries>
 >crate : Crate<{}>
 >isSundries : () => this is Crate<Sundries>
@@ -312,7 +312,7 @@ if (crate.isSundries()) {
 >true : boolean
 }
 else if (crate.isSupplies()) {
->crate.isSupplies() : this is Crate<Supplies>
+>crate.isSupplies() : boolean
 >crate.isSupplies : () => this is Crate<Supplies>
 >crate : Crate<{}>
 >isSupplies : () => this is Crate<Supplies>
@@ -405,7 +405,7 @@ a.isFollower = mimic.isFollower;
 >isFollower : () => this is MimicFollower
 
 if (mimic.isFollower()) {
->mimic.isFollower() : this is MimicFollower
+>mimic.isFollower() : boolean
 >mimic.isFollower : () => this is MimicFollower
 >mimic : MimicGuard
 >isFollower : () => this is MimicFollower
diff --git a/tests/baselines/reference/typeGuardOfFormFunctionEquality.js b/tests/baselines/reference/typeGuardOfFormFunctionEquality.js
new file mode 100644
index 00000000000..c15c1a739a9
--- /dev/null
+++ b/tests/baselines/reference/typeGuardOfFormFunctionEquality.js
@@ -0,0 +1,26 @@
+//// [typeGuardOfFormFunctionEquality.ts]
+declare function isString1(a: number, b: Object): b is string;
+
+declare function isString2(a: Object): a is string;
+
+switch (isString1(0, "")) {
+    case isString2(""):
+    default:
+}
+
+var x = isString1(0, "") === isString2("");
+
+function isString3(a: number, b: number, c: Object): c is string {
+    return isString1(0, c);
+}
+
+
+//// [typeGuardOfFormFunctionEquality.js]
+switch (isString1(0, "")) {
+    case isString2(""):
+    default:
+}
+var x = isString1(0, "") === isString2("");
+function isString3(a, b, c) {
+    return isString1(0, c);
+}
diff --git a/tests/baselines/reference/typeGuardOfFormFunctionEquality.symbols b/tests/baselines/reference/typeGuardOfFormFunctionEquality.symbols
new file mode 100644
index 00000000000..f1384050176
--- /dev/null
+++ b/tests/baselines/reference/typeGuardOfFormFunctionEquality.symbols
@@ -0,0 +1,41 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardOfFormFunctionEquality.ts ===
+declare function isString1(a: number, b: Object): b is string;
+>isString1 : Symbol(isString1, Decl(typeGuardOfFormFunctionEquality.ts, 0, 0))
+>a : Symbol(a, Decl(typeGuardOfFormFunctionEquality.ts, 0, 27))
+>b : Symbol(b, Decl(typeGuardOfFormFunctionEquality.ts, 0, 37))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>b : Symbol(b, Decl(typeGuardOfFormFunctionEquality.ts, 0, 37))
+
+declare function isString2(a: Object): a is string;
+>isString2 : Symbol(isString2, Decl(typeGuardOfFormFunctionEquality.ts, 0, 62))
+>a : Symbol(a, Decl(typeGuardOfFormFunctionEquality.ts, 2, 27))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>a : Symbol(a, Decl(typeGuardOfFormFunctionEquality.ts, 2, 27))
+
+switch (isString1(0, "")) {
+>isString1 : Symbol(isString1, Decl(typeGuardOfFormFunctionEquality.ts, 0, 0))
+
+    case isString2(""):
+>isString2 : Symbol(isString2, Decl(typeGuardOfFormFunctionEquality.ts, 0, 62))
+
+    default:
+}
+
+var x = isString1(0, "") === isString2("");
+>x : Symbol(x, Decl(typeGuardOfFormFunctionEquality.ts, 9, 3))
+>isString1 : Symbol(isString1, Decl(typeGuardOfFormFunctionEquality.ts, 0, 0))
+>isString2 : Symbol(isString2, Decl(typeGuardOfFormFunctionEquality.ts, 0, 62))
+
+function isString3(a: number, b: number, c: Object): c is string {
+>isString3 : Symbol(isString3, Decl(typeGuardOfFormFunctionEquality.ts, 9, 43))
+>a : Symbol(a, Decl(typeGuardOfFormFunctionEquality.ts, 11, 19))
+>b : Symbol(b, Decl(typeGuardOfFormFunctionEquality.ts, 11, 29))
+>c : Symbol(c, Decl(typeGuardOfFormFunctionEquality.ts, 11, 40))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>c : Symbol(c, Decl(typeGuardOfFormFunctionEquality.ts, 11, 40))
+
+    return isString1(0, c);
+>isString1 : Symbol(isString1, Decl(typeGuardOfFormFunctionEquality.ts, 0, 0))
+>c : Symbol(c, Decl(typeGuardOfFormFunctionEquality.ts, 11, 40))
+}
+
diff --git a/tests/baselines/reference/typeGuardOfFormFunctionEquality.types b/tests/baselines/reference/typeGuardOfFormFunctionEquality.types
new file mode 100644
index 00000000000..55f2e2aac0e
--- /dev/null
+++ b/tests/baselines/reference/typeGuardOfFormFunctionEquality.types
@@ -0,0 +1,54 @@
+=== tests/cases/conformance/expressions/typeGuards/typeGuardOfFormFunctionEquality.ts ===
+declare function isString1(a: number, b: Object): b is string;
+>isString1 : (a: number, b: Object) => b is string
+>a : number
+>b : Object
+>Object : Object
+>b : any
+
+declare function isString2(a: Object): a is string;
+>isString2 : (a: Object) => a is string
+>a : Object
+>Object : Object
+>a : any
+
+switch (isString1(0, "")) {
+>isString1(0, "") : boolean
+>isString1 : (a: number, b: Object) => b is string
+>0 : number
+>"" : string
+
+    case isString2(""):
+>isString2("") : boolean
+>isString2 : (a: Object) => a is string
+>"" : string
+
+    default:
+}
+
+var x = isString1(0, "") === isString2("");
+>x : boolean
+>isString1(0, "") === isString2("") : boolean
+>isString1(0, "") : boolean
+>isString1 : (a: number, b: Object) => b is string
+>0 : number
+>"" : string
+>isString2("") : boolean
+>isString2 : (a: Object) => a is string
+>"" : string
+
+function isString3(a: number, b: number, c: Object): c is string {
+>isString3 : (a: number, b: number, c: Object) => c is string
+>a : number
+>b : number
+>c : Object
+>Object : Object
+>c : any
+
+    return isString1(0, c);
+>isString1(0, c) : boolean
+>isString1 : (a: number, b: Object) => b is string
+>0 : number
+>c : Object
+}
+
diff --git a/tests/baselines/reference/typeGuardOfFormIsType.types b/tests/baselines/reference/typeGuardOfFormIsType.types
index aa8f8cc7d60..e2059be7b63 100644
--- a/tests/baselines/reference/typeGuardOfFormIsType.types
+++ b/tests/baselines/reference/typeGuardOfFormIsType.types
@@ -67,7 +67,7 @@ str = isC1(c1Orc2) && c1Orc2.p1; // C1
 >str = isC1(c1Orc2) && c1Orc2.p1 : string
 >str : string
 >isC1(c1Orc2) && c1Orc2.p1 : string
->isC1(c1Orc2) : x is C1
+>isC1(c1Orc2) : boolean
 >isC1 : (x: any) => x is C1
 >c1Orc2 : C1 | C2
 >c1Orc2.p1 : string
@@ -78,7 +78,7 @@ num = isC2(c1Orc2) && c1Orc2.p2; // C2
 >num = isC2(c1Orc2) && c1Orc2.p2 : number
 >num : number
 >isC2(c1Orc2) && c1Orc2.p2 : number
->isC2(c1Orc2) : x is C2
+>isC2(c1Orc2) : boolean
 >isC2 : (x: any) => x is C2
 >c1Orc2 : C1 | C2
 >c1Orc2.p2 : number
@@ -89,7 +89,7 @@ str = isD1(c1Orc2) && c1Orc2.p1; // D1
 >str = isD1(c1Orc2) && c1Orc2.p1 : string
 >str : string
 >isD1(c1Orc2) && c1Orc2.p1 : string
->isD1(c1Orc2) : x is D1
+>isD1(c1Orc2) : boolean
 >isD1 : (x: any) => x is D1
 >c1Orc2 : C1 | C2
 >c1Orc2.p1 : string
@@ -100,7 +100,7 @@ num = isD1(c1Orc2) && c1Orc2.p3; // D1
 >num = isD1(c1Orc2) && c1Orc2.p3 : number
 >num : number
 >isD1(c1Orc2) && c1Orc2.p3 : number
->isD1(c1Orc2) : x is D1
+>isD1(c1Orc2) : boolean
 >isD1 : (x: any) => x is D1
 >c1Orc2 : C1 | C2
 >c1Orc2.p3 : number
@@ -116,7 +116,7 @@ num = isC2(c2Ord1) && c2Ord1.p2; // C2
 >num = isC2(c2Ord1) && c2Ord1.p2 : number
 >num : number
 >isC2(c2Ord1) && c2Ord1.p2 : number
->isC2(c2Ord1) : x is C2
+>isC2(c2Ord1) : boolean
 >isC2 : (x: any) => x is C2
 >c2Ord1 : C2 | D1
 >c2Ord1.p2 : number
@@ -127,7 +127,7 @@ num = isD1(c2Ord1) && c2Ord1.p3; // D1
 >num = isD1(c2Ord1) && c2Ord1.p3 : number
 >num : number
 >isD1(c2Ord1) && c2Ord1.p3 : number
->isD1(c2Ord1) : x is D1
+>isD1(c2Ord1) : boolean
 >isD1 : (x: any) => x is D1
 >c2Ord1 : C2 | D1
 >c2Ord1.p3 : number
@@ -138,7 +138,7 @@ str = isD1(c2Ord1) && c2Ord1.p1; // D1
 >str = isD1(c2Ord1) && c2Ord1.p1 : string
 >str : string
 >isD1(c2Ord1) && c2Ord1.p1 : string
->isD1(c2Ord1) : x is D1
+>isD1(c2Ord1) : boolean
 >isD1 : (x: any) => x is D1
 >c2Ord1 : C2 | D1
 >c2Ord1.p1 : string
@@ -150,7 +150,7 @@ var r2: C2 | D1 = isC1(c2Ord1) && c2Ord1; // C2 | D1
 >C2 : C2
 >D1 : D1
 >isC1(c2Ord1) && c2Ord1 : D1
->isC1(c2Ord1) : x is C1
+>isC1(c2Ord1) : boolean
 >isC1 : (x: any) => x is C1
 >c2Ord1 : C2 | D1
 >c2Ord1 : D1
diff --git a/tests/baselines/reference/typeGuardOfFormIsTypeOnInterfaces.types b/tests/baselines/reference/typeGuardOfFormIsTypeOnInterfaces.types
index 4e28e6a4d38..ea169e95413 100644
--- a/tests/baselines/reference/typeGuardOfFormIsTypeOnInterfaces.types
+++ b/tests/baselines/reference/typeGuardOfFormIsTypeOnInterfaces.types
@@ -98,7 +98,7 @@ str = isC1(c1Orc2) && c1Orc2.p1; // C1
 >str = isC1(c1Orc2) && c1Orc2.p1 : string
 >str : string
 >isC1(c1Orc2) && c1Orc2.p1 : string
->isC1(c1Orc2) : x is C1
+>isC1(c1Orc2) : boolean
 >isC1 : (x: any) => x is C1
 >c1Orc2 : C1 | C2
 >c1Orc2.p1 : string
@@ -109,7 +109,7 @@ num = isC2(c1Orc2) && c1Orc2.p2; // C2
 >num = isC2(c1Orc2) && c1Orc2.p2 : number
 >num : number
 >isC2(c1Orc2) && c1Orc2.p2 : number
->isC2(c1Orc2) : x is C2
+>isC2(c1Orc2) : boolean
 >isC2 : (x: any) => x is C2
 >c1Orc2 : C1 | C2
 >c1Orc2.p2 : number
@@ -120,7 +120,7 @@ str = isD1(c1Orc2) && c1Orc2.p1; // D1
 >str = isD1(c1Orc2) && c1Orc2.p1 : string
 >str : string
 >isD1(c1Orc2) && c1Orc2.p1 : string
->isD1(c1Orc2) : x is D1
+>isD1(c1Orc2) : boolean
 >isD1 : (x: any) => x is D1
 >c1Orc2 : C1 | C2
 >c1Orc2.p1 : string
@@ -131,7 +131,7 @@ num = isD1(c1Orc2) && c1Orc2.p3; // D1
 >num = isD1(c1Orc2) && c1Orc2.p3 : number
 >num : number
 >isD1(c1Orc2) && c1Orc2.p3 : number
->isD1(c1Orc2) : x is D1
+>isD1(c1Orc2) : boolean
 >isD1 : (x: any) => x is D1
 >c1Orc2 : C1 | C2
 >c1Orc2.p3 : number
@@ -147,7 +147,7 @@ num = isC2(c2Ord1) && c2Ord1.p2; // C2
 >num = isC2(c2Ord1) && c2Ord1.p2 : number
 >num : number
 >isC2(c2Ord1) && c2Ord1.p2 : number
->isC2(c2Ord1) : x is C2
+>isC2(c2Ord1) : boolean
 >isC2 : (x: any) => x is C2
 >c2Ord1 : C2 | D1
 >c2Ord1.p2 : number
@@ -158,7 +158,7 @@ num = isD1(c2Ord1) && c2Ord1.p3; // D1
 >num = isD1(c2Ord1) && c2Ord1.p3 : number
 >num : number
 >isD1(c2Ord1) && c2Ord1.p3 : number
->isD1(c2Ord1) : x is D1
+>isD1(c2Ord1) : boolean
 >isD1 : (x: any) => x is D1
 >c2Ord1 : C2 | D1
 >c2Ord1.p3 : number
@@ -169,7 +169,7 @@ str = isD1(c2Ord1) && c2Ord1.p1; // D1
 >str = isD1(c2Ord1) && c2Ord1.p1 : string
 >str : string
 >isD1(c2Ord1) && c2Ord1.p1 : string
->isD1(c2Ord1) : x is D1
+>isD1(c2Ord1) : boolean
 >isD1 : (x: any) => x is D1
 >c2Ord1 : C2 | D1
 >c2Ord1.p1 : string
@@ -181,7 +181,7 @@ var r2: C2 | D1 = isC1(c2Ord1) && c2Ord1; // C2 | D1
 >C2 : C2
 >D1 : D1
 >isC1(c2Ord1) && c2Ord1 : D1
->isC1(c2Ord1) : x is C1
+>isC1(c2Ord1) : boolean
 >isC1 : (x: any) => x is C1
 >c2Ord1 : C2 | D1
 >c2Ord1 : D1
diff --git a/tests/baselines/reference/typeGuardOfFormThisMember.errors.txt b/tests/baselines/reference/typeGuardOfFormThisMember.errors.txt
new file mode 100644
index 00000000000..21dc896fbd9
--- /dev/null
+++ b/tests/baselines/reference/typeGuardOfFormThisMember.errors.txt
@@ -0,0 +1,130 @@
