diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5cd71544272..29f31342850 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1307,6 +1307,17 @@ module ts {
                     buildSymbolDisplay(type.symbol, writer, enclosingDeclaration, SymbolFlags.Value);
                 }
 
+                function getIndexerParameterName(type: ObjectType, indexKind: IndexKind, fallbackName: string): string {
+                    var declaration = <SignatureDeclaration>getIndexDeclarationOfSymbol(type.symbol, indexKind);
+                    if (!declaration) {
+                        // declaration might not be found if indexer was added from the contextual type.
+                        // in this case use fallback name
+                        return fallbackName;
+                    }
+                    Debug.assert(declaration.parameters.length !== 0);
+                    return declarationNameToString(declaration.parameters[0].name);
+                }
+
                 function writeLiteralType(type: ObjectType, flags: TypeFormatFlags) {
                     var resolved = resolveObjectOrUnionTypeMembers(type);
                     if (!resolved.properties.length && !resolved.stringIndexType && !resolved.numberIndexType) {
@@ -1359,7 +1370,8 @@ module ts {
                     if (resolved.stringIndexType) {
                         // [x: string]: 
                         writePunctuation(writer, SyntaxKind.OpenBracketToken);
-                        writer.writeParameter("x");
+                        resolved.symbol
+                        writer.writeParameter(getIndexerParameterName(resolved, IndexKind.String, /*fallbackName*/"x"));
                         writePunctuation(writer, SyntaxKind.ColonToken);
                         writeSpace(writer);
                         writeKeyword(writer, SyntaxKind.StringKeyword);
@@ -1373,7 +1385,7 @@ module ts {
                     if (resolved.numberIndexType) {
                         // [x: number]: 
                         writePunctuation(writer, SyntaxKind.OpenBracketToken);
-                        writer.writeParameter("x");
+                        writer.writeParameter(getIndexerParameterName(resolved, IndexKind.Number, /*fallbackName*/"x"));
                         writePunctuation(writer, SyntaxKind.ColonToken);
                         writeSpace(writer);
                         writeKeyword(writer, SyntaxKind.NumberKeyword);
diff --git a/tests/baselines/reference/arrayLiteralContextualType.types b/tests/baselines/reference/arrayLiteralContextualType.types
index 5797999b7df..b6d8377d012 100644
--- a/tests/baselines/reference/arrayLiteralContextualType.types
+++ b/tests/baselines/reference/arrayLiteralContextualType.types
@@ -32,8 +32,8 @@ function foo(animals: IAnimal[]) { }
 >IAnimal : IAnimal
 
 function bar(animals: { [n: number]: IAnimal }) { }
->bar : (animals: { [x: number]: IAnimal; }) => void
->animals : { [x: number]: IAnimal; }
+>bar : (animals: { [n: number]: IAnimal; }) => void
+>animals : { [n: number]: IAnimal; }
 >n : number
 >IAnimal : IAnimal
 
@@ -53,7 +53,7 @@ foo([
 ]); // Legal because of the contextual type IAnimal provided by the parameter
 bar([
 >bar([    new Giraffe(),    new Elephant()]) : void
->bar : (animals: { [x: number]: IAnimal; }) => void
+>bar : (animals: { [n: number]: IAnimal; }) => void
 >[    new Giraffe(),    new Elephant()] : (Giraffe | Elephant)[]
 
     new Giraffe(),
@@ -81,6 +81,6 @@ foo(arr); // ok because arr is Array<Giraffe|Elephant> not {}[]
 
 bar(arr); // ok because arr is Array<Giraffe|Elephant> not {}[]
 >bar(arr) : void
->bar : (animals: { [x: number]: IAnimal; }) => void
+>bar : (animals: { [n: number]: IAnimal; }) => void
 >arr : (Giraffe | Elephant)[]
 
diff --git a/tests/baselines/reference/arrayLiterals.types b/tests/baselines/reference/arrayLiterals.types
index 62475fa2b4a..b22543d3edf 100644
--- a/tests/baselines/reference/arrayLiterals.types
+++ b/tests/baselines/reference/arrayLiterals.types
@@ -61,7 +61,7 @@ var classTypeArray: Array<typeof C>; // Should OK, not be a parse error
 
 // Contextual type C with numeric index signature makes array literal of EveryType E of type BCT(E,C)[]
 var context1: { [n: number]: { a: string; b: number; }; } = [{ a: '', b: 0, c: '' }, { a: "", b: 3, c: 0 }];
->context1 : { [x: number]: { a: string; b: number; }; }
+>context1 : { [n: number]: { a: string; b: number; }; }
 >n : number
 >a : string
 >b : number
diff --git a/tests/baselines/reference/assignmentCompat1.errors.txt b/tests/baselines/reference/assignmentCompat1.errors.txt
index 57ce797f5b2..6734e6fc964 100644
--- a/tests/baselines/reference/assignmentCompat1.errors.txt
+++ b/tests/baselines/reference/assignmentCompat1.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/compiler/assignmentCompat1.ts(4,1): error TS2322: Type '{ [x: string]: any; }' is not assignable to type '{ one: number; }'.
-  Property 'one' is missing in type '{ [x: string]: any; }'.
-tests/cases/compiler/assignmentCompat1.ts(5,1): error TS2322: Type '{ one: number; }' is not assignable to type '{ [x: string]: any; }'.
+tests/cases/compiler/assignmentCompat1.ts(4,1): error TS2322: Type '{ [index: string]: any; }' is not assignable to type '{ one: number; }'.
+  Property 'one' is missing in type '{ [index: string]: any; }'.
+tests/cases/compiler/assignmentCompat1.ts(5,1): error TS2322: Type '{ one: number; }' is not assignable to type '{ [index: string]: any; }'.
   Index signature is missing in type '{ one: number; }'.
 
 
@@ -10,9 +10,9 @@ tests/cases/compiler/assignmentCompat1.ts(5,1): error TS2322: Type '{ one: numbe
     
     x = y;
     ~
-!!! error TS2322: Type '{ [x: string]: any; }' is not assignable to type '{ one: number; }'.
-!!! error TS2322:   Property 'one' is missing in type '{ [x: string]: any; }'.
+!!! error TS2322: Type '{ [index: string]: any; }' is not assignable to type '{ one: number; }'.
+!!! error TS2322:   Property 'one' is missing in type '{ [index: string]: any; }'.
     y = x;
     ~
-!!! error TS2322: Type '{ one: number; }' is not assignable to type '{ [x: string]: any; }'.
+!!! error TS2322: Type '{ one: number; }' is not assignable to type '{ [index: string]: any; }'.
 !!! error TS2322:   Index signature is missing in type '{ one: number; }'.
\ No newline at end of file
diff --git a/tests/baselines/reference/assignmentCompatability35.errors.txt b/tests/baselines/reference/assignmentCompatability35.errors.txt
index faad78c10fc..2073b861f52 100644
--- a/tests/baselines/reference/assignmentCompatability35.errors.txt
+++ b/tests/baselines/reference/assignmentCompatability35.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/assignmentCompatability35.ts(9,1): error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [x: number]: number; }'.
+tests/cases/compiler/assignmentCompatability35.ts(9,1): error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [index: number]: number; }'.
   Index signature is missing in type 'interfaceWithPublicAndOptional<number, string>'.
 
 
@@ -13,5 +13,5 @@ tests/cases/compiler/assignmentCompatability35.ts(9,1): error TS2322: Type 'inte
     }
     __test2__.__val__aa = __test1__.__val__obj4
     ~~~~~~~~~~~~~~~~~~~
-!!! error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [x: number]: number; }'.
+!!! error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [index: number]: number; }'.
 !!! error TS2322:   Index signature is missing in type 'interfaceWithPublicAndOptional<number, string>'.
\ No newline at end of file
diff --git a/tests/baselines/reference/assignmentCompatability36.errors.txt b/tests/baselines/reference/assignmentCompatability36.errors.txt
index d8c43a3f363..591dc072fab 100644
--- a/tests/baselines/reference/assignmentCompatability36.errors.txt
+++ b/tests/baselines/reference/assignmentCompatability36.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/assignmentCompatability36.ts(9,1): error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [x: string]: any; }'.
+tests/cases/compiler/assignmentCompatability36.ts(9,1): error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [index: string]: any; }'.
   Index signature is missing in type 'interfaceWithPublicAndOptional<number, string>'.
 
 
@@ -13,5 +13,5 @@ tests/cases/compiler/assignmentCompatability36.ts(9,1): error TS2322: Type 'inte
     }
     __test2__.__val__aa = __test1__.__val__obj4
     ~~~~~~~~~~~~~~~~~~~
-!!! error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [x: string]: any; }'.
+!!! error TS2322: Type 'interfaceWithPublicAndOptional<number, string>' is not assignable to type '{ [index: string]: any; }'.
 !!! error TS2322:   Index signature is missing in type 'interfaceWithPublicAndOptional<number, string>'.
\ No newline at end of file
diff --git a/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt b/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt
index a951a2b1a66..eb5020e97f9 100644
--- a/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt
+++ b/tests/baselines/reference/augmentedTypeAssignmentCompatIndexSignature.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/conformance/types/members/augmentedTypeAssignmentCompatIndexSignature.ts(15,5): error TS2322: Type '{}' is not assignable to type '{ [x: number]: Foo; }'.
+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 '{ [x: number]: Bar; }'.
+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'.
 