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(4,10): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(5,17): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(11,22): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(14,16): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(34,8): error TS2339: Property 'content' does not exist on type 'FileSystemObject'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(36,9): error TS2339: Property 'host' does not exist on type 'FileSystemObject'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(37,9): error TS2339: Property 'content' does not exist on type 'FileSystemObject'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(41,8): error TS2339: Property 'children' does not exist on type 'FileSystemObject'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(44,8): error TS2339: Property 'host' does not exist on type 'FileSystemObject'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(57,13): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(58,15): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(63,9): error TS2339: Property 'lead' does not exist on type 'GenericGuard<File>'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(66,9): error TS2339: Property 'follow' does not exist on type 'GenericGuard<File>'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(70,19): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts(79,11): error TS2339: Property 'do' does not exist on type 'SpecificGuard'.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts (15 errors) ====
+    // There's a 'File' class in the stdlib, wrap with a namespace to avoid collision
+    namespace Test {
+    	export class FileSystemObject {
+    		isFSO: this is FileSystemObject;
+    		       ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
+    		get isFile(): this is File {
+    		              ~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
+    			return this instanceof File;
+    		}
+    		set isFile(param) {
+    			// noop
+    		}
+    		get isDirectory(): this is Directory {
+    		                   ~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
+    			return this instanceof Directory;
+    		}
+    		isNetworked: this is (Networked & this);
+    		             ~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
+    		constructor(public path: string) {}
+    	}
+    
+    	export class File extends FileSystemObject {
+    		constructor(path: string, public content: string) { super(path); }
+    	}
+    	export class Directory extends FileSystemObject {
+    		children: FileSystemObject[];
+    	}
+    	export interface Networked {
+    		host: string;
+    	}
+    
+    	let file: FileSystemObject = new File("foo/bar.txt", "foo");
+    	file.isNetworked = false;
+    	file.isFSO = file.isFile;
+    	file.isFile = true;
+    	let x = file.isFile;
+    	if (file.isFile) {
+    		file.content;
+    		     ~~~~~~~
+!!! error TS2339: Property 'content' does not exist on type 'FileSystemObject'.
+    		if (file.isNetworked) {
+    			file.host;
+    			     ~~~~
+!!! error TS2339: Property 'host' does not exist on type 'FileSystemObject'.
+    			file.content;
+    			     ~~~~~~~
+!!! error TS2339: Property 'content' does not exist on type 'FileSystemObject'.
+    		}
+    	}
+    	else if (file.isDirectory) {
+    		file.children;
+    		     ~~~~~~~~
+!!! error TS2339: Property 'children' does not exist on type 'FileSystemObject'.
+    	}
+    	else if (file.isNetworked) {
+    		file.host;
+    		     ~~~~
+!!! error TS2339: Property 'host' does not exist on type 'FileSystemObject'.
+    	}
+    	
+    	interface GenericLeadGuard<T> extends GenericGuard<T> {
+    		lead(): void;
+    	}
+    	
+    	interface GenericFollowerGuard<T> extends GenericGuard<T> {
+    		follow(): void;
+    	}
+    	
+    	interface GenericGuard<T> {
+    		target: T;
+    		isLeader: this is (GenericLeadGuard<T>);
+    		          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
+    		isFollower: this is GenericFollowerGuard<T>;
+    		            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
+    	}
+    
+    	let guard: GenericGuard<File>;
+    	if (guard.isLeader) {
+    		guard.lead();
+    		      ~~~~
+!!! error TS2339: Property 'lead' does not exist on type 'GenericGuard<File>'.
+    	}
+    	else if (guard.isFollower) {
+    		guard.follow();
+    		      ~~~~~~
+!!! error TS2339: Property 'follow' does not exist on type 'GenericGuard<File>'.
+    	}
+    
+    	interface SpecificGuard {
+    		isMoreSpecific: this is MoreSpecificGuard;
+    		                ~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
+    	}
+    
+    	interface MoreSpecificGuard extends SpecificGuard {
+    		do(): void;
+    	}
+    
+    	let general: SpecificGuard;
+    	if (general.isMoreSpecific) {
+    		general.do();
+    		        ~~
+!!! error TS2339: Property 'do' does not exist on type 'SpecificGuard'.
+    	}
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typeGuardOfFormThisMember.symbols b/tests/baselines/reference/typeGuardOfFormThisMember.symbols
deleted file mode 100644
index 50e15b68ca4..00000000000
--- a/tests/baselines/reference/typeGuardOfFormThisMember.symbols
+++ /dev/null
@@ -1,240 +0,0 @@
-=== tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts ===
-// There's a 'File' class in the stdlib, wrap with a namespace to avoid collision
-namespace Test {
->Test : Symbol(Test, Decl(typeGuardOfFormThisMember.ts, 0, 0))
-
-	export class FileSystemObject {
->FileSystemObject : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
-
-		isFSO: this is FileSystemObject;
->isFSO : Symbol(isFSO, Decl(typeGuardOfFormThisMember.ts, 2, 32))
->FileSystemObject : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
-
-		get isFile(): this is File {
->isFile : Symbol(isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
->File : Symbol(File, Decl(typeGuardOfFormThisMember.ts, 15, 2))
-
-			return this instanceof File;
->this : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
->File : Symbol(File, Decl(typeGuardOfFormThisMember.ts, 15, 2))
-		}
-		set isFile(param) {
->isFile : Symbol(isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
->param : Symbol(param, Decl(typeGuardOfFormThisMember.ts, 7, 13))
-
-			// noop
-		}
-		get isDirectory(): this is Directory {
->isDirectory : Symbol(isDirectory, Decl(typeGuardOfFormThisMember.ts, 9, 3))
->Directory : Symbol(Directory, Decl(typeGuardOfFormThisMember.ts, 19, 2))
-
-			return this instanceof Directory;
->this : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
->Directory : Symbol(Directory, Decl(typeGuardOfFormThisMember.ts, 19, 2))
-		}
-		isNetworked: this is (Networked & this);
->isNetworked : Symbol(isNetworked, Decl(typeGuardOfFormThisMember.ts, 12, 3))
->Networked : Symbol(Networked, Decl(typeGuardOfFormThisMember.ts, 22, 2))
-
-		constructor(public path: string) {}
->path : Symbol(path, Decl(typeGuardOfFormThisMember.ts, 14, 14))
-	}
-
-	export class File extends FileSystemObject {
->File : Symbol(File, Decl(typeGuardOfFormThisMember.ts, 15, 2))
->FileSystemObject : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
-
-		constructor(path: string, public content: string) { super(path); }
->path : Symbol(path, Decl(typeGuardOfFormThisMember.ts, 18, 14))
->content : Symbol(content, Decl(typeGuardOfFormThisMember.ts, 18, 27))
->super : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
->path : Symbol(path, Decl(typeGuardOfFormThisMember.ts, 18, 14))
-	}
-	export class Directory extends FileSystemObject {
->Directory : Symbol(Directory, Decl(typeGuardOfFormThisMember.ts, 19, 2))
->FileSystemObject : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
-
-		children: FileSystemObject[];
->children : Symbol(children, Decl(typeGuardOfFormThisMember.ts, 20, 50))
->FileSystemObject : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
-	}
-	export interface Networked {
->Networked : Symbol(Networked, Decl(typeGuardOfFormThisMember.ts, 22, 2))
-
-		host: string;
->host : Symbol(host, Decl(typeGuardOfFormThisMember.ts, 23, 29))
-	}
-
-	let file: FileSystemObject = new File("foo/bar.txt", "foo");
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->FileSystemObject : Symbol(FileSystemObject, Decl(typeGuardOfFormThisMember.ts, 1, 16))
->File : Symbol(File, Decl(typeGuardOfFormThisMember.ts, 15, 2))
-
-	file.isNetworked = false;
->file.isNetworked : Symbol(FileSystemObject.isNetworked, Decl(typeGuardOfFormThisMember.ts, 12, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isNetworked : Symbol(FileSystemObject.isNetworked, Decl(typeGuardOfFormThisMember.ts, 12, 3))
-
-	file.isFSO = file.isFile;
->file.isFSO : Symbol(FileSystemObject.isFSO, Decl(typeGuardOfFormThisMember.ts, 2, 32))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isFSO : Symbol(FileSystemObject.isFSO, Decl(typeGuardOfFormThisMember.ts, 2, 32))
->file.isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
-
-	file.isFile = true;
->file.isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
-
-	let x = file.isFile;
->x : Symbol(x, Decl(typeGuardOfFormThisMember.ts, 31, 4))
->file.isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
-
-	if (file.isFile) {
->file.isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isFile : Symbol(FileSystemObject.isFile, Decl(typeGuardOfFormThisMember.ts, 3, 34), Decl(typeGuardOfFormThisMember.ts, 6, 3))
-
-		file.content;
->file.content : Symbol(File.content, Decl(typeGuardOfFormThisMember.ts, 18, 27))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->content : Symbol(File.content, Decl(typeGuardOfFormThisMember.ts, 18, 27))
-
-		if (file.isNetworked) {
->file.isNetworked : Symbol(FileSystemObject.isNetworked, Decl(typeGuardOfFormThisMember.ts, 12, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isNetworked : Symbol(FileSystemObject.isNetworked, Decl(typeGuardOfFormThisMember.ts, 12, 3))
-
-			file.host;
->file.host : Symbol(Networked.host, Decl(typeGuardOfFormThisMember.ts, 23, 29))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->host : Symbol(Networked.host, Decl(typeGuardOfFormThisMember.ts, 23, 29))
-
-			file.content;
->file.content : Symbol(File.content, Decl(typeGuardOfFormThisMember.ts, 18, 27))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->content : Symbol(File.content, Decl(typeGuardOfFormThisMember.ts, 18, 27))
-		}
-	}
-	else if (file.isDirectory) {
->file.isDirectory : Symbol(FileSystemObject.isDirectory, Decl(typeGuardOfFormThisMember.ts, 9, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isDirectory : Symbol(FileSystemObject.isDirectory, Decl(typeGuardOfFormThisMember.ts, 9, 3))
-
-		file.children;
->file.children : Symbol(Directory.children, Decl(typeGuardOfFormThisMember.ts, 20, 50))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->children : Symbol(Directory.children, Decl(typeGuardOfFormThisMember.ts, 20, 50))
-	}
-	else if (file.isNetworked) {
->file.isNetworked : Symbol(FileSystemObject.isNetworked, Decl(typeGuardOfFormThisMember.ts, 12, 3))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->isNetworked : Symbol(FileSystemObject.isNetworked, Decl(typeGuardOfFormThisMember.ts, 12, 3))
-
-		file.host;
->file.host : Symbol(Networked.host, Decl(typeGuardOfFormThisMember.ts, 23, 29))
->file : Symbol(file, Decl(typeGuardOfFormThisMember.ts, 27, 4))
->host : Symbol(Networked.host, Decl(typeGuardOfFormThisMember.ts, 23, 29))
-	}
-	
-	interface GenericLeadGuard<T> extends GenericGuard<T> {
->GenericLeadGuard : Symbol(GenericLeadGuard, Decl(typeGuardOfFormThisMember.ts, 44, 2))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 46, 28))
->GenericGuard : Symbol(GenericGuard, Decl(typeGuardOfFormThisMember.ts, 52, 2))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 46, 28))
-
-		lead(): void;
->lead : Symbol(lead, Decl(typeGuardOfFormThisMember.ts, 46, 56))
-	}
-	
-	interface GenericFollowerGuard<T> extends GenericGuard<T> {
->GenericFollowerGuard : Symbol(GenericFollowerGuard, Decl(typeGuardOfFormThisMember.ts, 48, 2))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 50, 32))
->GenericGuard : Symbol(GenericGuard, Decl(typeGuardOfFormThisMember.ts, 52, 2))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 50, 32))
-
-		follow(): void;
->follow : Symbol(follow, Decl(typeGuardOfFormThisMember.ts, 50, 60))
-	}
-	
-	interface GenericGuard<T> {
->GenericGuard : Symbol(GenericGuard, Decl(typeGuardOfFormThisMember.ts, 52, 2))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 54, 24))
-
-		target: T;
->target : Symbol(target, Decl(typeGuardOfFormThisMember.ts, 54, 28))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 54, 24))
-
-		isLeader: this is (GenericLeadGuard<T>);
->isLeader : Symbol(isLeader, Decl(typeGuardOfFormThisMember.ts, 55, 12))
->GenericLeadGuard : Symbol(GenericLeadGuard, Decl(typeGuardOfFormThisMember.ts, 44, 2))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 54, 24))
-
-		isFollower: this is GenericFollowerGuard<T>;
->isFollower : Symbol(isFollower, Decl(typeGuardOfFormThisMember.ts, 56, 42))
->GenericFollowerGuard : Symbol(GenericFollowerGuard, Decl(typeGuardOfFormThisMember.ts, 48, 2))
->T : Symbol(T, Decl(typeGuardOfFormThisMember.ts, 54, 24))
-	}
-
-	let guard: GenericGuard<File>;
->guard : Symbol(guard, Decl(typeGuardOfFormThisMember.ts, 60, 4))
->GenericGuard : Symbol(GenericGuard, Decl(typeGuardOfFormThisMember.ts, 52, 2))
->File : Symbol(File, Decl(typeGuardOfFormThisMember.ts, 15, 2))
-
-	if (guard.isLeader) {
->guard.isLeader : Symbol(GenericGuard.isLeader, Decl(typeGuardOfFormThisMember.ts, 55, 12))
->guard : Symbol(guard, Decl(typeGuardOfFormThisMember.ts, 60, 4))
->isLeader : Symbol(GenericGuard.isLeader, Decl(typeGuardOfFormThisMember.ts, 55, 12))
-
-		guard.lead();
->guard.lead : Symbol(GenericLeadGuard.lead, Decl(typeGuardOfFormThisMember.ts, 46, 56))
->guard : Symbol(guard, Decl(typeGuardOfFormThisMember.ts, 60, 4))
->lead : Symbol(GenericLeadGuard.lead, Decl(typeGuardOfFormThisMember.ts, 46, 56))
-	}
-	else if (guard.isFollower) {
->guard.isFollower : Symbol(GenericGuard.isFollower, Decl(typeGuardOfFormThisMember.ts, 56, 42))
->guard : Symbol(guard, Decl(typeGuardOfFormThisMember.ts, 60, 4))
->isFollower : Symbol(GenericGuard.isFollower, Decl(typeGuardOfFormThisMember.ts, 56, 42))
-
-		guard.follow();
->guard.follow : Symbol(GenericFollowerGuard.follow, Decl(typeGuardOfFormThisMember.ts, 50, 60))
->guard : Symbol(guard, Decl(typeGuardOfFormThisMember.ts, 60, 4))
->follow : Symbol(GenericFollowerGuard.follow, Decl(typeGuardOfFormThisMember.ts, 50, 60))
-	}
-
-	interface SpecificGuard {
->SpecificGuard : Symbol(SpecificGuard, Decl(typeGuardOfFormThisMember.ts, 66, 2))
-
-		isMoreSpecific: this is MoreSpecificGuard;
->isMoreSpecific : Symbol(isMoreSpecific, Decl(typeGuardOfFormThisMember.ts, 68, 26))
->MoreSpecificGuard : Symbol(MoreSpecificGuard, Decl(typeGuardOfFormThisMember.ts, 70, 2))
-	}
-
-	interface MoreSpecificGuard extends SpecificGuard {
->MoreSpecificGuard : Symbol(MoreSpecificGuard, Decl(typeGuardOfFormThisMember.ts, 70, 2))
->SpecificGuard : Symbol(SpecificGuard, Decl(typeGuardOfFormThisMember.ts, 66, 2))
-
-		do(): void;
->do : Symbol(do, Decl(typeGuardOfFormThisMember.ts, 72, 52))
-	}
-
-	let general: SpecificGuard;
->general : Symbol(general, Decl(typeGuardOfFormThisMember.ts, 76, 4))
->SpecificGuard : Symbol(SpecificGuard, Decl(typeGuardOfFormThisMember.ts, 66, 2))
-
-	if (general.isMoreSpecific) {
->general.isMoreSpecific : Symbol(SpecificGuard.isMoreSpecific, Decl(typeGuardOfFormThisMember.ts, 68, 26))
->general : Symbol(general, Decl(typeGuardOfFormThisMember.ts, 76, 4))
->isMoreSpecific : Symbol(SpecificGuard.isMoreSpecific, Decl(typeGuardOfFormThisMember.ts, 68, 26))
-
-		general.do();
->general.do : Symbol(MoreSpecificGuard.do, Decl(typeGuardOfFormThisMember.ts, 72, 52))
->general : Symbol(general, Decl(typeGuardOfFormThisMember.ts, 76, 4))
->do : Symbol(MoreSpecificGuard.do, Decl(typeGuardOfFormThisMember.ts, 72, 52))
-	}
-}
-
diff --git a/tests/baselines/reference/typeGuardOfFormThisMember.types b/tests/baselines/reference/typeGuardOfFormThisMember.types
deleted file mode 100644
index 68343947fb4..00000000000
--- a/tests/baselines/reference/typeGuardOfFormThisMember.types
+++ /dev/null
@@ -1,254 +0,0 @@
-=== tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMember.ts ===
-// There's a 'File' class in the stdlib, wrap with a namespace to avoid collision
-namespace Test {
->Test : typeof Test
-
-	export class FileSystemObject {
->FileSystemObject : FileSystemObject
-
-		isFSO: this is FileSystemObject;
->isFSO : this is FileSystemObject
->FileSystemObject : FileSystemObject
-
-		get isFile(): this is File {
->isFile : this is File
->File : File
-
-			return this instanceof File;
->this instanceof File : boolean
->this : this
->File : typeof File
-		}
-		set isFile(param) {
->isFile : this is File
->param : boolean
-
-			// noop
-		}
-		get isDirectory(): this is Directory {
->isDirectory : this is Directory
->Directory : Directory
-
-			return this instanceof Directory;
->this instanceof Directory : boolean
->this : this
->Directory : typeof Directory
-		}
-		isNetworked: this is (Networked & this);
->isNetworked : this is Networked & this
->Networked : Networked
-
-		constructor(public path: string) {}
->path : string
-	}
-
-	export class File extends FileSystemObject {
->File : File
->FileSystemObject : FileSystemObject
-
-		constructor(path: string, public content: string) { super(path); }
->path : string
->content : string
->super(path) : void
->super : typeof FileSystemObject
->path : string
-	}
-	export class Directory extends FileSystemObject {
->Directory : Directory
->FileSystemObject : FileSystemObject
-
-		children: FileSystemObject[];
->children : FileSystemObject[]
->FileSystemObject : FileSystemObject
-	}
-	export interface Networked {
->Networked : Networked
-
-		host: string;
->host : string
-	}
-
-	let file: FileSystemObject = new File("foo/bar.txt", "foo");
->file : FileSystemObject
->FileSystemObject : FileSystemObject
->new File("foo/bar.txt", "foo") : File
->File : typeof File
->"foo/bar.txt" : string
->"foo" : string
-
-	file.isNetworked = false;
->file.isNetworked = false : boolean
->file.isNetworked : this is Networked & FileSystemObject
->file : FileSystemObject
->isNetworked : this is Networked & FileSystemObject
->false : boolean
-
-	file.isFSO = file.isFile;
->file.isFSO = file.isFile : this is File
->file.isFSO : this is FileSystemObject
->file : FileSystemObject
->isFSO : this is FileSystemObject
->file.isFile : this is File
->file : FileSystemObject
->isFile : this is File
-
-	file.isFile = true;
->file.isFile = true : boolean
->file.isFile : this is File
->file : FileSystemObject
->isFile : this is File
->true : boolean
-
-	let x = file.isFile;
->x : boolean
->file.isFile : this is File
->file : FileSystemObject
->isFile : this is File
-
-	if (file.isFile) {
->file.isFile : this is File
->file : FileSystemObject
->isFile : this is File
-
-		file.content;
->file.content : string
->file : File
->content : string
-
-		if (file.isNetworked) {
->file.isNetworked : this is Networked & File
->file : File
->isNetworked : this is Networked & File
-
-			file.host;
->file.host : string
->file : Networked & File
->host : string
-
-			file.content;
->file.content : string
->file : Networked & File
->content : string
-		}
-	}
-	else if (file.isDirectory) {
->file.isDirectory : this is Directory
->file : FileSystemObject
->isDirectory : this is Directory
-
-		file.children;
->file.children : FileSystemObject[]
->file : Directory
->children : FileSystemObject[]
-	}
-	else if (file.isNetworked) {
->file.isNetworked : this is Networked & FileSystemObject
->file : FileSystemObject
->isNetworked : this is Networked & FileSystemObject
-
-		file.host;
->file.host : string
->file : Networked & FileSystemObject
->host : string
-	}
-	
-	interface GenericLeadGuard<T> extends GenericGuard<T> {
->GenericLeadGuard : GenericLeadGuard<T>
->T : T
->GenericGuard : GenericGuard<T>
->T : T
-
-		lead(): void;
->lead : () => void
-	}
-	
-	interface GenericFollowerGuard<T> extends GenericGuard<T> {
->GenericFollowerGuard : GenericFollowerGuard<T>
->T : T
->GenericGuard : GenericGuard<T>
->T : T
-
-		follow(): void;
->follow : () => void
-	}
-	
-	interface GenericGuard<T> {
->GenericGuard : GenericGuard<T>
->T : T
-
-		target: T;
->target : T
->T : T
-
-		isLeader: this is (GenericLeadGuard<T>);
->isLeader : this is GenericLeadGuard<T>
->GenericLeadGuard : GenericLeadGuard<T>
->T : T
-
-		isFollower: this is GenericFollowerGuard<T>;
->isFollower : this is GenericFollowerGuard<T>
->GenericFollowerGuard : GenericFollowerGuard<T>
->T : T
-	}
-
-	let guard: GenericGuard<File>;
->guard : GenericGuard<File>
->GenericGuard : GenericGuard<T>
->File : File
-
-	if (guard.isLeader) {
->guard.isLeader : this is GenericLeadGuard<File>
->guard : GenericGuard<File>
->isLeader : this is GenericLeadGuard<File>
-
-		guard.lead();
->guard.lead() : void
->guard.lead : () => void
->guard : GenericLeadGuard<File>
->lead : () => void
-	}
-	else if (guard.isFollower) {
->guard.isFollower : this is GenericFollowerGuard<File>
->guard : GenericGuard<File>
->isFollower : this is GenericFollowerGuard<File>
-
-		guard.follow();
->guard.follow() : void
->guard.follow : () => void
->guard : GenericFollowerGuard<File>
->follow : () => void
-	}
-
-	interface SpecificGuard {
->SpecificGuard : SpecificGuard
-
-		isMoreSpecific: this is MoreSpecificGuard;
->isMoreSpecific : this is MoreSpecificGuard
->MoreSpecificGuard : MoreSpecificGuard
-	}
-
-	interface MoreSpecificGuard extends SpecificGuard {
->MoreSpecificGuard : MoreSpecificGuard
->SpecificGuard : SpecificGuard
-
-		do(): void;
->do : () => void
-	}
-
-	let general: SpecificGuard;
->general : SpecificGuard
->SpecificGuard : SpecificGuard
-
-	if (general.isMoreSpecific) {
->general.isMoreSpecific : this is MoreSpecificGuard
->general : SpecificGuard
->isMoreSpecific : this is MoreSpecificGuard
-
-		general.do();
->general.do() : void
->general.do : () => void
->general : MoreSpecificGuard
->do : () => void
-	}
-}
-
diff --git a/tests/baselines/reference/typeGuardOfFormThisMemberErrors.errors.txt b/tests/baselines/reference/typeGuardOfFormThisMemberErrors.errors.txt
index 754cbffe6e6..88e9d41cc7b 100644
--- a/tests/baselines/reference/typeGuardOfFormThisMemberErrors.errors.txt
+++ b/tests/baselines/reference/typeGuardOfFormThisMemberErrors.errors.txt
@@ -1,27 +1,32 @@
-tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts(29,2): error TS1226: Type predicate 'this is File' is not assignable to 'this is Networked & FileSystemObject'.