 
@@ -21,14 +21,14 @@ tests/cases/conformance/types/members/augmentedTypeAssignmentCompatIndexSignatur
     
     var v1: {
         ~~
-!!! error TS2322: Type '{}' is not assignable to type '{ [x: number]: Foo; }'.
+!!! 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
     
     var v2: {
         ~~
-!!! error TS2322: Type '() => void' is not assignable to type '{ [x: number]: Bar; }'.
+!!! error TS2322: Type '() => void' is not assignable to type '{ [n: number]: Bar; }'.
 !!! error TS2322:   Index signature is missing in type '() => void'.
         [n: number]: Bar
     } = f; // Should be allowed
\ No newline at end of file
diff --git a/tests/baselines/reference/badOverloadError.types b/tests/baselines/reference/badOverloadError.types
index ba9d6e76c1c..b8ae583a73c 100644
--- a/tests/baselines/reference/badOverloadError.types
+++ b/tests/baselines/reference/badOverloadError.types
@@ -3,8 +3,8 @@ function method() {
 >method : () => void
 
     var dictionary = <{ [index: string]: string; }>{};
->dictionary : { [x: string]: string; }
-><{ [index: string]: string; }>{} : { [x: string]: string; }
+>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 937339d8cbf..606cbae9231 100644
--- a/tests/baselines/reference/bestCommonTypeWithContextualTyping.types
+++ b/tests/baselines/reference/bestCommonTypeWithContextualTyping.types
@@ -33,7 +33,7 @@ var arr: Contextual[] = [e]; // Ellement[]
 >e : Ellement
 
 var obj: { [s: string]: Contextual } = { s: e }; // { s: Ellement; [s: string]: Ellement }
->obj : { [x: string]: Contextual; }
+>obj : { [s: string]: Contextual; }
 >s : string
 >Contextual : Contextual
 >{ s: e } : { [x: string]: Ellement; s: Ellement; }
diff --git a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt
index 5bb7772e75f..fe608b14379 100644
--- a/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt
+++ b/tests/baselines/reference/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.errors.txt
@@ -1,67 +1,67 @@
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(26,12): error TS2365: Operator '<' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(27,12): error TS2365: Operator '<' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(28,12): error TS2365: Operator '<' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(29,12): error TS2365: Operator '<' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(31,12): error TS2365: Operator '<' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(32,12): error TS2365: Operator '<' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(33,12): error TS2365: Operator '<' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(34,12): error TS2365: Operator '<' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(37,12): error TS2365: Operator '>' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(38,12): error TS2365: Operator '>' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(39,12): error TS2365: Operator '>' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(40,12): error TS2365: Operator '>' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(42,12): error TS2365: Operator '>' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(43,12): error TS2365: Operator '>' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(44,12): error TS2365: Operator '>' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(45,12): error TS2365: Operator '>' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(48,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(49,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(50,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(51,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(53,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(54,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(55,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(56,12): error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(59,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(60,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(61,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(62,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(64,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(65,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(66,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(67,12): error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(70,12): error TS2365: Operator '==' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(71,12): error TS2365: Operator '==' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(72,12): error TS2365: Operator '==' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(73,12): error TS2365: Operator '==' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(75,12): error TS2365: Operator '==' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(76,12): error TS2365: Operator '==' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(77,12): error TS2365: Operator '==' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(78,12): error TS2365: Operator '==' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(81,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(82,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(83,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(84,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(86,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(87,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(88,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(89,12): error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(92,12): error TS2365: Operator '===' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(93,12): error TS2365: Operator '===' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(94,12): error TS2365: Operator '===' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(95,12): error TS2365: Operator '===' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(97,12): error TS2365: Operator '===' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(98,12): error TS2365: Operator '===' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(99,12): error TS2365: Operator '===' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(100,12): error TS2365: Operator '===' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(103,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(104,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(105,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(106,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(108,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(109,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(110,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
-tests/cases/conformance/expressions/binaryOperators/comparisonOperator/comparisonOperatorWithNoRelationshipObjectsOnIndexSignature.ts(111,12): error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+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) ====
@@ -92,215 +92,215 @@ tests/cases/conformance/expressions/binaryOperators/comparisonOperator/compariso
     // operator <
     var r1a1 = a1 < b1;
                ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '<' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r1a2 = a2 < b2;
                ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '<' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r1a3 = a3 < b3;
                ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '<' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r1b1 = b1 < a1;
                ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '<' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r1b2 = b2 < a2;
                ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '<' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r1b3 = b3 < a3;
                ~~~~~~~
-!!! error TS2365: Operator '<' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+!!! error TS2365: Operator '<' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator >
     var r2a1 = a1 > b1;
                ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '>' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r2a2 = a2 > b2;
                ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '>' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r2a3 = a3 > b3;
                ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '>' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r2b1 = b1 > a1;
                ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '>' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r2b2 = b2 > a2;
                ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '>' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r2b3 = b3 > a3;
                ~~~~~~~
-!!! error TS2365: Operator '>' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+!!! error TS2365: Operator '>' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator <=
     var r3a1 = a1 <= b1;
                ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '<=' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r3a2 = a2 <= b2;
                ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '<=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r3a3 = a3 <= b3;
                ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '<=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r3b1 = b1 <= a1;
                ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '<=' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r3b2 = b2 <= a2;
                ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '<=' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r3b3 = b3 <= a3;
                ~~~~~~~~
-!!! error TS2365: Operator '<=' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+!!! error TS2365: Operator '<=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator >=
     var r4a1 = a1 >= b1;
                ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '>=' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r4a2 = a2 >= b2;
                ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '>=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r4a3 = a3 >= b3;
                ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '>=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r4b1 = b1 >= a1;
                ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '>=' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r4b2 = b2 >= a2;
                ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '>=' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r4b3 = b3 >= a3;
                ~~~~~~~~
-!!! error TS2365: Operator '>=' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+!!! error TS2365: Operator '>=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator ==
     var r5a1 = a1 == b1;
                ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '==' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r5a2 = a2 == b2;
                ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r5a3 = a3 == b3;
                ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '==' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r5b1 = b1 == a1;
                ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '==' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r5b2 = b2 == a2;
                ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '==' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r5b3 = b3 == a3;
                ~~~~~~~~
-!!! error TS2365: Operator '==' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+!!! error TS2365: Operator '==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator !=
     var r6a1 = a1 != b1;
                ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '!=' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r6a2 = a2 != b2;
                ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '!=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r6a3 = a3 != b3;
                ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '!=' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r6b1 = b1 != a1;
                ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '!=' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r6b2 = b2 != a2;
                ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '!=' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r6b3 = b3 != a3;
                ~~~~~~~~
-!!! error TS2365: Operator '!=' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+!!! error TS2365: Operator '!=' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator ===
     var r7a1 = a1 === b1;
                ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '===' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r7a2 = a2 === b2;
                ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '===' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r7a3 = a3 === b3;
                ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '===' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r7b1 = b1 === a1;
                ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '===' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r7b2 = b2 === a2;
                ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '===' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r7b3 = b3 === a3;
                ~~~~~~~~~
-!!! error TS2365: Operator '===' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
+!!! error TS2365: Operator '===' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
     
     // operator !==
     var r8a1 = a1 !== b1;
                ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: string; }' and '{ [x: string]: number; }'.
+!!! error TS2365: Operator '!==' cannot be applied to types '{ [a: string]: string; }' and '{ [b: string]: number; }'.
     var r8a2 = a2 !== b2;
                ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: Base; }' and '{ [x: string]: C; }'.
+!!! error TS2365: Operator '!==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: string]: C; }'.
     var r8a3 = a3 !== b3;
                ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [x: number]: Base; }' and '{ [x: number]: C; }'.
+!!! 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 '{ [x: number]: Derived; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '!==' cannot be applied to types '{ [index: number]: Derived; }' and '{ [index: string]: Base; }'.
     
     var r8b1 = b1 !== a1;
                ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: number; }' and '{ [x: string]: string; }'.
+!!! error TS2365: Operator '!==' cannot be applied to types '{ [b: string]: number; }' and '{ [a: string]: string; }'.
     var r8b2 = b2 !== a2;
                ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [x: string]: C; }' and '{ [x: string]: Base; }'.
+!!! error TS2365: Operator '!==' cannot be applied to types '{ [index: string]: C; }' and '{ [index: string]: Base; }'.
     var r8b3 = b3 !== a3;
                ~~~~~~~~~
-!!! error TS2365: Operator '!==' cannot be applied to types '{ [x: number]: C; }' and '{ [x: number]: Base; }'.
+!!! 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 '{ [x: string]: Base; }' and '{ [x: number]: Derived; }'.
\ No newline at end of file
+!!! error TS2365: Operator '!==' cannot be applied to types '{ [index: string]: Base; }' and '{ [index: number]: Derived; }'.
\ No newline at end of file
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.types b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.types
index 755df0be1dc..657fdccbda0 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.types
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnIndexSignature.types
@@ -15,38 +15,38 @@ class Derived extends Base {
 }
 
 var a1: { [a: string]: string };
->a1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
 >a : string
 
 var b1: { [b: string]: string };
->b1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
 >b : string
 
 var a2: { [index: string]: Base };
->a2 : { [x: string]: Base; }
+>a2 : { [index: string]: Base; }
 >index : string
 >Base : Base
 
 var b2: { [index: string]: Derived };
->b2 : { [x: string]: Derived; }
+>b2 : { [index: string]: Derived; }
 >index : string
 >Derived : Derived
 
 var a3: { [index: number]: string };
->a3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
 >index : number
 
 var b3: { [index: number]: string };
->b3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
 >index : number
 
 var a4: { [index: number]: Base };
->a4 : { [x: number]: Base; }
+>a4 : { [index: number]: Base; }
 >index : number
 >Base : Base
 
 var b4: { [index: string]: Derived };
->b4 : { [x: string]: Derived; }
+>b4 : { [index: string]: Derived; }
 >index : string
 >Derived : Derived
 
@@ -54,391 +54,391 @@ var b4: { [index: string]: Derived };
 var r1a1 = a1 < b1;
 >r1a1 : boolean
 >a1 < b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r1a1 = a2 < b2;
 >r1a1 : boolean
 >a2 < b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r1a1 = a3 < b3;
 >r1a1 : boolean
 >a3 < b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r1a1 = a4 < b4;
 >r1a1 : boolean
 >a4 < b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r1b1 = b1 < a1;
 >r1b1 : boolean
 >b1 < a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r1b1 = b2 < a2;
 >r1b1 : boolean
 >b2 < a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r1b1 = b3 < a3;
 >r1b1 : boolean
 >b3 < a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r1b1 = b4 < a4;
 >r1b1 : boolean
 >b4 < a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
 // operator >
 var r2a1 = a1 > b1;
 >r2a1 : boolean
 >a1 > b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r2a1 = a2 > b2;
 >r2a1 : boolean
 >a2 > b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r2a1 = a3 > b3;
 >r2a1 : boolean
 >a3 > b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r2a1 = a4 > b4;
 >r2a1 : boolean
 >a4 > b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r2b1 = b1 > a1;
 >r2b1 : boolean
 >b1 > a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r2b1 = b2 > a2;
 >r2b1 : boolean
 >b2 > a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r2b1 = b3 > a3;
 >r2b1 : boolean
 >b3 > a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r2b1 = b4 > a4;
 >r2b1 : boolean
 >b4 > a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
 // operator <=
 var r3a1 = a1 <= b1;
 >r3a1 : boolean
 >a1 <= b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r3a1 = a2 <= b2;
 >r3a1 : boolean
 >a2 <= b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r3a1 = a3 <= b3;
 >r3a1 : boolean
 >a3 <= b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r3a1 = a4 <= b4;
 >r3a1 : boolean
 >a4 <= b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r3b1 = b1 <= a1;
 >r3b1 : boolean
 >b1 <= a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r3b1 = b2 <= a2;
 >r3b1 : boolean
 >b2 <= a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r3b1 = b3 <= a3;
 >r3b1 : boolean
 >b3 <= a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r3b1 = b4 <= a4;
 >r3b1 : boolean
 >b4 <= a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
 // operator >=
 var r4a1 = a1 >= b1;
 >r4a1 : boolean
 >a1 >= b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r4a1 = a2 >= b2;
 >r4a1 : boolean
 >a2 >= b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r4a1 = a3 >= b3;
 >r4a1 : boolean
 >a3 >= b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r4a1 = a4 >= b4;
 >r4a1 : boolean
 >a4 >= b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r4b1 = b1 >= a1;
 >r4b1 : boolean
 >b1 >= a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r4b1 = b2 >= a2;
 >r4b1 : boolean
 >b2 >= a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r4b1 = b3 >= a3;
 >r4b1 : boolean
 >b3 >= a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r4b1 = b4 >= a4;
 >r4b1 : boolean
 >b4 >= a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
 // operator ==
 var r5a1 = a1 == b1;
 >r5a1 : boolean
 >a1 == b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r5a1 = a2 == b2;
 >r5a1 : boolean
 >a2 == b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r5a1 = a3 == b3;
 >r5a1 : boolean
 >a3 == b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r5a1 = a4 == b4;
 >r5a1 : boolean
 >a4 == b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r5b1 = b1 == a1;
 >r5b1 : boolean
 >b1 == a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r5b1 = b2 == a2;
 >r5b1 : boolean
 >b2 == a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r5b1 = b3 == a3;
 >r5b1 : boolean
 >b3 == a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r5b1 = b4 == a4;
 >r5b1 : boolean
 >b4 == a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
 // operator !=
 var r6a1 = a1 != b1;
 >r6a1 : boolean
 >a1 != b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r6a1 = a2 != b2;
 >r6a1 : boolean
 >a2 != b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r6a1 = a3 != b3;
 >r6a1 : boolean
 >a3 != b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r6a1 = a4 != b4;
 >r6a1 : boolean
 >a4 != b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r6b1 = b1 != a1;
 >r6b1 : boolean
 >b1 != a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r6b1 = b2 != a2;
 >r6b1 : boolean
 >b2 != a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r6b1 = b3 != a3;
 >r6b1 : boolean
 >b3 != a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r6b1 = b4 != a4;
 >r6b1 : boolean
 >b4 != a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
 // operator ===
 var r7a1 = a1 === b1;
 >r7a1 : boolean
 >a1 === b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r7a1 = a2 === b2;
 >r7a1 : boolean
 >a2 === b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r7a1 = a3 === b3;
 >r7a1 : boolean
 >a3 === b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r7a1 = a4 === b4;
 >r7a1 : boolean
 >a4 === b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r7b1 = b1 === a1;
 >r7b1 : boolean
 >b1 === a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r7b1 = b2 === a2;
 >r7b1 : boolean
 >b2 === a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r7b1 = b3 === a3;
 >r7b1 : boolean
 >b3 === a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r7b1 = b4 === a4;
 >r7b1 : boolean
 >b4 === a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
 // operator !==
 var r8a1 = a1 !== b1;
 >r8a1 : boolean
 >a1 !== b1 : boolean
->a1 : { [x: string]: string; }
->b1 : { [x: string]: string; }
+>a1 : { [a: string]: string; }
+>b1 : { [b: string]: string; }
 
 var r8a1 = a2 !== b2;
 >r8a1 : boolean
 >a2 !== b2 : boolean
->a2 : { [x: string]: Base; }
->b2 : { [x: string]: Derived; }
+>a2 : { [index: string]: Base; }
+>b2 : { [index: string]: Derived; }
 
 var r8a1 = a3 !== b3;
 >r8a1 : boolean
 >a3 !== b3 : boolean
->a3 : { [x: number]: string; }
->b3 : { [x: number]: string; }
+>a3 : { [index: number]: string; }
+>b3 : { [index: number]: string; }
 
 var r8a1 = a4 !== b4;
 >r8a1 : boolean
 >a4 !== b4 : boolean
->a4 : { [x: number]: Base; }
->b4 : { [x: string]: Derived; }
+>a4 : { [index: number]: Base; }
+>b4 : { [index: string]: Derived; }
 
 var r8b1 = b1 !== a1;
 >r8b1 : boolean
 >b1 !== a1 : boolean
->b1 : { [x: string]: string; }
->a1 : { [x: string]: string; }
+>b1 : { [b: string]: string; }
+>a1 : { [a: string]: string; }
 
 var r8b1 = b2 !== a2;
 >r8b1 : boolean
 >b2 !== a2 : boolean
->b2 : { [x: string]: Derived; }
->a2 : { [x: string]: Base; }
+>b2 : { [index: string]: Derived; }
+>a2 : { [index: string]: Base; }
 
 var r8b1 = b3 !== a3;
 >r8b1 : boolean
 >b3 !== a3 : boolean
->b3 : { [x: number]: string; }
->a3 : { [x: number]: string; }
+>b3 : { [index: number]: string; }
+>a3 : { [index: number]: string; }
 
 var r8b1 = b4 !== a4;
 >r8b1 : boolean
 >b4 !== a4 : boolean
->b4 : { [x: string]: Derived; }
->a4 : { [x: number]: Base; }
+>b4 : { [index: string]: Derived; }
+>a4 : { [index: number]: Base; }
 
diff --git a/tests/baselines/reference/contextualTypeAny.types b/tests/baselines/reference/contextualTypeAny.types
index c95bfd70ecf..b21c3748eda 100644
--- a/tests/baselines/reference/contextualTypeAny.types
+++ b/tests/baselines/reference/contextualTypeAny.types
@@ -3,7 +3,7 @@ var x: any;
 >x : any
 
 var obj: { [s: string]: number } = { p: "", q: x };
->obj : { [x: string]: number; }
+>obj : { [s: string]: number; }
 >s : string
 >{ p: "", q: x } : { [x: string]: any; p: string; q: any; }
 >p : string
diff --git a/tests/baselines/reference/contextualTypingOfObjectLiterals.errors.txt b/tests/baselines/reference/contextualTypingOfObjectLiterals.errors.txt
index b388d1b0e4a..5d41b312f72 100644
--- a/tests/baselines/reference/contextualTypingOfObjectLiterals.errors.txt
+++ b/tests/baselines/reference/contextualTypingOfObjectLiterals.errors.txt
@@ -1,6 +1,6 @@
 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 '{ [x: string]: 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; }'.
 