-  Type 'File' is not assignable to type 'Networked & FileSystemObject'.
-    Type 'File' is not assignable to type 'Networked'.
-      Property 'host' is missing in type 'File'.
-tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts(31,2): error TS1226: Type predicate 'this is FileSystemObject' is not assignable to 'this is File'.
-  Type 'FileSystemObject' is not assignable to type 'File'.
-    Property 'content' is missing in type 'FileSystemObject'.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts(4,10): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts(5,17): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts(11,22): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts(14,16): error TS1228: A type predicate is only allowed in return type position for functions and methods.
 
 
-==== tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts (2 errors) ====
+==== tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.ts (4 errors) ====
     // There's a 'File' class in the stdlib, wrap with a namespace to avoid collision
     namespace Test {
     	export class FileSystemObject {
     		isFSO: this is FileSystemObject;
+    		       ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
     		get isFile(): this is File {
+    		              ~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
     			return this instanceof File;
     		}
     		set isFile(param) {
     			// noop
     		}
     		get isDirectory(): this is Directory {
+    		                   ~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
     			return this instanceof Directory;
     		}
     		isNetworked: this is (Networked & this);
+    		             ~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
     		constructor(public path: string) {}
     	}
     
@@ -37,15 +42,6 @@ tests/cases/conformance/expressions/typeGuards/typeGuardOfFormThisMemberErrors.t
     
     	let file: FileSystemObject = new File("foo/bar.txt", "foo");
     	file.isNetworked = file.isFile;
-    	~~~~~~~~~~~~~~~~
-!!! error TS1226: Type predicate 'this is File' is not assignable to 'this is Networked & FileSystemObject'.
-!!! error TS1226:   Type 'File' is not assignable to type 'Networked & FileSystemObject'.
-!!! error TS1226:     Type 'File' is not assignable to type 'Networked'.
-!!! error TS1226:       Property 'host' is missing in type 'File'.
     	file.isFSO = file.isNetworked;
     	file.isFile = file.isFSO;
-    	~~~~~~~~~~~
-!!! error TS1226: Type predicate 'this is FileSystemObject' is not assignable to 'this is File'.
-!!! error TS1226:   Type 'FileSystemObject' is not assignable to type 'File'.
-!!! error TS1226:     Property 'content' is missing in type 'FileSystemObject'.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/typeParameterFixingWithConstraints.types b/tests/baselines/reference/typeParameterFixingWithConstraints.types
index 22d294f9d2e..1e71f439e5e 100644
--- a/tests/baselines/reference/typeParameterFixingWithConstraints.types
+++ b/tests/baselines/reference/typeParameterFixingWithConstraints.types
@@ -31,17 +31,17 @@ var foo: IFoo;
 >IFoo : IFoo
 
 foo.foo({ bar: null }, bar => null, bar => null);
->foo.foo({ bar: null }, bar => null, bar => null) : { [x: string]: any; bar: any; }
+>foo.foo({ bar: null }, bar => null, bar => null) : { bar: any; }
 >foo.foo : <TBar extends IBar>(bar: TBar, bar1: (bar: TBar) => TBar, bar2: (bar: TBar) => TBar) => TBar
 >foo : IFoo
 >foo : <TBar extends IBar>(bar: TBar, bar1: (bar: TBar) => TBar, bar2: (bar: TBar) => TBar) => TBar
->{ bar: null } : { [x: string]: null; bar: null; }
+>{ bar: null } : { bar: null; }
 >bar : null
 >null : null
->bar => null : (bar: { [x: string]: any; bar: any; }) => any
->bar : { [x: string]: any; bar: any; }
+>bar => null : (bar: { bar: any; }) => any
+>bar : { bar: any; }
 >null : null
->bar => null : (bar: { [x: string]: any; bar: any; }) => any
->bar : { [x: string]: any; bar: any; }
+>bar => null : (bar: { bar: any; }) => any
+>bar : { bar: any; }
 >null : null
 
diff --git a/tests/baselines/reference/typePredicateOnVariableDeclaration01.errors.txt b/tests/baselines/reference/typePredicateOnVariableDeclaration01.errors.txt
new file mode 100644
index 00000000000..b713dd12ae7
--- /dev/null
+++ b/tests/baselines/reference/typePredicateOnVariableDeclaration01.errors.txt
@@ -0,0 +1,8 @@
+tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration01.ts(2,8): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration01.ts (1 errors) ====
+    
+    var x: this is string;
+           ~~~~~~~~~~~~~~
+!!! error TS1228: A type predicate is only allowed in return type position for functions and methods.
\ No newline at end of file
diff --git a/tests/baselines/reference/typePredicateOnVariableDeclaration01.js b/tests/baselines/reference/typePredicateOnVariableDeclaration01.js
new file mode 100644
index 00000000000..5831142cf5c
--- /dev/null
+++ b/tests/baselines/reference/typePredicateOnVariableDeclaration01.js
@@ -0,0 +1,10 @@
+//// [typePredicateOnVariableDeclaration01.ts]
+
+var x: this is string;
+
+//// [typePredicateOnVariableDeclaration01.js]
+var x;
+
+
+//// [typePredicateOnVariableDeclaration01.d.ts]
+declare var x: this is string;
diff --git a/tests/baselines/reference/typePredicateOnVariableDeclaration02.errors.txt b/tests/baselines/reference/typePredicateOnVariableDeclaration02.errors.txt
new file mode 100644
index 00000000000..af967b22b79
--- /dev/null
+++ b/tests/baselines/reference/typePredicateOnVariableDeclaration02.errors.txt
@@ -0,0 +1,20 @@
+tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts(2,8): error TS2304: Cannot find name 'z'.
+tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts(2,8): error TS4025: Exported variable 'y' has or is using private name 'z'.
+tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts(2,10): error TS1005: '=' expected.
+tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts(2,10): error TS2304: Cannot find name 'is'.
+tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts(2,13): error TS1005: ',' expected.
+
+
+==== tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts (5 errors) ====
+    
+    var y: z is number;
+           ~
+!!! error TS2304: Cannot find name 'z'.
+           ~
+!!! error TS4025: Exported variable 'y' has or is using private name 'z'.
+             ~~
+!!! error TS1005: '=' expected.
+             ~~
+!!! error TS2304: Cannot find name 'is'.
+                ~~~~~~
+!!! error TS1005: ',' expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/typePredicateOnVariableDeclaration02.js b/tests/baselines/reference/typePredicateOnVariableDeclaration02.js
new file mode 100644
index 00000000000..b28a89116ba
--- /dev/null
+++ b/tests/baselines/reference/typePredicateOnVariableDeclaration02.js
@@ -0,0 +1,6 @@
+//// [typePredicateOnVariableDeclaration02.ts]
+
+var y: z is number;
+
+//// [typePredicateOnVariableDeclaration02.js]
+var y = is, number;
diff --git a/tests/baselines/reference/typesWithPrivateConstructor.errors.txt b/tests/baselines/reference/typesWithPrivateConstructor.errors.txt
index 261038a1f4a..ab8ea4e26ad 100644
--- a/tests/baselines/reference/typesWithPrivateConstructor.errors.txt
+++ b/tests/baselines/reference/typesWithPrivateConstructor.errors.txt
@@ -1,36 +1,24 @@
-tests/cases/conformance/types/members/typesWithPrivateConstructor.ts(4,5): error TS1089: 'private' modifier cannot appear on a constructor declaration.
-tests/cases/conformance/types/members/typesWithPrivateConstructor.ts(8,5): error TS2322: Type 'Function' is not assignable to type '() => void'.
-  Type 'Function' provides no match for the signature '(): void'
-tests/cases/conformance/types/members/typesWithPrivateConstructor.ts(11,5): error TS1089: 'private' modifier cannot appear on a constructor declaration.
-tests/cases/conformance/types/members/typesWithPrivateConstructor.ts(12,5): error TS1089: 'private' modifier cannot appear on a constructor declaration.
-tests/cases/conformance/types/members/typesWithPrivateConstructor.ts(15,10): error TS2346: Supplied parameters do not match any signature of call target.
+tests/cases/conformance/types/members/typesWithPrivateConstructor.ts(6,9): error TS2673: Constructor of class 'C' is private and only accessible within the class declaration.
+tests/cases/conformance/types/members/typesWithPrivateConstructor.ts(14,10): error TS2673: Constructor of class 'C2' is private and only accessible within the class declaration.
 
 
-==== tests/cases/conformance/types/members/typesWithPrivateConstructor.ts (5 errors) ====
-    // private constructors are not allowed
+==== tests/cases/conformance/types/members/typesWithPrivateConstructor.ts (2 errors) ====
     
     class C {
         private constructor() { }
-        ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
     }
     
-    var c = new C();
+    var c = new C(); // error C is private
+            ~~~~~~~
+!!! error TS2673: Constructor of class 'C' is private and only accessible within the class declaration.
     var r: () => void = c.constructor;
-        ~
-!!! error TS2322: Type 'Function' is not assignable to type '() => void'.
-!!! error TS2322:   Type 'Function' provides no match for the signature '(): void'
     
     class C2 {
         private constructor(x: number);
-        ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
         private constructor(x: any) { }
-        ~~~~~~~
-!!! error TS1089: 'private' modifier cannot appear on a constructor declaration.
     }
     
-    var c2 = new C2();
+    var c2 = new C2(); // error C2 is private
              ~~~~~~~~
-!!! error TS2346: Supplied parameters do not match any signature of call target.
+!!! error TS2673: Constructor of class 'C2' is private and only accessible within the class declaration.
     var r2: (x: number) => void = c2.constructor;
\ No newline at end of file
diff --git a/tests/baselines/reference/typesWithPrivateConstructor.js b/tests/baselines/reference/typesWithPrivateConstructor.js
index d894eeda49a..1795ee6b316 100644
--- a/tests/baselines/reference/typesWithPrivateConstructor.js
+++ b/tests/baselines/reference/typesWithPrivateConstructor.js
@@ -1,11 +1,10 @@
 //// [typesWithPrivateConstructor.ts]
-// private constructors are not allowed
 
 class C {
     private constructor() { }
 }
 
-var c = new C();
+var c = new C(); // error C is private
 var r: () => void = c.constructor;
 
 class C2 {
@@ -13,22 +12,34 @@ class C2 {
     private constructor(x: any) { }
 }
 
-var c2 = new C2();
+var c2 = new C2(); // error C2 is private
 var r2: (x: number) => void = c2.constructor;
 
 //// [typesWithPrivateConstructor.js]
-// private constructors are not allowed
 var C = (function () {
     function C() {
     }
     return C;
 }());
-var c = new C();
+var c = new C(); // error C is private
 var r = c.constructor;
 var C2 = (function () {
     function C2(x) {
     }
     return C2;
 }());
-var c2 = new C2();
+var c2 = new C2(); // error C2 is private
 var r2 = c2.constructor;
+
+
+//// [typesWithPrivateConstructor.d.ts]
+declare class C {
+    private constructor();
+}
+declare var c: any;
+declare var r: () => void;
+declare class C2 {
+    private constructor(x);
+}
+declare var c2: any;
+declare var r2: (x: number) => void;
diff --git a/tests/baselines/reference/typesWithProtectedConstructor.errors.txt b/tests/baselines/reference/typesWithProtectedConstructor.errors.txt
new file mode 100644
index 00000000000..2a5a059f44d
--- /dev/null
+++ b/tests/baselines/reference/typesWithProtectedConstructor.errors.txt
@@ -0,0 +1,24 @@
+tests/cases/conformance/types/members/typesWithProtectedConstructor.ts(6,9): error TS2674: Constructor of class 'C' is protected and only accessible within the class declaration.
+tests/cases/conformance/types/members/typesWithProtectedConstructor.ts(14,10): error TS2674: Constructor of class 'C2' is protected and only accessible within the class declaration.
+
+
+==== tests/cases/conformance/types/members/typesWithProtectedConstructor.ts (2 errors) ====
+    
+    class C {
+        protected constructor() { }
+    }
+    
+    var c = new C(); // error C is protected
+            ~~~~~~~
+!!! error TS2674: Constructor of class 'C' is protected and only accessible within the class declaration.
+    var r: () => void = c.constructor;
+    
+    class C2 {
+        protected constructor(x: number);
+        protected constructor(x: any) { }
+    }
+    
+    var c2 = new C2(); // error C2 is protected
+             ~~~~~~~~
+!!! error TS2674: Constructor of class 'C2' is protected and only accessible within the class declaration.
+    var r2: (x: number) => void = c2.constructor;
\ No newline at end of file
diff --git a/tests/baselines/reference/typesWithProtectedConstructor.js b/tests/baselines/reference/typesWithProtectedConstructor.js
new file mode 100644
index 00000000000..e75b3b6ecd3
--- /dev/null
+++ b/tests/baselines/reference/typesWithProtectedConstructor.js
@@ -0,0 +1,45 @@
+//// [typesWithProtectedConstructor.ts]
+
+class C {
+    protected constructor() { }
+}
+
+var c = new C(); // error C is protected
+var r: () => void = c.constructor;
+
+class C2 {
+    protected constructor(x: number);
+    protected constructor(x: any) { }
+}
+
+var c2 = new C2(); // error C2 is protected
+var r2: (x: number) => void = c2.constructor;
+
+//// [typesWithProtectedConstructor.js]
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+var c = new C(); // error C is protected
+var r = c.constructor;
+var C2 = (function () {
+    function C2(x) {
+    }
+    return C2;
+}());
+var c2 = new C2(); // error C2 is protected
+var r2 = c2.constructor;
+
+
+//// [typesWithProtectedConstructor.d.ts]
+declare class C {
+    protected constructor();
+}
+declare var c: any;
+declare var r: () => void;
+declare class C2 {
+    protected constructor(x: number);
+}
+declare var c2: any;
+declare var r2: (x: number) => void;
diff --git a/tests/baselines/reference/underscoreTest1.types b/tests/baselines/reference/underscoreTest1.types
index 4d8a05a5c38..37f3bdb12ab 100644
--- a/tests/baselines/reference/underscoreTest1.types
+++ b/tests/baselines/reference/underscoreTest1.types
@@ -31,7 +31,7 @@ _.each({ one: 1, two: 2, three: 3 }, (value: number, key?: string) => alert(valu
 >_.each : { <T>(list: T[], iterator: Iterator<T, void>, context?: any): void; <T>(list: Dictionary<T>, iterator: Iterator<T, void>, context?: any): void; }
 >_ : Underscore.Static
 >each : { <T>(list: T[], iterator: Iterator<T, void>, context?: any): void; <T>(list: Dictionary<T>, iterator: Iterator<T, void>, context?: any): void; }
->{ one: 1, two: 2, three: 3 } : { [x: string]: number; one: number; two: number; three: number; }
+>{ one: 1, two: 2, three: 3 } : { one: number; two: number; three: number; }
 >one : number
 >1 : number
 >two : number
@@ -68,7 +68,7 @@ _.map({ one: 1, two: 2, three: 3 }, (value: number, key?: string) => value * 3);
 >_.map : { <T, U>(list: T[], iterator: Iterator<T, U>, context?: any): U[]; <T, U>(list: Dictionary<T>, iterator: Iterator<T, U>, context?: any): U[]; }
 >_ : Underscore.Static
 >map : { <T, U>(list: T[], iterator: Iterator<T, U>, context?: any): U[]; <T, U>(list: Dictionary<T>, iterator: Iterator<T, U>, context?: any): U[]; }
->{ one: 1, two: 2, three: 3 } : { [x: string]: number; one: number; two: number; three: number; }
+>{ one: 1, two: 2, three: 3 } : { one: number; two: number; three: number; }
 >one : number
 >1 : number
 >two : number
@@ -449,7 +449,7 @@ _.size({ one: 1, two: 2, three: 3 });
 >_.size : { <T>(list: T[]): number; <T>(list: Dictionary<T>): number; }
 >_ : Underscore.Static
 >size : { <T>(list: T[]): number; <T>(list: Dictionary<T>): number; }
->{ one: 1, two: 2, three: 3 } : { [x: string]: number; one: number; two: number; three: number; }
+>{ one: 1, two: 2, three: 3 } : { one: number; two: number; three: number; }
 >one : number
 >1 : number
 >two : number
diff --git a/tests/baselines/reference/unionAndIntersectionInference1.types b/tests/baselines/reference/unionAndIntersectionInference1.types
index 073a677b659..5d23688f0b7 100644
--- a/tests/baselines/reference/unionAndIntersectionInference1.types
+++ b/tests/baselines/reference/unionAndIntersectionInference1.types
@@ -110,7 +110,7 @@ function foo1<a>(value: void|a): void {
 >a : a
 
     if (isVoid(value)) {
->isVoid(value) : value is void
+>isVoid(value) : boolean
 >isVoid : <a>(value: void | a) => value is void
 >value : void | a
 
@@ -130,7 +130,7 @@ function baz1<a>(value: void|a): void {
 >a : a
 
       if (isNonVoid(value)) {
->isNonVoid(value) : value is a
+>isNonVoid(value) : boolean
 >isNonVoid : <a>(value: void | a) => value is a
 >value : void | a
 
diff --git a/tests/baselines/reference/widenedTypes.errors.txt b/tests/baselines/reference/widenedTypes.errors.txt
index 2277ef6eea7..beda634c2a6 100644
--- a/tests/baselines/reference/widenedTypes.errors.txt
+++ b/tests/baselines/reference/widenedTypes.errors.txt
@@ -6,8 +6,8 @@ tests/cases/compiler/widenedTypes.ts(11,1): error TS2322: Type 'string' is not a
 tests/cases/compiler/widenedTypes.ts(18,1): error TS2322: Type 'string' is not assignable to type 'number'.
 tests/cases/compiler/widenedTypes.ts(23,5): error TS2322: Type 'number[]' is not assignable to type 'string[]'.
   Type 'number' is not assignable to type 'string'.
-tests/cases/compiler/widenedTypes.ts(24,5): error TS2322: Type '{ [x: string]: number; x: number; y: null; }' is not assignable to type '{ [x: string]: string; }'.
-  Index signatures are incompatible.
+tests/cases/compiler/widenedTypes.ts(24,5): error TS2322: Type '{ x: number; y: null; }' is not assignable to type '{ [x: string]: string; }'.
+  Property 'x' is incompatible with index signature.
     Type 'number' is not assignable to type 'string'.
 
 
@@ -52,6 +52,6 @@ tests/cases/compiler/widenedTypes.ts(24,5): error TS2322: Type '{ [x: string]: n
 !!! error TS2322:   Type 'number' is not assignable to type 'string'.
     var obj: { [x: string]: string; } = { x: 3, y: null }; // assignable because null is widened, and therefore BCT is any
         ~~~
-!!! error TS2322: Type '{ [x: string]: number; x: number; y: null; }' is not assignable to type '{ [x: string]: string; }'.
-!!! error TS2322:   Index signatures are incompatible.
+!!! error TS2322: Type '{ x: number; y: null; }' is not assignable to type '{ [x: string]: string; }'.
+!!! error TS2322:   Property 'x' is incompatible with index signature.
 !!! error TS2322:     Type 'number' is not assignable to type 'string'.
\ No newline at end of file
diff --git a/tests/baselines/reference/wrappedAndRecursiveConstraints4.errors.txt b/tests/baselines/reference/wrappedAndRecursiveConstraints4.errors.txt
index 60602351b46..47e8e6ff4f2 100644
--- a/tests/baselines/reference/wrappedAndRecursiveConstraints4.errors.txt
+++ b/tests/baselines/reference/wrappedAndRecursiveConstraints4.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/types/typeParameters/typeArgumentLists/wrappedAndRecursiveConstraints4.ts(13,12): error TS2345: Argument of type '{ [x: number]: undefined; length: number; charAt: (x: number) => void; }' is not assignable to parameter of type 'string'.
+tests/cases/conformance/types/typeParameters/typeArgumentLists/wrappedAndRecursiveConstraints4.ts(13,12): error TS2345: Argument of type '{ length: number; charAt: (x: number) => void; }' is not assignable to parameter of type 'string'.
 
 
 ==== tests/cases/conformance/types/typeParameters/typeArgumentLists/wrappedAndRecursiveConstraints4.ts (1 errors) ====
@@ -16,4 +16,4 @@ tests/cases/conformance/types/typeParameters/typeArgumentLists/wrappedAndRecursi
     var r = c.foo('');
     var r2 = r({ length: 3, charAt: (x: number) => { '' } }); // error
                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '{ [x: number]: undefined; length: number; charAt: (x: number) => void; }' is not assignable to parameter of type 'string'.
\ No newline at end of file
+!!! error TS2345: Argument of type '{ length: number; charAt: (x: number) => void; }' is not assignable to parameter of type 'string'.