 
 ==== tests/cases/compiler/contextualTypingOfObjectLiterals.ts (2 errors) ====
@@ -18,4 +18,4 @@ tests/cases/compiler/contextualTypingOfObjectLiterals.ts(10,3): error TS2345: Ar
     f(obj1); // Ok
     f(obj2); // Error - indexer doesn't match
       ~~~~
-!!! error TS2345: Argument of type '{ x: string; }' is not assignable to parameter of type '{ [x: string]: string; }'.
\ No newline at end of file
+!!! error TS2345: Argument of type '{ x: string; }' is not assignable to parameter of type '{ [s: string]: string; }'.
\ No newline at end of file
diff --git a/tests/baselines/reference/declFileTypeAnnotationTypeLiteral.types b/tests/baselines/reference/declFileTypeAnnotationTypeLiteral.types
index 432ee1506fa..30d14b77286 100644
--- a/tests/baselines/reference/declFileTypeAnnotationTypeLiteral.types
+++ b/tests/baselines/reference/declFileTypeAnnotationTypeLiteral.types
@@ -17,7 +17,7 @@ module m {
 
 // Object literal with everything
 var x: {
->x : { (a: number): c; (a: string): g<string>; new (a: number): c; new (a: string): m.c; [x: string]: c; [x: number]: c; a: c; b: g<string>; m1(): g<number>; m2(a: string, b?: number, ...c: c[]): string; }
+>x : { (a: number): c; (a: string): g<string>; new (a: number): c; new (a: string): m.c; [n: string]: c; [n: number]: c; a: c; b: g<string>; m1(): g<number>; m2(a: string, b?: number, ...c: c[]): string; }
 
     // Call signatures
     (a: number): c;
diff --git a/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types b/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types
index 991d324e822..6525f201f5b 100644
--- a/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types
+++ b/tests/baselines/reference/extendingClassFromAliasAndUsageInIndexer.types
@@ -22,7 +22,7 @@ var moduleATyped: IHasVisualizationModel = moduleA;
 >moduleA : typeof moduleA
 
 var moduleMap: { [key: string]: IHasVisualizationModel } = {
->moduleMap : { [x: string]: IHasVisualizationModel; }
+>moduleMap : { [key: string]: IHasVisualizationModel; }
 >key : string
 >IHasVisualizationModel : IHasVisualizationModel
 >{    "moduleA": moduleA,    "moduleB": moduleB} : { [x: string]: typeof moduleA; "moduleA": typeof moduleA; "moduleB": typeof moduleB; }
@@ -42,7 +42,7 @@ var visModel = new moduleMap[moduleName].VisualizationModel();
 >new moduleMap[moduleName].VisualizationModel() : Backbone.Model
 >moduleMap[moduleName].VisualizationModel : typeof Backbone.Model
 >moduleMap[moduleName] : IHasVisualizationModel
->moduleMap : { [x: string]: IHasVisualizationModel; }
+>moduleMap : { [key: string]: IHasVisualizationModel; }
 >moduleName : string
 >VisualizationModel : typeof Backbone.Model
 
diff --git a/tests/baselines/reference/generatedContextualTyping.types b/tests/baselines/reference/generatedContextualTyping.types
index 79787f6d994..423c5d6653b 100644
--- a/tests/baselines/reference/generatedContextualTyping.types
+++ b/tests/baselines/reference/generatedContextualTyping.types
@@ -97,7 +97,7 @@ var x8: Array<Base> = [d1, d2];
 >d2 : Derived2
 
 var x9: { [n: number]: Base; } = [d1, d2];
->x9 : { [x: number]: Base; }
+>x9 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -210,7 +210,7 @@ class x20 { member: Array<Base> = [d1, d2] }
 
 class x21 { member: { [n: number]: Base; } = [d1, d2] }
 >x21 : x21
->member : { [x: number]: Base; }
+>member : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -326,7 +326,7 @@ class x32 { private member: Array<Base> = [d1, d2] }
 
 class x33 { private member: { [n: number]: Base; } = [d1, d2] }
 >x33 : x33
->member : { [x: number]: Base; }
+>member : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -442,7 +442,7 @@ class x44 { public member: Array<Base> = [d1, d2] }
 
 class x45 { public member: { [n: number]: Base; } = [d1, d2] }
 >x45 : x45
->member : { [x: number]: Base; }
+>member : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -558,7 +558,7 @@ class x56 { static member: Array<Base> = [d1, d2] }
 
 class x57 { static member: { [n: number]: Base; } = [d1, d2] }
 >x57 : x57
->member : { [x: number]: Base; }
+>member : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -674,7 +674,7 @@ class x68 { private static member: Array<Base> = [d1, d2] }
 
 class x69 { private static member: { [n: number]: Base; } = [d1, d2] }
 >x69 : x69
->member : { [x: number]: Base; }
+>member : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -790,7 +790,7 @@ class x80 { public static member: Array<Base> = [d1, d2] }
 
 class x81 { public static member: { [n: number]: Base; } = [d1, d2] }
 >x81 : x81
->member : { [x: number]: Base; }
+>member : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -906,7 +906,7 @@ class x92 { constructor(parm: Array<Base> = [d1, d2]) { } }
 
 class x93 { constructor(parm: { [n: number]: Base; } = [d1, d2]) { } }
 >x93 : x93
->parm : { [x: number]: Base; }
+>parm : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -1022,7 +1022,7 @@ class x104 { constructor(public parm: Array<Base> = [d1, d2]) { } }
 
 class x105 { constructor(public parm: { [n: number]: Base; } = [d1, d2]) { } }
 >x105 : x105
->parm : { [x: number]: Base; }
+>parm : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -1138,7 +1138,7 @@ class x116 { constructor(private parm: Array<Base> = [d1, d2]) { } }
 
 class x117 { constructor(private parm: { [n: number]: Base; } = [d1, d2]) { } }
 >x117 : x117
->parm : { [x: number]: Base; }
+>parm : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -1253,8 +1253,8 @@ function x128(parm: Array<Base> = [d1, d2]) { }
 >d2 : Derived2
 
 function x129(parm: { [n: number]: Base; } = [d1, d2]) { }
->x129 : (parm?: { [x: number]: Base; }) => void
->parm : { [x: number]: Base; }
+>x129 : (parm?: { [n: number]: Base; }) => void
+>parm : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -1361,7 +1361,7 @@ function x140(): Array<Base> { return [d1, d2]; }
 >d2 : Derived2
 
 function x141(): { [n: number]: Base; } { return [d1, d2]; }
->x141 : () => { [x: number]: Base; }
+>x141 : () => { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -1497,7 +1497,7 @@ function x152(): Array<Base> { return [d1, d2]; return [d1, d2]; }
 >d2 : Derived2
 
 function x153(): { [n: number]: Base; } { return [d1, d2]; return [d1, d2]; }
->x153 : () => { [x: number]: Base; }
+>x153 : () => { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -1628,7 +1628,7 @@ var x164: () => Array<Base> = () => { return [d1, d2]; };
 >d2 : Derived2
 
 var x165: () => { [n: number]: Base; } = () => { return [d1, d2]; };
->x165 : () => { [x: number]: Base; }
+>x165 : () => { [n: number]: Base; }
 >n : number
 >Base : Base
 >() => { return [d1, d2]; } : () => (Derived1 | Derived2)[]
@@ -1744,7 +1744,7 @@ var x176: () => Array<Base> = function() { return [d1, d2]; };
 >d2 : Derived2
 
 var x177: () => { [n: number]: Base; } = function() { return [d1, d2]; };
->x177 : () => { [x: number]: Base; }
+>x177 : () => { [n: number]: Base; }
 >n : number
 >Base : Base
 >function() { return [d1, d2]; } : () => (Derived1 | Derived2)[]
@@ -1861,7 +1861,7 @@ module x188 { var t: Array<Base> = [d1, d2]; }
 
 module x189 { var t: { [n: number]: Base; } = [d1, d2]; }
 >x189 : typeof x189
->t : { [x: number]: Base; }
+>t : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -1977,7 +1977,7 @@ module x200 { export var t: Array<Base> = [d1, d2]; }
 
 module x201 { export var t: { [n: number]: Base; } = [d1, d2]; }
 >x201 : typeof x201
->t : { [x: number]: Base; }
+>t : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -2074,8 +2074,8 @@ var x212 = <Array<Base>>[d1, d2];
 >d2 : Derived2
 
 var x213 = <{ [n: number]: Base; }>[d1, d2];
->x213 : { [x: number]: Base; }
-><{ [n: number]: Base; }>[d1, d2] : { [x: number]: Base; }
+>x213 : { [n: number]: Base; }
+><{ [n: number]: Base; }>[d1, d2] : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] : (Derived1 | Derived2)[]
@@ -2180,10 +2180,10 @@ var x222 = (<Array<Base>>undefined) || [d1, d2];
 >d2 : Derived2
 
 var x223 = (<{ [n: number]: Base; }>undefined) || [d1, d2];
->x223 : { [x: number]: Base; }
->(<{ [n: number]: Base; }>undefined) || [d1, d2] : { [x: number]: Base; }
->(<{ [n: number]: Base; }>undefined) : { [x: number]: Base; }
-><{ [n: number]: Base; }>undefined : { [x: number]: Base; }
+>x223 : { [n: number]: Base; }
+>(<{ [n: number]: Base; }>undefined) || [d1, d2] : { [n: number]: Base; }
+>(<{ [n: number]: Base; }>undefined) : { [n: number]: Base; }
+><{ [n: number]: Base; }>undefined : { [n: number]: Base; }
 >n : number
 >Base : Base
 >undefined : undefined
@@ -2287,11 +2287,11 @@ var x232: Array<Base>; x232 = [d1, d2];
 >d2 : Derived2
 
 var x233: { [n: number]: Base; }; x233 = [d1, d2];
->x233 : { [x: number]: Base; }
+>x233 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >x233 = [d1, d2] : (Derived1 | Derived2)[]
->x233 : { [x: number]: Base; }
+>x233 : { [n: number]: Base; }
 >[d1, d2] : (Derived1 | Derived2)[]
 >d1 : Derived1
 >d2 : Derived2
@@ -2423,8 +2423,8 @@ var x244: { n: Array<Base>; } = { n: [d1, d2] };
 >d2 : Derived2
 
 var x245: { n: { [n: number]: Base; }; } = { n: [d1, d2] };
->x245 : { n: { [x: number]: Base; }; }
->n : { [x: number]: Base; }
+>x245 : { n: { [n: number]: Base; }; }
+>n : { [n: number]: Base; }
 >n : number
 >Base : Base
 >{ n: [d1, d2] } : { n: (Derived1 | Derived2)[]; }
@@ -2519,7 +2519,7 @@ var x256: Array<Base>[] = [[d1, d2]];
 >d2 : Derived2
 
 var x257: { [n: number]: Base; }[] = [[d1, d2]];
->x257 : { [x: number]: Base; }[]
+>x257 : { [n: number]: Base; }[]
 >n : number
 >Base : Base
 >[[d1, d2]] : (Derived1 | Derived2)[][]
@@ -2613,7 +2613,7 @@ var x266: Array<Base> = [d1, d2] || undefined;
 >undefined : undefined
 
 var x267: { [n: number]: Base; } = [d1, d2] || undefined;
->x267 : { [x: number]: Base; }
+>x267 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] || undefined : (Derived1 | Derived2)[]
@@ -2696,7 +2696,7 @@ var x274: Array<Base> = undefined || [d1, d2];
 >d2 : Derived2
 
 var x275: { [n: number]: Base; } = undefined || [d1, d2];
->x275 : { [x: number]: Base; }
+>x275 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >undefined || [d1, d2] : (Derived1 | Derived2)[]
@@ -2797,7 +2797,7 @@ var x282: Array<Base> = [d1, d2] || [d1, d2];
 >d2 : Derived2
 
 var x283: { [n: number]: Base; } = [d1, d2] || [d1, d2];
->x283 : { [x: number]: Base; }
+>x283 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >[d1, d2] || [d1, d2] : (Derived1 | Derived2)[]
@@ -2930,7 +2930,7 @@ var x292: Array<Base> = true ? [d1, d2] : [d1, d2];
 >d2 : Derived2
 
 var x293: { [n: number]: Base; } = true ? [d1, d2] : [d1, d2];
->x293 : { [x: number]: Base; }
+>x293 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >true ? [d1, d2] : [d1, d2] : (Derived1 | Derived2)[]
@@ -3073,7 +3073,7 @@ var x304: Array<Base> = true ? undefined : [d1, d2];
 >d2 : Derived2
 
 var x305: { [n: number]: Base; } = true ? undefined : [d1, d2];
->x305 : { [x: number]: Base; }
+>x305 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >true ? undefined : [d1, d2] : (Derived1 | Derived2)[]
@@ -3201,7 +3201,7 @@ var x316: Array<Base> = true ? [d1, d2] : undefined;
 >undefined : undefined
 
 var x317: { [n: number]: Base; } = true ? [d1, d2] : undefined;
->x317 : { [x: number]: Base; }
+>x317 : { [n: number]: Base; }
 >n : number
 >Base : Base
 >true ? [d1, d2] : undefined : (Derived1 | Derived2)[]
@@ -3337,12 +3337,12 @@ function x328(n: Array<Base>) { }; x328([d1, d2]);
 >d2 : Derived2
 
 function x329(n: { [n: number]: Base; }) { }; x329([d1, d2]);
->x329 : (n: { [x: number]: Base; }) => void
->n : { [x: number]: Base; }
+>x329 : (n: { [n: number]: Base; }) => void
+>n : { [n: number]: Base; }
 >n : number
 >Base : Base
 >x329([d1, d2]) : void
->x329 : (n: { [x: number]: Base; }) => void
+>x329 : (n: { [n: number]: Base; }) => void
 >[d1, d2] : (Derived1 | Derived2)[]
 >d1 : Derived1
 >d2 : Derived2
@@ -3493,14 +3493,14 @@ var x340 = (n: Array<Base>) => n; x340([d1, d2]);
 >d2 : Derived2
 
 var x341 = (n: { [n: number]: Base; }) => n; x341([d1, d2]);
->x341 : (n: { [x: number]: Base; }) => { [x: number]: Base; }
->(n: { [n: number]: Base; }) => n : (n: { [x: number]: Base; }) => { [x: number]: Base; }
->n : { [x: number]: Base; }
+>x341 : (n: { [n: number]: Base; }) => { [n: number]: Base; }
+>(n: { [n: number]: Base; }) => n : (n: { [n: number]: Base; }) => { [n: number]: Base; }
+>n : { [n: number]: Base; }
 >n : number
 >Base : Base
->n : { [x: number]: Base; }
->x341([d1, d2]) : { [x: number]: Base; }
->x341 : (n: { [x: number]: Base; }) => { [x: number]: Base; }
+>n : { [n: number]: Base; }
+>x341([d1, d2]) : { [n: number]: Base; }
+>x341 : (n: { [n: number]: Base; }) => { [n: number]: Base; }
 >[d1, d2] : (Derived1 | Derived2)[]
 >d1 : Derived1
 >d2 : Derived2
@@ -3649,13 +3649,13 @@ var x352 = function(n: Array<Base>) { }; x352([d1, d2]);
 >d2 : Derived2
 
 var x353 = function(n: { [n: number]: Base; }) { }; x353([d1, d2]);
->x353 : (n: { [x: number]: Base; }) => void
->function(n: { [n: number]: Base; }) { } : (n: { [x: number]: Base; }) => void
->n : { [x: number]: Base; }
+>x353 : (n: { [n: number]: Base; }) => void
+>function(n: { [n: number]: Base; }) { } : (n: { [n: number]: Base; }) => void
+>n : { [n: number]: Base; }
 >n : number
 >Base : Base
 >x353([d1, d2]) : void
->x353 : (n: { [x: number]: Base; }) => void
+>x353 : (n: { [n: number]: Base; }) => void
 >[d1, d2] : (Derived1 | Derived2)[]
 >d1 : Derived1
 >d2 : Derived2
diff --git a/tests/baselines/reference/genericBaseClassLiteralProperty2.types b/tests/baselines/reference/genericBaseClassLiteralProperty2.types
index 9caa45b8b8f..2ade6437fe7 100644
--- a/tests/baselines/reference/genericBaseClassLiteralProperty2.types
+++ b/tests/baselines/reference/genericBaseClassLiteralProperty2.types
@@ -8,16 +8,16 @@ class BaseCollection2<TItem extends CollectionItem2> {
 >CollectionItem2 : CollectionItem2
 
     _itemsByKey: { [key: string]: TItem; };
->_itemsByKey : { [x: string]: TItem; }
+>_itemsByKey : { [key: string]: TItem; }
 >key : string
 >TItem : TItem
 
     constructor() {
         this._itemsByKey = {};
 >this._itemsByKey = {} : { [x: string]: undefined; }
->this._itemsByKey : { [x: string]: TItem; }
+>this._itemsByKey : { [key: string]: TItem; }
 >this : BaseCollection2<TItem>
->_itemsByKey : { [x: string]: TItem; }
+>_itemsByKey : { [key: string]: TItem; }
 >{} : { [x: string]: undefined; }
     }
 }
@@ -35,9 +35,9 @@ class DataView2 extends BaseCollection2<CollectionItem2> {
         this._itemsByKey['dummy'] = item;
 >this._itemsByKey['dummy'] = item : CollectionItem2
 >this._itemsByKey['dummy'] : CollectionItem2
->this._itemsByKey : { [x: string]: CollectionItem2; }
+>this._itemsByKey : { [key: string]: CollectionItem2; }
 >this : DataView2
->_itemsByKey : { [x: string]: CollectionItem2; }
+>_itemsByKey : { [key: string]: CollectionItem2; }
 >item : CollectionItem2
     }
 }
diff --git a/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types b/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types
index f0cab6e7467..ef42c1c6029 100644
--- a/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types
+++ b/tests/baselines/reference/genericWithIndexerOfTypeParameterType1.types
@@ -4,19 +4,19 @@ class LazyArray<T> {
 >T : T
 
     private objects = <{ [objectId: string]: T; }>{};
->objects : { [x: string]: T; }
-><{ [objectId: string]: T; }>{} : { [x: string]: T; }
+>objects : { [objectId: string]: T; }
+><{ [objectId: string]: T; }>{} : { [objectId: string]: T; }
 >objectId : string
 >T : T
 >{} : { [x: string]: undefined; }
 
     array() {
->array : () => { [x: string]: T; }
+>array : () => { [objectId: string]: T; }
 
         return this.objects;
->this.objects : { [x: string]: T; }
+>this.objects : { [objectId: string]: T; }
 >this : LazyArray<T>
->objects : { [x: string]: T; }
+>objects : { [objectId: string]: T; }
     }
 }
 var lazyArray = new LazyArray<string>();
@@ -27,8 +27,8 @@ var lazyArray = new LazyArray<string>();
 var value: string = lazyArray.array()["test"]; // used to be an error
 >value : string
 >lazyArray.array()["test"] : string
->lazyArray.array() : { [x: string]: string; }
->lazyArray.array : () => { [x: string]: string; }
+>lazyArray.array() : { [objectId: string]: string; }
+>lazyArray.array : () => { [objectId: string]: string; }
 >lazyArray : LazyArray<string>
->array : () => { [x: string]: string; }
+>array : () => { [objectId: string]: string; }
 
diff --git a/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.types b/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.types
index 1de9b6d2aa8..e1cdfa85f13 100644
--- a/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.types
+++ b/tests/baselines/reference/genericWithIndexerOfTypeParameterType2.types
@@ -5,7 +5,7 @@ export class Collection<TItem extends CollectionItem> {
 >CollectionItem : CollectionItem
 