\ No newline at end of file
diff --git a/tests/cases/compiler/APISample_compile.ts b/tests/cases/compiler/APISample_compile.ts
index c63009f7d63..9672b9863fa 100644
--- a/tests/cases/compiler/APISample_compile.ts
+++ b/tests/cases/compiler/APISample_compile.ts
@@ -18,7 +18,7 @@ export function compile(fileNames: string[], options: ts.CompilerOptions): void
     var program = ts.createProgram(fileNames, options);
     var emitResult = program.emit();
 
-    var allDiagnostics = ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics);
+    var allDiagnostics = ts.getPreEmitDiagnostics(program);
 
     allDiagnostics.forEach(diagnostic => {
         var { line, character } = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
diff --git a/tests/cases/compiler/exportRedeclarationTypeAliases.ts b/tests/cases/compiler/exportRedeclarationTypeAliases.ts
new file mode 100644
index 00000000000..eb5cbcd4c6d
--- /dev/null
+++ b/tests/cases/compiler/exportRedeclarationTypeAliases.ts
@@ -0,0 +1,4 @@
+// @module: commonjs
+export type Foo = number;
+export function Foo(): number;
+export function Foo(): any {}
\ No newline at end of file
diff --git a/tests/cases/compiler/implicitIndexSignatures.ts b/tests/cases/compiler/implicitIndexSignatures.ts
new file mode 100644
index 00000000000..2e36a91bada
--- /dev/null
+++ b/tests/cases/compiler/implicitIndexSignatures.ts
@@ -0,0 +1,45 @@
+type StringMap = { [x: string]: string };
+
+const empty1 = {};
+let empty2: {};
+const names1 = { a: "foo", b: "bar" };
+let names2: { a: string, b: string };
+let map: StringMap;
+map = { x: "xxx", y: "yyy" };
+map = empty1;
+map = empty2;
+map = names1;
+map = names2;
+
+declare function getStringIndexValue<T>(map: { [x: string]: T }): T;
+declare function getNumberIndexValue<T>(map: { [x: number]: T }): T;
+
+function f1() {
+    const o1 = { a: 1, b: 2 };
+    let o2: { a: number, b: number };
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+}
+
+function f2() {
+    const o1 = { a: "1", b: "2" };
+    let o2: { a: string, b: string };
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+}
+
+function f3() {
+    const o1 = { a: 1, b: "2" };
+    let o2: { a: number, b: string };
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+}
+
+function f4() {
+    const o1 = { 0: "0", 1: "1", count: 2 };
+    let o2: { 0: string, 1: string, count: number };    
+    const v1 = getStringIndexValue(o1);
+    const v2 = getStringIndexValue(o2);
+    const v3 = getNumberIndexValue(o1);
+    const v4 = getNumberIndexValue(o2);
+}
diff --git a/tests/cases/compiler/jsFileCompilationDecoratorSyntax.ts b/tests/cases/compiler/jsFileCompilationDecoratorSyntax.ts
index 2ef95db01fe..6627fb5dca0 100644
--- a/tests/cases/compiler/jsFileCompilationDecoratorSyntax.ts
+++ b/tests/cases/compiler/jsFileCompilationDecoratorSyntax.ts
@@ -1,3 +1,5 @@
 // @allowJs: true
+// @noEmit: true
+// @experimentalDecorators: true
 // @filename: a.js
-@internal class C { }
\ No newline at end of file
+@internal class C { }
diff --git a/tests/cases/compiler/protectedMembers.ts b/tests/cases/compiler/protectedMembers.ts
index ae32e472425..b7528f26068 100644
--- a/tests/cases/compiler/protectedMembers.ts
+++ b/tests/cases/compiler/protectedMembers.ts
@@ -82,7 +82,6 @@ interface E extends C {
 }
 
 class CC {
-    // Error, constructor cannot be protected
     protected constructor() {
     }
 }
diff --git a/tests/cases/compiler/relativeNamesInClassicResolution.ts b/tests/cases/compiler/relativeNamesInClassicResolution.ts
new file mode 100644
index 00000000000..7c73a2e3cad
--- /dev/null
+++ b/tests/cases/compiler/relativeNamesInClassicResolution.ts
@@ -0,0 +1,7 @@
+// @module:amd
+
+// @filename: somefolder/a.ts
+import {x} from "./b"
+
+// @filename: b.ts
+export let x = 1;
\ No newline at end of file
diff --git a/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts
index c2e4855e63a..1c9a801429d 100644
--- a/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts
+++ b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility.ts
@@ -1,18 +1,20 @@
+// @declaration: true
+
 class C {
     public constructor(public x: number) { }
 }
 
 class D {
-    private constructor(public x: number) { } // error
+    private constructor(public x: number) { }
 }
 
 class E {
-    protected constructor(public x: number) { } // error
+    protected constructor(public x: number) { }
 }
 
 var c = new C(1);
-var d = new D(1);
-var e = new E(1);
+var d = new D(1); // error
+var e = new E(1); // error
 
 module Generic {
     class C<T> {
@@ -20,14 +22,14 @@ module Generic {
     }
 
     class D<T> {
-        private constructor(public x: T) { } // error
+        private constructor(public x: T) { }
     }
 
     class E<T> {
-        protected constructor(public x: T) { } // error
+        protected constructor(public x: T) { }
     }
 
     var c = new C(1);
-    var d = new D(1);
-    var e = new E(1);
+    var d = new D(1); // error
+    var e = new E(1); // error
 }
diff --git a/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts
new file mode 100644
index 00000000000..2a961e2c067
--- /dev/null
+++ b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility2.ts
@@ -0,0 +1,42 @@
+// @declaration: true
+
+class BaseA {
+    public constructor(public x: number) { }
+    createInstance() { new BaseA(1); }
+}
+
+class BaseB {
+    protected constructor(public x: number) { }
+    createInstance() { new BaseB(1); }
+}
+
+class BaseC {
+     private constructor(public x: number) { }
+     createInstance() { new BaseC(1); }
+}
+
+class DerivedA extends BaseA {
+    constructor(public x: number) { super(x); }
+    createInstance() { new DerivedA(1); }
+    createBaseInstance() { new BaseA(1); }
+}
+
+class DerivedB extends BaseB {
+    constructor(public x: number) { super(x); }
+    createInstance() { new DerivedB(1); }
+    createBaseInstance() { new BaseB(1); } // error
+}
+
+class DerivedC extends BaseC { // error
+    constructor(public x: number) { super(x); }
+    createInstance() { new DerivedC(1); }
+    createBaseInstance() { new BaseC(1); } // error
+}
+
+var ba = new BaseA(1);
+var bb = new BaseB(1); // error
+var bc = new BaseC(1); // error
+
+var da = new DerivedA(1);
+var db = new DerivedB(1);
+var dc = new DerivedC(1);
\ No newline at end of file
diff --git a/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility3.ts b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility3.ts
new file mode 100644
index 00000000000..91bb4873d96
--- /dev/null
+++ b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility3.ts
@@ -0,0 +1,35 @@
+// @declaration: true
+
+class Foo {
+     constructor(public x: number) { }
+}
+
+class Bar {
+    public constructor(public x: number) { }
+}
+
+class Baz {
+    protected constructor(public x: number) { }
+}
+
+class Qux {
+     private constructor(public x: number) { }
+}
+
+// b is public
+let a = Foo;
+a = Bar;
+a = Baz; // error Baz is protected
+a = Qux; // error Qux is private
+
+// b is protected
+let b = Baz;
+b = Foo;
+b = Bar;
+b = Qux; // error Qux is private
+
+// c is private
+let c = Qux;
+c = Foo;
+c = Bar;
+c = Baz;
\ No newline at end of file
diff --git a/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility4.ts b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility4.ts
new file mode 100644
index 00000000000..3760f2176ae
--- /dev/null
+++ b/tests/cases/conformance/classes/constructorDeclarations/classConstructorAccessibility4.ts
@@ -0,0 +1,31 @@
+// @declaration: true
+
+class A {
+    private constructor() { }
+
+    method() {
+        class B {
+            method() {
+                new A(); // OK
+            }
+        }
+
+        class C extends A { // OK
+        }
+    }
+}
+
+class D {
+    protected constructor() { }
+
+    method() {
+        class E {
+            method() {
+                new D(); // OK
+            }
+        }
+
+        class F extends D { // OK
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/classes/constructorDeclarations/classConstructorOverloadsAccessibility.ts b/tests/cases/conformance/classes/constructorDeclarations/classConstructorOverloadsAccessibility.ts
new file mode 100644
index 00000000000..5ed20d03853
--- /dev/null
+++ b/tests/cases/conformance/classes/constructorDeclarations/classConstructorOverloadsAccessibility.ts
@@ -0,0 +1,34 @@
+// @declaration: true
+
+class A {
+	public constructor(a: boolean) // error
+	protected constructor(a: number) // error
+	private constructor(a: string)
+	private constructor() { 
+		
+	}
+}
+
+class B {
+	protected constructor(a: number) // error
+	constructor(a: string)
+	constructor() { 
+		
+	}
+}
+
+class C {
+	protected constructor(a: number)
+	protected constructor(a: string)
+	protected constructor() { 
+		
+	}
+}
+
+class D {
+	constructor(a: number)
+	constructor(a: string)
+	public constructor() { 
+		
+	}
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicates01.ts b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicates01.ts
new file mode 100644
index 00000000000..c4a223f07ef
--- /dev/null
+++ b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicates01.ts
@@ -0,0 +1,6 @@
+// @declaration: true
+// @module: commonjs
+
+export function f(x: any): x is number {
+    return typeof x === "number";
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicatesWithPrivateName01.ts b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicatesWithPrivateName01.ts
new file mode 100644
index 00000000000..1398b2bc040
--- /dev/null
+++ b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitIdentifierPredicatesWithPrivateName01.ts
@@ -0,0 +1,10 @@
+// @declaration: true
+// @module: commonjs
+
+interface I {
+    a: number;
+}
+
+export function f(x: any): x is I {
+    return typeof x.a === "number";
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates01.ts b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates01.ts
new file mode 100644
index 00000000000..69af9c5b077
--- /dev/null
+++ b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates01.ts
@@ -0,0 +1,11 @@
+// @declaration: true
+// @module: commonjs
+
+export class C {
+    m(): this is D {
+        return this instanceof D;
+    }
+}
+
+export class D extends C {
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates02.ts b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates02.ts
new file mode 100644
index 00000000000..02f2a798831
--- /dev/null
+++ b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicates02.ts
@@ -0,0 +1,15 @@
+// @declaration: true
+// @module: commonjs
+
+export interface Foo {
+    a: string;
+    b: number;
+    c: boolean;
+}
+
+export const obj = {
+    m(): this is Foo {
+        let dis = this as Foo;
+        return dis.a != null && dis.b != null && dis.c != null;
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName01.ts b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName01.ts
new file mode 100644
index 00000000000..461c7d17571
--- /dev/null
+++ b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName01.ts
@@ -0,0 +1,11 @@
+// @declaration: true
+// @module: commonjs
+
+export class C {
+    m(): this is D {
+        return this instanceof D;
+    }
+}
+
+class D extends C {
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName02.ts b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName02.ts
new file mode 100644
index 00000000000..c238bb16ec8
--- /dev/null
+++ b/tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredicatesWithPrivateName02.ts
@@ -0,0 +1,15 @@
+// @declaration: true
+// @module: commonjs
+
+interface Foo {
+    a: string;
+    b: number;
+    c: boolean;
+}
+
+export const obj = {
+    m(): this is Foo {
+        let dis = this as Foo;
+        return dis.a != null && dis.b != null && dis.c != null;
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing1.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing1.ts
new file mode 100644
index 00000000000..e5d63f2e930
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing1.ts
@@ -0,0 +1,15 @@
+declare var Factory: any
+
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        super(i);
+        var s = {
+            t: this._t
+        }
+        var i = Factory.create(s);
+    }
+}
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing2.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing2.ts
new file mode 100644
index 00000000000..1b0a0d541e9
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing2.ts
@@ -0,0 +1,9 @@
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        super(() => { this._t }); // no error. only check when this is directly accessing in constructor
+    }
+}
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing3.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing3.ts
new file mode 100644
index 00000000000..1386998aaae
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing3.ts
@@ -0,0 +1,12 @@
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        let x = () => { this._t };
+        x();  // no error; we only check super is called before this when the container is a constructor
+        this._t;  // error
+        super(undefined);
+    }
+}
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing4.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing4.ts
new file mode 100644
index 00000000000..9135e03b0ce
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing4.ts
@@ -0,0 +1,15 @@
+class D extends null {
+    private _t;
+    constructor() {
+        this._t;
+        super();
+    }
+}
+
+class E extends null {
+    private _t;
+    constructor() {
+        super();
+        this._t;
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing5.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing5.ts
new file mode 100644
index 00000000000..17820277585
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing5.ts
@@ -0,0 +1,6 @@
+class D extends null {
+    private _t;
+    constructor() {
+        this._t;  // No error
+    }
+}
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing6.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing6.ts
new file mode 100644
index 00000000000..8f36f2eb056
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing6.ts
@@ -0,0 +1,9 @@
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        super(this); 
+    }
+}
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing7.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing7.ts
new file mode 100644
index 00000000000..d40c96a60f3
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing7.ts
@@ -0,0 +1,12 @@
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        let x = {
+            j: this._t,
+        }
+        super(undefined);
+    }
+}
diff --git a/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing8.ts b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing8.ts
new file mode 100644
index 00000000000..5742cdab845
--- /dev/null
+++ b/tests/cases/conformance/es6/classDeclaration/superCallBeforeThisAccessing8.ts
@@ -0,0 +1,12 @@
+class Base {
+    constructor(c) { }
+}
+class D extends Base {
+    private _t;
+    constructor() {
+        let x = {
+            k: super(undefined), 
+            j: this._t,  // no error
+        }
+    }
+}
diff --git a/tests/cases/conformance/expressions/typeGuards/typeGuardOfFormFunctionEquality.ts b/tests/cases/conformance/expressions/typeGuards/typeGuardOfFormFunctionEquality.ts
new file mode 100644
index 00000000000..baff942bb8e
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typeGuardOfFormFunctionEquality.ts
@@ -0,0 +1,14 @@
+declare function isString1(a: number, b: Object): b is string;
+
+declare function isString2(a: Object): a is string;
+
+switch (isString1(0, "")) {
+    case isString2(""):
+    default:
+}
+
+var x = isString1(0, "") === isString2("");
+
+function isString3(a: number, b: number, c: Object): c is string {
+    return isString1(0, c);
+}
diff --git a/tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration01.ts b/tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration01.ts
new file mode 100644
index 00000000000..a445e18ee40
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration01.ts
@@ -0,0 +1,3 @@
+// @declaration: true
+
+var x: this is string;
\ No newline at end of file
diff --git a/tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts b/tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts
new file mode 100644
index 00000000000..4b010287337
--- /dev/null
+++ b/tests/cases/conformance/expressions/typeGuards/typePredicateOnVariableDeclaration02.ts
@@ -0,0 +1,3 @@
+// @declaration: true
+
+var y: z is number;
\ No newline at end of file
diff --git a/tests/cases/conformance/types/members/typesWithPrivateConstructor.ts b/tests/cases/conformance/types/members/typesWithPrivateConstructor.ts
index 4fb24ca58e4..321864e1751 100644
--- a/tests/cases/conformance/types/members/typesWithPrivateConstructor.ts
+++ b/tests/cases/conformance/types/members/typesWithPrivateConstructor.ts
@@ -1,10 +1,10 @@
-// private constructors are not allowed
+// @declaration: true
 
 class C {
     private constructor() { }
 }
 
-var c = new C();
+var c = new C(); // error C is private
 var r: () => void = c.constructor;
 
 class C2 {
@@ -12,5 +12,5 @@ class C2 {
     private constructor(x: any) { }
 }
 
-var c2 = new C2();
+var c2 = new C2(); // error C2 is private
 var r2: (x: number) => void = c2.constructor;
\ No newline at end of file
diff --git a/tests/cases/conformance/types/members/typesWithProtectedConstructor.ts b/tests/cases/conformance/types/members/typesWithProtectedConstructor.ts
new file mode 100644
index 00000000000..e7f6adc38a8
--- /dev/null
+++ b/tests/cases/conformance/types/members/typesWithProtectedConstructor.ts
@@ -0,0 +1,16 @@
+// @declaration: true
+
+class C {
+    protected constructor() { }
+}
+
+var c = new C(); // error C is protected
+var r: () => void = c.constructor;
+
+class C2 {
+    protected constructor(x: number);
+    protected constructor(x: any) { }
+}
+
+var c2 = new C2(); // error C2 is protected
+var r2: (x: number) => void = c2.constructor;
\ No newline at end of file
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts b/tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts
index b71677554a2..8a7120acbb3 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts
+++ b/tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts
@@ -1,15 +1,8 @@
 /// <reference path="fourslash.ts" />
 
 // @allowJs: true
+// @experimentalDecorators: true
 // @Filename: a.js
 //// @internal class C {}
 
-verify.getSemanticDiagnostics(`[
-  {
-    "message": "'decorators' can only be used in a .ts file.",
-    "start": 0,
-    "length": 9,
-    "category": "error",
-    "code": 8017
-  }
-]`);
\ No newline at end of file
+verify.getSemanticDiagnostics(`[]`);
diff --git a/tests/cases/fourslash/quickInfoOnPrivateConstructorCall.ts b/tests/cases/fourslash/quickInfoOnPrivateConstructorCall.ts
new file mode 100644
index 00000000000..5ebdcd815b2
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoOnPrivateConstructorCall.ts
@@ -0,0 +1,9 @@
+/// <reference path='fourslash.ts' />
+
+////class A {
+////    private constructor() {}
+////}
+////var x = new A(/*1*/
+
+goTo.marker("1");
+verify.not.signatureHelpPresent();
\ No newline at end of file
diff --git a/tests/cases/fourslash/quickInfoOnProtectedConstructorCall.ts b/tests/cases/fourslash/quickInfoOnProtectedConstructorCall.ts
new file mode 100644
index 00000000000..094a07f3d51
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoOnProtectedConstructorCall.ts
@@ -0,0 +1,9 @@
+/// <reference path='fourslash.ts' />
+
+////class A {
+////    protected constructor() {}
+////}
+////var x = new A(/*1*/
+
+goTo.marker("1");
+verify.not.signatureHelpPresent();
\ No newline at end of file
diff --git a/tests/cases/fourslash/thisPredicateFunctionCompletions01.ts b/tests/cases/fourslash/thisPredicateFunctionCompletions01.ts
new file mode 100644
index 00000000000..8c9abb85418
--- /dev/null
+++ b/tests/cases/fourslash/thisPredicateFunctionCompletions01.ts
@@ -0,0 +1,52 @@
+/// <reference path="fourslash.ts" />
+
+//// class FileSystemObject {
+////     isFile(): this is Item {
+////         return this instanceof Item;
+////     }
+////     isDirectory(): this is Directory {
+////         return this instanceof Directory;
+////     }
+////     isNetworked(): this is (Networked & this) {
+////        return !!(this as Networked).host;
+////     }
+////     constructor(public path: string) {}
+//// }
+////
+//// class Item extends FileSystemObject {
+////     constructor(path: string, public content: string) { super(path); }
+//// }
+//// class Directory extends FileSystemObject {
+////     children: FileSystemObject[];
+//// }
+//// interface Networked {
+////     host: string;
+//// }
+////
+//// const obj: FileSystemObject = new Item("/foo", "");
+//// if (obj.isFile()) {
+////     obj./*1*/;
+////     if (obj.isNetworked()) {
+////         obj./*2*/;
+////     }
+//// }
+//// if (obj.isDirectory()) {
+////     obj./*3*/;
+////     if (obj.isNetworked()) {
+////         obj./*4*/;
+////     }
+//// }
+//// if (obj.isNetworked()) {
+////     obj./*5*/;
+//// }
+
+goTo.marker("1");
+verify.completionListContains("content");
+goTo.marker("2");
+verify.completionListContains("host");
+goTo.marker("3");
+verify.completionListContains("children");
+goTo.marker("4");
+verify.completionListContains("host");
+goTo.marker("5");
+verify.completionListContains("host");
\ No newline at end of file
diff --git a/tests/cases/fourslash/thisPredicateFunctionCompletions02.ts b/tests/cases/fourslash/thisPredicateFunctionCompletions02.ts
new file mode 100644
index 00000000000..e2e311ea649
--- /dev/null
+++ b/tests/cases/fourslash/thisPredicateFunctionCompletions02.ts
@@ -0,0 +1,43 @@
+/// <reference path="fourslash.ts" />
+
+//// interface Sundries {
+////     broken: boolean;
+//// }
+////
+//// interface Supplies {
+////     spoiled: boolean;
+//// }
+////
+//// interface Crate<T> {
+////     contents: T;
+////     isSundries(): this is Crate<Sundries>;
+////     isSupplies(): this is Crate<Supplies>;
+////     isPackedTight(): this is (this & {extraContents: T});
+//// }
+//// const crate: Crate<any>;
+//// if (crate.isPackedTight()) {
+////     crate./*1*/;
+//// }
+//// if (crate.isSundries()) {
+////     crate.contents./*2*/;
+////     if (crate.isPackedTight()) {
+////         crate./*3*/;
+////     }
+//// }
+//// if (crate.isSupplies()) {
+////     crate.contents./*4*/;
+////     if (crate.isPackedTight()) {
+////         crate./*5*/;
+////     }
+//// }
+
+goTo.marker("1");
+verify.completionListContains("extraContents");
+goTo.marker("2");
+verify.completionListContains("broken");
+goTo.marker("3");
+verify.completionListContains("extraContents");
+goTo.marker("4");
+verify.completionListContains("spoiled");
+goTo.marker("5");
+verify.completionListContains("extraContents");
\ No newline at end of file
diff --git a/tests/cases/fourslash/thisPredicateFunctionCompletions.ts b/tests/cases/fourslash/thisPredicateFunctionCompletions03.ts
similarity index 100%
rename from tests/cases/fourslash/thisPredicateFunctionCompletions.ts
rename to tests/cases/fourslash/thisPredicateFunctionCompletions03.ts
diff --git a/tests/cases/fourslash/thisPredicateFunctionQuickInfo01.ts b/tests/cases/fourslash/thisPredicateFunctionQuickInfo01.ts
new file mode 100644
index 00000000000..135df559189
--- /dev/null
+++ b/tests/cases/fourslash/thisPredicateFunctionQuickInfo01.ts
@@ -0,0 +1,59 @@
+/// <reference path="fourslash.ts" />
+
+//// class FileSystemObject {
+////     /*1*/isFile(): this is Item {
+////         return this instanceof Item;
+////     }
+////     /*2*/isDirectory(): this is Directory {
+////         return this instanceof Directory;
+////     }
+////     /*3*/isNetworked(): this is (Networked & this) {
+////        return !!(this as Networked).host;
+////     }
+////     constructor(public path: string) {}
+//// }
+////
+//// class Item extends FileSystemObject {
+////     constructor(path: string, public content: string) { super(path); }
+//// }
+//// class Directory extends FileSystemObject {
+////     children: FileSystemObject[];
+//// }
+//// interface Networked {
+////     host: string;
+//// }
+////
+//// const obj: FileSystemObject = new Item("/foo", "");
+//// if (obj.isFile/*4*/()) {
+////     obj.;
+////     if (obj.isNetworked/*5*/()) {
+////         obj.;
+////     }
+//// }
+//// if (obj.isDirectory/*6*/()) {
+////     obj.;
+////     if (obj.isNetworked/*7*/()) {
+////         obj.;
+////     }
+//// }
+//// if (obj.isNetworked/*8*/()) {
+////     obj.;
+//// }
+
+goTo.marker("1");
+verify.quickInfoIs("(method) FileSystemObject.isFile(): this is Item");
+goTo.marker("2");
+verify.quickInfoIs("(method) FileSystemObject.isDirectory(): this is Directory");
+goTo.marker("3");
+verify.quickInfoIs("(method) FileSystemObject.isNetworked(): this is Networked & this");