     _itemsByKey: { [key: string]: TItem; };
->_itemsByKey : { [x: string]: TItem; }
+>_itemsByKey : { [key: string]: TItem; }
 >key : string
 >TItem : TItem
 }
diff --git a/tests/baselines/reference/indexSignaturesInferentialTyping.types b/tests/baselines/reference/indexSignaturesInferentialTyping.types
index 4054ccca227..9ea5a390498 100644
--- a/tests/baselines/reference/indexSignaturesInferentialTyping.types
+++ b/tests/baselines/reference/indexSignaturesInferentialTyping.types
@@ -1,17 +1,17 @@
 === tests/cases/compiler/indexSignaturesInferentialTyping.ts ===
 function foo<T>(items: { [index: number]: T }): T { return undefined; }
->foo : <T>(items: { [x: number]: T; }) => T
+>foo : <T>(items: { [index: number]: T; }) => T
 >T : T
->items : { [x: number]: T; }
+>items : { [index: number]: T; }
 >index : number
 >T : T
 >T : T
 >undefined : undefined
 
 function bar<T>(items: { [index: string]: T }): T { return undefined; }
->bar : <T>(items: { [x: string]: T; }) => T
+>bar : <T>(items: { [index: string]: T; }) => T
 >T : T
->items : { [x: string]: T; }
+>items : { [index: string]: T; }
 >index : string
 >T : T
 >T : T
@@ -20,13 +20,13 @@ function bar<T>(items: { [index: string]: T }): T { return undefined; }
 var x1 = foo({ 0: 0, 1: 1 });       // type should be number
 >x1 : number
 >foo({ 0: 0, 1: 1 }) : number
->foo : <T>(items: { [x: number]: T; }) => T
+>foo : <T>(items: { [index: number]: T; }) => T
 >{ 0: 0, 1: 1 } : { [x: number]: number; 0: number; 1: number; }
 
 var x2 = foo({ zero: 0, one: 1 });
 >x2 : any
 >foo({ zero: 0, one: 1 }) : any
->foo : <T>(items: { [x: number]: T; }) => T
+>foo : <T>(items: { [index: number]: T; }) => T
 >{ zero: 0, one: 1 } : { [x: number]: undefined; zero: number; one: number; }
 >zero : number
 >one : number
@@ -34,13 +34,13 @@ var x2 = foo({ zero: 0, one: 1 });
 var x3 = bar({ 0: 0, 1: 1 });
 >x3 : number
 >bar({ 0: 0, 1: 1 }) : number
->bar : <T>(items: { [x: string]: T; }) => T
+>bar : <T>(items: { [index: string]: T; }) => T
 >{ 0: 0, 1: 1 } : { [x: string]: number; 0: number; 1: number; }
 
 var x4 = bar({ zero: 0, one: 1 });  // type should be number
 >x4 : number
 >bar({ zero: 0, one: 1 }) : number
->bar : <T>(items: { [x: string]: T; }) => T
+>bar : <T>(items: { [index: string]: T; }) => T
 >{ zero: 0, one: 1 } : { [x: string]: number; zero: number; one: number; }
 >zero : number
 >one : number
diff --git a/tests/baselines/reference/indexerAssignability.errors.txt b/tests/baselines/reference/indexerAssignability.errors.txt
index 9f28fc1e9e0..44c2184517e 100644
--- a/tests/baselines/reference/indexerAssignability.errors.txt
+++ b/tests/baselines/reference/indexerAssignability.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/compiler/indexerAssignability.ts(5,1): error TS2322: Type '{ [x: number]: string; }' is not assignable to type '{ [x: string]: string; }'.
-  Index signature is missing in type '{ [x: number]: string; }'.
-tests/cases/compiler/indexerAssignability.ts(6,1): error TS2322: Type '{}' is not assignable to type '{ [x: string]: string; }'.
+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 '{ [x: number]: string; }'.
+tests/cases/compiler/indexerAssignability.ts(8,1): error TS2322: Type '{}' is not assignable to type '{ [n: number]: string; }'.
   Index signature is missing in type '{}'.
 
 
@@ -13,16 +13,16 @@ tests/cases/compiler/indexerAssignability.ts(8,1): error TS2322: Type '{}' is no
     
     a = b;
     ~
-!!! error TS2322: Type '{ [x: number]: string; }' is not assignable to type '{ [x: string]: string; }'.
-!!! error TS2322:   Index signature is missing in type '{ [x: number]: string; }'.
+!!! 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 '{ [x: string]: string; }'.
+!!! 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 '{ [x: number]: string; }'.
+!!! 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/indexerReturningTypeParameter1.types b/tests/baselines/reference/indexerReturningTypeParameter1.types
index 55155323c84..a0a70f95331 100644
--- a/tests/baselines/reference/indexerReturningTypeParameter1.types
+++ b/tests/baselines/reference/indexerReturningTypeParameter1.types
@@ -3,7 +3,7 @@ interface f {
 >f : f
 
     groupBy<T>(): { [key: string]: T[]; };
->groupBy : <T>() => { [x: string]: T[]; }
+>groupBy : <T>() => { [key: string]: T[]; }
 >T : T
 >key : string
 >T : T
@@ -13,17 +13,17 @@ var a: f;
 >f : f
 
 var r = a.groupBy();
->r : { [x: string]: {}[]; }
->a.groupBy() : { [x: string]: {}[]; }
->a.groupBy : <T>() => { [x: string]: T[]; }
+>r : { [key: string]: {}[]; }
+>a.groupBy() : { [key: string]: {}[]; }
+>a.groupBy : <T>() => { [key: string]: T[]; }
 >a : f
->groupBy : <T>() => { [x: string]: T[]; }
+>groupBy : <T>() => { [key: string]: T[]; }
 
 class c {
 >c : c
 
     groupBy<T>(): { [key: string]: T[]; } {
->groupBy : <T>() => { [x: string]: T[]; }
+>groupBy : <T>() => { [key: string]: T[]; }
 >T : T
 >key : string
 >T : T
@@ -36,9 +36,9 @@ var a2: c;
 >c : c
 
 var r2 = a2.groupBy();
->r2 : { [x: string]: {}[]; }
->a2.groupBy() : { [x: string]: {}[]; }
->a2.groupBy : <T>() => { [x: string]: T[]; }
+>r2 : { [key: string]: {}[]; }
+>a2.groupBy() : { [key: string]: {}[]; }
+>a2.groupBy : <T>() => { [key: string]: T[]; }
 >a2 : c
->groupBy : <T>() => { [x: string]: T[]; }
+>groupBy : <T>() => { [key: string]: T[]; }
 
diff --git a/tests/baselines/reference/nestedIndexer.types b/tests/baselines/reference/nestedIndexer.types
index 612f6a260b7..ade8dbbcb66 100644
--- a/tests/baselines/reference/nestedIndexer.types
+++ b/tests/baselines/reference/nestedIndexer.types
@@ -4,7 +4,7 @@ function then(x) {
 >x : any
 
 var match: { [index: number]: string; }
->match : { [x: number]: string; }
+>match : { [index: number]: string; }
 >index : number
 
 }
diff --git a/tests/baselines/reference/numericIndexerConstraint2.errors.txt b/tests/baselines/reference/numericIndexerConstraint2.errors.txt
index 4260f60becf..385efbcead2 100644
--- a/tests/baselines/reference/numericIndexerConstraint2.errors.txt
+++ b/tests/baselines/reference/numericIndexerConstraint2.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/numericIndexerConstraint2.ts(4,1): error TS2322: Type '{ one: number; }' is not assignable to type '{ [x: string]: Foo; }'.
+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; }'.
 