+
+goTo.marker("4");
+verify.quickInfoIs("(method) FileSystemObject.isFile(): this is Item");
+goTo.marker("5");
+verify.quickInfoIs("(method) FileSystemObject.isNetworked(): this is Networked & Item");
+goTo.marker("6");
+verify.quickInfoIs("(method) FileSystemObject.isDirectory(): this is Directory");
+goTo.marker("7");
+verify.quickInfoIs("(method) FileSystemObject.isNetworked(): this is Networked & Directory");
+goTo.marker("8");
+verify.quickInfoIs("(method) FileSystemObject.isNetworked(): this is Networked & FileSystemObject");
\ No newline at end of file
diff --git a/tests/cases/fourslash/thisPredicateFunctionQuickInfo02.ts b/tests/cases/fourslash/thisPredicateFunctionQuickInfo02.ts
new file mode 100644
index 00000000000..b8135026c82
--- /dev/null
+++ b/tests/cases/fourslash/thisPredicateFunctionQuickInfo02.ts
@@ -0,0 +1,57 @@
+/// <reference path="fourslash.ts" />
+
+//// interface Sundries {
+////     broken: boolean;
+//// }
+////
+//// interface Supplies {
+////     spoiled: boolean;
+//// }
+////
+//// interface Crate<T> {
+////     contents: T;
+////     /*1*/isSundries(): this is Crate<Sundries>;
+////     /*2*/isSupplies(): this is Crate<Supplies>;
+////     /*3*/isPackedTight(): this is (this & {extraContents: T});
+//// }
+//// const crate: Crate<any>;
+//// if (crate.isPackedTight/*4*/()) {
+////     crate.;
+//// }
+//// if (crate.isSundries/*5*/()) {
+////     crate.contents.;
+////     if (crate.isPackedTight/*6*/()) {
+////        crate.;
+////     }
+//// }
+//// if (crate.isSupplies/*7*/()) {
+////     crate.contents.;
+////     if (crate.isPackedTight/*8*/()) {
+////        crate.;
+////     }
+//// }
+
+goTo.marker("1");
+verify.quickInfoIs("(method) Crate<T>.isSundries(): this is Crate<Sundries>");
+goTo.marker("2");
+verify.quickInfoIs("(method) Crate<T>.isSupplies(): this is Crate<Supplies>");
+goTo.marker("3");
+verify.quickInfoIs(`(method) Crate<T>.isPackedTight(): this is this & {
+    extraContents: T;
+}`);
+goTo.marker("4");
+verify.quickInfoIs(`(method) Crate<any>.isPackedTight(): this is Crate<any> & {
+    extraContents: any;
+}`);
+goTo.marker("5");
+verify.quickInfoIs("(method) Crate<any>.isSundries(): this is Crate<Sundries>");
+goTo.marker("6");
+verify.quickInfoIs(`(method) Crate<Sundries>.isPackedTight(): this is Crate<Sundries> & {
+    extraContents: Sundries;
+}`);
+goTo.marker("7");
+verify.quickInfoIs("(method) Crate<any>.isSupplies(): this is Crate<Supplies>");
+goTo.marker("8");
+verify.quickInfoIs(`(method) Crate<Supplies>.isPackedTight(): this is Crate<Supplies> & {
+    extraContents: Supplies;
+}`);
\ No newline at end of file
diff --git a/tests/cases/fourslash/thisPredicateMemberCompletions.ts b/tests/cases/fourslash/thisPredicateMemberCompletions.ts
deleted file mode 100644
index 24ce742faac..00000000000
--- a/tests/cases/fourslash/thisPredicateMemberCompletions.ts
+++ /dev/null
@@ -1,95 +0,0 @@
-/// <reference path="fourslash.ts" />
-
-//// class FileSystemObject {
-////     get is/*1*/File(): this is Item {
-////         return this instanceof Item;
-////     }
-////     set is/*2*/File(param) {
-////         // noop
-////     }
-////     get is/*3*/Directory(): this is Directory {
-////         return this instanceof Directory;
-////     }
-////     is/*4*/Networked: this is (Networked & this);
-////     constructor(public path: string) {}
-//// }
-////
-//// class Item extends FileSystemObject {
-////     constructor(path: string, public content: string) { super(path); }
-//// }
-//// class Directory extends FileSystemObject {
-////     children: FileSystemObject[];
-//// }
-//// interface Networked {
-////     host: string;
-//// }
-////
-//// interface Sundries {
-////     broken: boolean;
-//// }
-////
-//// interface Supplies {
-////     spoiled: boolean;
-//// }
-////
-//// interface Crate<T> {
-////     contents: T;
-////     is/*5*/Sundries: this is Crate<Sundries>;
-////     is/*6*/Supplies: this is Crate<Supplies>;
-////     is/*7*/PackedTight: this is (this & {extraContents: T});
-//// }
-////
-//// const obj: FileSystemObject = new Item("/foo", "");
-//// if (obj.is/*8*/File) {
-////     obj./*9*/;
-////     if (obj.is/*10*/Networked) {
-////         obj./*11*/;
-////     }
-//// }
-//// if (obj.is/*12*/Directory) {
-////     obj./*13*/;
-////     if (obj.is/*14*/Networked) {
-////         obj./*15*/;
-////     }
-//// }
-//// if (obj.is/*16*/Networked) {
-////     obj./*17*/;
-//// }
-////
-//// const crate: Crate<any>;
-//// if (crate.is/*18*/PackedTight) {
-////     crate./*19*/;
-//// }
-//// if (crate.is/*20*/Sundries) {
-////     crate.contents./*21*/;
-////     if (crate.is/*22*/PackedTight) {
-////         crate./*23*/
-////     }
-//// }
-//// if (crate.is/*24*/Supplies) {
-////     crate.contents./*25*/;
-////     if (crate.is/*26*/PackedTight) {
-////         crate./*27*/
-////     }
-//// }
-
-goTo.marker("9");
-verify.completionListContains("content");
-goTo.marker("11");
-verify.completionListContains("host");
-goTo.marker("13");
-verify.completionListContains("children");
-goTo.marker("15");
-verify.completionListContains("host");
-goTo.marker("17");
-verify.completionListContains("host");
-goTo.marker("19");
-verify.completionListContains("extraContents");
-goTo.marker("21");
-verify.completionListContains("broken");
-goTo.marker("23");
-verify.completionListContains("extraContents");
-goTo.marker("25");
-verify.completionListContains("spoiled");
-goTo.marker("27");
-verify.completionListContains("extraContents");
\ No newline at end of file
diff --git a/tests/cases/fourslash/thisPredicateMemberQuickInfo.ts b/tests/cases/fourslash/thisPredicateMemberQuickInfo.ts
deleted file mode 100644
index 20d519e0008..00000000000
--- a/tests/cases/fourslash/thisPredicateMemberQuickInfo.ts
+++ /dev/null
@@ -1,117 +0,0 @@
-/// <reference path="fourslash.ts" />
-
-//// class FileSystemObject {
-////     get is/*1*/File(): this is Item {
-////         return this instanceof Item;
-////     }
-////     set is/*2*/File(param) {
-////         // noop
-////     }
-////     get is/*3*/Directory(): this is Directory {
-////         return this instanceof Directory;
-////     }
-////     is/*4*/Networked: this is (Networked & this);
-////     constructor(public path: string) {}
-//// }
-////
-//// class Item extends FileSystemObject {
-////     constructor(path: string, public content: string) { super(path); }
-//// }
-//// class Directory extends FileSystemObject {
-////     children: FileSystemObject[];
-//// }
-//// interface Networked {
-////     host: string;
-//// }
-////
-//// interface Sundries {
-////     broken: boolean;
-//// }
-////
-//// interface Supplies {
-////     spoiled: boolean;
-//// }
-////
-//// interface Crate<T> {
-////     contents: T;
-////     is/*5*/Sundries: this is Crate<Sundries>;
-////     is/*6*/Supplies: this is Crate<Supplies>;
-////     is/*7*/PackedTight: this is (this & {extraContents: T});
-//// }
-////
-//// const obj: FileSystemObject = new Item("/foo", "");
-//// if (obj.is/*8*/File) {
-////     obj./*9*/;
-////     if (obj.is/*10*/Networked) {
-////         obj./*11*/;
-////     }
-//// }
-//// if (obj.is/*12*/Directory) {
-////     obj./*13*/;
-////     if (obj.is/*14*/Networked) {
-////         obj./*15*/;
-////     }
-//// }
-//// if (obj.is/*16*/Networked) {
-////     obj./*17*/;
-//// }
-////
-//// const crate: Crate<any>;
-//// if (crate.is/*18*/PackedTight) {
-////     crate./*19*/;
-//// }
-//// if (crate.is/*20*/Sundries) {
-////     crate.contents./*21*/;
-////     if (crate.is/*22*/PackedTight) {
-////         crate./*23*/
-////     }
-//// }
-//// if (crate.is/*24*/Supplies) {
-////     crate.contents./*25*/;
-////     if (crate.is/*26*/PackedTight) {
-////         crate./*27*/
-////     }
-//// }
-
-goTo.marker("1");
-verify.quickInfoIs("(property) FileSystemObject.isFile: this is Item");
-goTo.marker("2");
-verify.quickInfoIs("(property) FileSystemObject.isFile: this is Item");
-goTo.marker("3");
-verify.quickInfoIs("(property) FileSystemObject.isDirectory: this is Directory");
-goTo.marker("4");
-verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & this");
-goTo.marker("5");
-verify.quickInfoIs("(property) Crate<T>.isSundries: this is Crate<Sundries>");
-goTo.marker("6");
-verify.quickInfoIs("(property) Crate<T>.isSupplies: this is Crate<Supplies>");
-goTo.marker("7");
-verify.quickInfoIs(`(property) Crate<T>.isPackedTight: this is this & {
-    extraContents: T;
-}`);
-goTo.marker("8");
-verify.quickInfoIs("(property) FileSystemObject.isFile: this is Item");
-goTo.marker("10");
-verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & Item");
-goTo.marker("12");
-verify.quickInfoIs("(property) FileSystemObject.isDirectory: this is Directory");
-goTo.marker("14");
-verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & Directory");
-goTo.marker("16");
-verify.quickInfoIs("(property) FileSystemObject.isNetworked: this is Networked & FileSystemObject");
-goTo.marker("18");
-verify.quickInfoIs(`(property) Crate<any>.isPackedTight: this is Crate<any> & {
-    extraContents: any;
-}`);
-goTo.marker("20");
-verify.quickInfoIs("(property) Crate<any>.isSundries: this is Crate<Sundries>");
-goTo.marker("22");
-verify.quickInfoIs(`(property) Crate<Sundries>.isPackedTight: this is Crate<Sundries> & {
-    extraContents: Sundries;
-}`);
-goTo.marker("24");
-verify.quickInfoIs("(property) Crate<any>.isSupplies: this is Crate<Supplies>");
-goTo.marker("26");
-verify.quickInfoIs(`(property) Crate<Supplies>.isPackedTight: this is Crate<Supplies> & {
-    extraContents: Supplies;
-}`);
\ No newline at end of file
diff --git a/tests/cases/unittests/moduleResolution.ts b/tests/cases/unittests/moduleResolution.ts
index 1173f579f2c..9a52d9896e4 100644
--- a/tests/cases/unittests/moduleResolution.ts
+++ b/tests/cases/unittests/moduleResolution.ts
@@ -48,7 +48,7 @@ module ts {
                     return hasProperty(directories, path); 
                 },
                 fileExists: path => {
-                    assert.isTrue(hasProperty(directories, getDirectoryPath(path)), "'fileExists' request in non-existing directory");
+                    assert.isTrue(hasProperty(directories, getDirectoryPath(path)), `'fileExists' '${path}' request in non-existing directory`);
                     return hasProperty(map, path);
                 }
             }
@@ -814,7 +814,6 @@ import b = require("./moduleB.ts");
 
         it ("classic + rootDirs", () => {
             test(/*hasDirectoryExists*/ false);
-            test(/*hasDirectoryExists*/ true);
 
             function test(hasDirectoryExists: boolean) {
                 let file1: File = { name: "/root/folder1/file1.ts" };
@@ -844,24 +843,20 @@ import b = require("./moduleB.ts");
                     "/root/generated/folder1/file1.d.ts",
                     // then try alternative rootDir entry
                 ]);
-                check("../folder1/file1_1", file3, file4, [
-                    // load from initial location
+                check("folder1/file1_1", file3, file4, [
+                    // current location
+                    "/root/generated/folder2/folder1/file1_1.ts",
+                    "/root/generated/folder2/folder1/file1_1.tsx",
+                    "/root/generated/folder2/folder1/file1_1.d.ts",
+                    // other entry in rootDirs
                     "/root/generated/folder1/file1_1.ts",
                     "/root/generated/folder1/file1_1.tsx",
                     "/root/generated/folder1/file1_1.d.ts",
-                    // load from alternative rootDir entry
-                    "/root/folder1/file1_1.ts",
-                    "/root/folder1/file1_1.tsx",
-                    "/root/folder1/file1_1.d.ts",
-                    // fallback to classic
-                    // step1: initial location 
-                    "/root/generated/folder1/file1_1.ts",
-                    "/root/generated/folder1/file1_1.tsx",
-                    "/root/generated/folder1/file1_1.d.ts",
-                    // step2: walk 1 level up
+                    // fallback
                     "/root/folder1/file1_1.ts",
                     "/root/folder1/file1_1.tsx",
                     "/root/folder1/file1_1.d.ts",
+                    // found one
                 ]);
 
                 function check(name: string, container: File, expected: File, expectedFailedLookups: string[]) {