 
@@ -8,5 +8,5 @@ tests/cases/compiler/numericIndexerConstraint2.ts(4,1): error TS2322: Type '{ on
     var a: { one: number; };
     x = a;
     ~
-!!! error TS2322: Type '{ one: number; }' is not assignable to type '{ [x: string]: Foo; }'.
+!!! 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
diff --git a/tests/baselines/reference/numericIndexerConstraint4.types b/tests/baselines/reference/numericIndexerConstraint4.types
index 78b57d4179e..97e72b5088d 100644
--- a/tests/baselines/reference/numericIndexerConstraint4.types
+++ b/tests/baselines/reference/numericIndexerConstraint4.types
@@ -15,7 +15,7 @@ class B extends A {
 }
 
 var x: {
->x : { [x: number]: A; }
+>x : { [idx: number]: A; }
 
     [idx: number]: A;
 >idx : number
diff --git a/tests/baselines/reference/numericIndexerConstraint5.errors.txt b/tests/baselines/reference/numericIndexerConstraint5.errors.txt
index 445fc771218..98acc65eeb7 100644
--- a/tests/baselines/reference/numericIndexerConstraint5.errors.txt
+++ b/tests/baselines/reference/numericIndexerConstraint5.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/numericIndexerConstraint5.ts(2,5): error TS2322: Type '{ 0: Date; name: string; }' is not assignable to type '{ [x: number]: string; }'.
+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; }'.
 
 
@@ -6,5 +6,5 @@ tests/cases/compiler/numericIndexerConstraint5.ts(2,5): error TS2322: Type '{ 0:
     var x = { name: "x", 0: new Date() };
     var z: { [name: number]: string } = x;
         ~
-!!! error TS2322: Type '{ 0: Date; name: string; }' is not assignable to type '{ [x: number]: string; }'.
+!!! 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
diff --git a/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt b/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt
index ef084477f6d..c35e49f02a3 100644
--- a/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt
+++ b/tests/baselines/reference/objectLiteralIndexerErrors.errors.txt
@@ -1,4 +1,4 @@
-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 '{ [x: string]: A; [x: number]: B; }'.
+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.
     Type 'A' is not assignable to type 'B'.
 
@@ -18,7 +18,7 @@ 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 '{ [x: string]: A; [x: number]: B; }'.
+!!! 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 'A' is not assignable to type 'B'.
     o1 = { x: c, 0: a }; // string indexer is any, number indexer is A
\ No newline at end of file
diff --git a/tests/baselines/reference/objectLiteralIndexers.types b/tests/baselines/reference/objectLiteralIndexers.types
index 1dce9b94ada..d5add00ebaf 100644
--- a/tests/baselines/reference/objectLiteralIndexers.types
+++ b/tests/baselines/reference/objectLiteralIndexers.types
@@ -26,7 +26,7 @@ var c: any;
 >c : any
 
 var o1: { [s: string]: A;[n: number]: B; } = { x: a, 0: b }; // string indexer is A, number indexer is B
->o1 : { [x: string]: A; [x: number]: B; }
+>o1 : { [s: string]: A; [n: number]: B; }
 >s : string
 >A : A
 >n : number
@@ -38,7 +38,7 @@ var o1: { [s: string]: A;[n: number]: B; } = { x: a, 0: b }; // string indexer i
 
 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: string]: A; [x: number]: B; }
+>o1 : { [s: string]: A; [n: number]: B; }
 >{ x: b, 0: c } : { [x: string]: any; [x: number]: any; 0: any; x: B; }
 >x : B
 >b : B
@@ -46,7 +46,7 @@ o1 = { x: b, 0: c }; // both indexers are 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: string]: A; [x: number]: B; }
+>o1 : { [s: string]: A; [n: number]: B; }
 >{ x: c, 0: b } : { [x: string]: any; [x: number]: B; 0: B; x: any; }
 >x : any
 >c : any
diff --git a/tests/baselines/reference/parseShortform.types b/tests/baselines/reference/parseShortform.types
index 21aff67ead4..e9e3f68b559 100644
--- a/tests/baselines/reference/parseShortform.types
+++ b/tests/baselines/reference/parseShortform.types
@@ -3,7 +3,7 @@ interface I {
 >I : I
 
     w: {
->w : { (): boolean; [x: string]: { x: any; y: any; }; [x: number]: { x: any; y: any; }; z: I; }
+>w : { (): boolean; [s: string]: { x: any; y: any; }; [n: number]: { x: any; y: any; }; z: I; }
 
         z: I;
 >z : I
diff --git a/tests/baselines/reference/privatePropertyUsingObjectType.types b/tests/baselines/reference/privatePropertyUsingObjectType.types
index 678418b1ddf..4c6b6820fc0 100644
--- a/tests/baselines/reference/privatePropertyUsingObjectType.types
+++ b/tests/baselines/reference/privatePropertyUsingObjectType.types
@@ -8,7 +8,7 @@ export class FilterManager {
 >IFilterProvider : IFilterProvider
 
     private _filterProviders2: { [index: number]: IFilterProvider; };
->_filterProviders2 : { [x: number]: IFilterProvider; }
+>_filterProviders2 : { [index: number]: IFilterProvider; }
 >index : number
 >IFilterProvider : IFilterProvider
 
diff --git a/tests/baselines/reference/recursiveTypesWithTypeof.types b/tests/baselines/reference/recursiveTypesWithTypeof.types
index f75bae79c5b..14ff5a6d5b9 100644
--- a/tests/baselines/reference/recursiveTypesWithTypeof.types
+++ b/tests/baselines/reference/recursiveTypesWithTypeof.types
@@ -135,21 +135,21 @@ var j2 = new j2(j2);
 
 // Indexers
 var k: { [n: number]: typeof k;[s: string]: typeof k };
->k : { [x: string]: any; [x: number]: any; }
+>k : { [s: string]: any; [n: number]: any; }
 >n : number
->k : { [x: string]: any; [x: number]: any; }
+>k : { [s: string]: any; [n: number]: any; }
 >s : string
->k : { [x: string]: any; [x: number]: any; }
+>k : { [s: string]: any; [n: number]: any; }
 
 var k = k[0];
->k : { [x: string]: any; [x: number]: any; }
->k[0] : { [x: string]: any; [x: number]: any; }
->k : { [x: string]: any; [x: number]: any; }
+>k : { [s: string]: any; [n: number]: any; }
+>k[0] : { [s: string]: any; [n: number]: any; }
+>k : { [s: string]: any; [n: number]: any; }
 
 var k = k[''];
->k : { [x: string]: any; [x: number]: any; }
->k[''] : { [x: string]: any; [x: number]: any; }
->k : { [x: string]: any; [x: number]: any; }
+>k : { [s: string]: any; [n: number]: any; }
+>k[''] : { [s: string]: any; [n: number]: any; }
+>k : { [s: string]: any; [n: number]: any; }
 
 // Hybrid - contains type literals as well as type arguments
 // These two are recursive
diff --git a/tests/baselines/reference/stringIndexerAssignments1.errors.txt b/tests/baselines/reference/stringIndexerAssignments1.errors.txt
index 3939ceba1bb..908371bc7dd 100644
--- a/tests/baselines/reference/stringIndexerAssignments1.errors.txt
+++ b/tests/baselines/reference/stringIndexerAssignments1.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/compiler/stringIndexerAssignments1.ts(4,1): error TS2322: Type '{ one: string; }' is not assignable to type '{ [x: string]: string; one: string; }'.
+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 '{ [x: string]: string; 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'.
 
@@ -11,11 +11,11 @@ tests/cases/compiler/stringIndexerAssignments1.ts(5,1): error TS2322: Type '{ on
     var b: { one: number; two: string; };
     x = a;
     ~
-!!! error TS2322: Type '{ one: string; }' is not assignable to type '{ [x: string]: string; one: string; }'.
+!!! 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 '{ [x: string]: string; one: string; }'.
+!!! error TS2322: Type '{ one: number; two: string; }' is not assignable to type '{ [index: string]: string; one: string; }'.
 !!! error TS2322:   Types of property 'one' are incompatible.
 !!! error TS2322:     Type 'number' is not assignable to type 'string'.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/typeName1.errors.txt b/tests/baselines/reference/typeName1.errors.txt
index 64a32663875..84c8be360bd 100644
--- a/tests/baselines/reference/typeName1.errors.txt
+++ b/tests/baselines/reference/typeName1.errors.txt
@@ -10,7 +10,7 @@ tests/cases/compiler/typeName1.ts(13,5): error TS2322: Type 'number' is not assi
 tests/cases/compiler/typeName1.ts(14,5): error TS2322: Type 'number' is not assignable to type '{ z: number; f: { (n: number): string; (s: string): number; }; }'.
   Property 'z' is missing in type 'Number'.
 tests/cases/compiler/typeName1.ts(15,5): error TS2322: Type 'number' is not assignable to type '(s: string) => boolean'.
-tests/cases/compiler/typeName1.ts(16,5): error TS2322: Type 'number' is not assignable to type '{ (): boolean; [x: string]: { x: any; y: any; }; [x: number]: { x: any; y: any; }; z: I; }'.
+tests/cases/compiler/typeName1.ts(16,5): error TS2322: Type 'number' is not assignable to type '{ (): boolean; [s: string]: { x: any; y: any; }; [n: number]: { x: any; y: any; }; z: I; }'.
   Property 'z' is missing in type 'Number'.
 tests/cases/compiler/typeName1.ts(16,10): error TS2411: Property 'z' of type 'I' is not assignable to string index type '{ x: any; y: any; }'.
 tests/cases/compiler/typeName1.ts(17,5): error TS2322: Type 'number' is not assignable to type 'I'.
@@ -19,7 +19,7 @@ tests/cases/compiler/typeName1.ts(18,5): error TS2322: Type 'number' is not assi
   Property 'length' is missing in type 'Number'.
 tests/cases/compiler/typeName1.ts(19,5): error TS2322: Type 'number' is not assignable to type '{ z: I; x: boolean; }[][]'.
   Property 'length' is missing in type 'Number'.
-tests/cases/compiler/typeName1.ts(20,5): error TS2322: Type 'number' is not assignable to type '{ z: I; x: boolean; y: (s: string) => boolean; w: { (): boolean; [x: string]: { x: any; y: any; }; [x: number]: { x: any; y: any; }; z: I; }; }[][]'.
+tests/cases/compiler/typeName1.ts(20,5): error TS2322: Type 'number' is not assignable to type '{ z: I; x: boolean; y: (s: string) => boolean; w: { (): boolean; [s: string]: { x: any; y: any; }; [n: number]: { x: any; y: any; }; z: I; }; }[][]'.
   Property 'length' is missing in type 'Number'.
 tests/cases/compiler/typeName1.ts(20,50): error TS2411: Property 'z' of type 'I' is not assignable to string index type '{ x: any; y: any; }'.
 tests/cases/compiler/typeName1.ts(21,5): error TS2322: Type 'number' is not assignable to type '{ (): {}; new (): number; new (n: number): number; x: string; w: { y: number; }; }'.
@@ -66,7 +66,7 @@ tests/cases/compiler/typeName1.ts(23,5): error TS2322: Type 'typeof C' is not as
 !!! error TS2322: Type 'number' is not assignable to type '(s: string) => boolean'.
     var x8:{ z:I;[s:string]:{ x; y; };[n:number]:{x; y;};():boolean; }=3;
         ~~
-!!! error TS2322: Type 'number' is not assignable to type '{ (): boolean; [x: string]: { x: any; y: any; }; [x: number]: { x: any; y: any; }; z: I; }'.
+!!! error TS2322: Type 'number' is not assignable to type '{ (): boolean; [s: string]: { x: any; y: any; }; [n: number]: { x: any; y: any; }; z: I; }'.
 !!! error TS2322:   Property 'z' is missing in type 'Number'.
              ~~~~
 !!! error TS2411: Property 'z' of type 'I' is not assignable to string index type '{ x: any; y: any; }'.
@@ -84,7 +84,7 @@ tests/cases/compiler/typeName1.ts(23,5): error TS2322: Type 'typeof C' is not as
 !!! error TS2322:   Property 'length' is missing in type 'Number'.
     var x12:{z:I;x:boolean;y:(s:string)=>boolean;w:{ z:I;[s:string]:{ x; y; };[n:number]:{x; y;};():boolean; };}[][]=3;
         ~~~
-!!! error TS2322: Type 'number' is not assignable to type '{ z: I; x: boolean; y: (s: string) => boolean; w: { (): boolean; [x: string]: { x: any; y: any; }; [x: number]: { x: any; y: any; }; z: I; }; }[][]'.
+!!! error TS2322: Type 'number' is not assignable to type '{ z: I; x: boolean; y: (s: string) => boolean; w: { (): boolean; [s: string]: { x: any; y: any; }; [n: number]: { x: any; y: any; }; z: I; }; }[][]'.
 !!! error TS2322:   Property 'length' is missing in type 'Number'.
                                                      ~~~~
 !!! error TS2411: Property 'z' of type 'I' is not assignable to string index type '{ x: any; y: any; }'.
diff --git a/tests/baselines/reference/unionTypeIndexSignature.types b/tests/baselines/reference/unionTypeIndexSignature.types
index 96453cffcb4..4502a3ddfc3 100644
--- a/tests/baselines/reference/unionTypeIndexSignature.types
+++ b/tests/baselines/reference/unionTypeIndexSignature.types
@@ -10,7 +10,7 @@ var anyVar: number;
 // U has a string index signature of a union type of the types of the string index signatures from each type in U.
 
 var unionOfDifferentReturnType: { [a: string]: number; } | { [a: string]: Date; };
->unionOfDifferentReturnType : { [x: string]: number; } | { [x: string]: Date; }
+>unionOfDifferentReturnType : { [a: string]: number; } | { [a: string]: Date; }
 >a : string
 >a : string
 >Date : Date
@@ -19,34 +19,34 @@ numOrDate = unionOfDifferentReturnType["hello"]; // number | Date
 >numOrDate = unionOfDifferentReturnType["hello"] : number | Date
 >numOrDate : number | Date
 >unionOfDifferentReturnType["hello"] : number | Date
->unionOfDifferentReturnType : { [x: string]: number; } | { [x: string]: Date; }
+>unionOfDifferentReturnType : { [a: string]: number; } | { [a: string]: Date; }
 
 numOrDate = unionOfDifferentReturnType[10]; // number | Date
 >numOrDate = unionOfDifferentReturnType[10] : number | Date
 >numOrDate : number | Date
 >unionOfDifferentReturnType[10] : number | Date
->unionOfDifferentReturnType : { [x: string]: number; } | { [x: string]: Date; }
+>unionOfDifferentReturnType : { [a: string]: number; } | { [a: string]: Date; }
 
 var unionOfTypesWithAndWithoutStringSignature: { [a: string]: number; } | boolean;
->unionOfTypesWithAndWithoutStringSignature : boolean | { [x: string]: number; }
+>unionOfTypesWithAndWithoutStringSignature : boolean | { [a: string]: number; }
 >a : string
 
 anyVar = unionOfTypesWithAndWithoutStringSignature["hello"]; // any
 >anyVar = unionOfTypesWithAndWithoutStringSignature["hello"] : any
 >anyVar : number
 >unionOfTypesWithAndWithoutStringSignature["hello"] : any
->unionOfTypesWithAndWithoutStringSignature : boolean | { [x: string]: number; }
+>unionOfTypesWithAndWithoutStringSignature : boolean | { [a: string]: number; }
 
 anyVar = unionOfTypesWithAndWithoutStringSignature[10]; // any
 >anyVar = unionOfTypesWithAndWithoutStringSignature[10] : any
 >anyVar : number
 >unionOfTypesWithAndWithoutStringSignature[10] : any
->unionOfTypesWithAndWithoutStringSignature : boolean | { [x: string]: number; }
+>unionOfTypesWithAndWithoutStringSignature : boolean | { [a: string]: number; }
 
 // If each type in U has a numeric index signature, 
 // U has a numeric index signature of a union type of the types of the numeric index signatures from each type in U.
 var unionOfDifferentReturnType1: { [a: number]: number; } | { [a: number]: Date; };
->unionOfDifferentReturnType1 : { [x: number]: number; } | { [x: number]: Date; }
+>unionOfDifferentReturnType1 : { [a: number]: number; } | { [a: number]: Date; }
 >a : number
 >a : number
 >Date : Date
@@ -55,27 +55,27 @@ numOrDate = unionOfDifferentReturnType1["hello"]; // any
 >numOrDate = unionOfDifferentReturnType1["hello"] : any
 >numOrDate : number | Date
 >unionOfDifferentReturnType1["hello"] : any
->unionOfDifferentReturnType1 : { [x: number]: number; } | { [x: number]: Date; }
+>unionOfDifferentReturnType1 : { [a: number]: number; } | { [a: number]: Date; }
 
 numOrDate = unionOfDifferentReturnType1[10]; // number | Date
 >numOrDate = unionOfDifferentReturnType1[10] : number | Date
 >numOrDate : number | Date
 >unionOfDifferentReturnType1[10] : number | Date
->unionOfDifferentReturnType1 : { [x: number]: number; } | { [x: number]: Date; }
+>unionOfDifferentReturnType1 : { [a: number]: number; } | { [a: number]: Date; }
 
 var unionOfTypesWithAndWithoutStringSignature1: { [a: number]: number; } | boolean;
->unionOfTypesWithAndWithoutStringSignature1 : boolean | { [x: number]: number; }
+>unionOfTypesWithAndWithoutStringSignature1 : boolean | { [a: number]: number; }
 >a : number
 
 anyVar = unionOfTypesWithAndWithoutStringSignature1["hello"]; // any
 >anyVar = unionOfTypesWithAndWithoutStringSignature1["hello"] : any
 >anyVar : number
 >unionOfTypesWithAndWithoutStringSignature1["hello"] : any
->unionOfTypesWithAndWithoutStringSignature1 : boolean | { [x: number]: number; }
+>unionOfTypesWithAndWithoutStringSignature1 : boolean | { [a: number]: number; }
 
 anyVar = unionOfTypesWithAndWithoutStringSignature1[10]; // any
 >anyVar = unionOfTypesWithAndWithoutStringSignature1[10] : any
 >anyVar : number
 >unionOfTypesWithAndWithoutStringSignature1[10] : any
->unionOfTypesWithAndWithoutStringSignature1 : boolean | { [x: number]: number; }
+>unionOfTypesWithAndWithoutStringSignature1 : boolean | { [a: number]: number; }
 
diff --git a/tests/baselines/reference/vardecl.types b/tests/baselines/reference/vardecl.types
index 25257e57d78..d6847dc3be7 100644
--- a/tests/baselines/reference/vardecl.types
+++ b/tests/baselines/reference/vardecl.types
@@ -52,7 +52,7 @@ complicatedArrayVar.push({ x: 30, y : 'hello world' });
 >y : string
 
 var n1: { [s: string]: number; };
->n1 : { [x: string]: number; }
+>n1 : { [s: string]: number; }
 >s : string
 
 var c : {