diff --git a/tests/baselines/reference/indexSignatureTypeCheck.errors.txt b/tests/baselines/reference/indexSignatureTypeCheck.errors.txt
index 20890f3e13156..1931b5bd7dded 100644
--- a/tests/baselines/reference/indexSignatureTypeCheck.errors.txt
+++ b/tests/baselines/reference/indexSignatureTypeCheck.errors.txt
@@ -1,21 +1,21 @@
-tests/cases/compiler/indexSignatureTypeCheck.ts(35,1): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
-tests/cases/compiler/indexSignatureTypeCheck.ts(38,8): error TS1019: An index signature parameter cannot have a question mark.
-tests/cases/compiler/indexSignatureTypeCheck.ts(39,6): error TS1017: An index signature cannot have a rest parameter.
+tests/cases/compiler/indexSignatureTypeCheck.ts(34,1): error TS2342: An index expression argument must be of type 'string', 'number', 'symbol, or 'any'.
+tests/cases/compiler/indexSignatureTypeCheck.ts(37,8): error TS1019: An index signature parameter cannot have a question mark.
+tests/cases/compiler/indexSignatureTypeCheck.ts(38,6): error TS1017: An index signature cannot have a rest parameter.
+tests/cases/compiler/indexSignatureTypeCheck.ts(39,6): error TS1096: An index signature must have exactly one parameter.
 tests/cases/compiler/indexSignatureTypeCheck.ts(40,6): error TS1096: An index signature must have exactly one parameter.
-tests/cases/compiler/indexSignatureTypeCheck.ts(41,6): error TS1096: An index signature must have exactly one parameter.
-tests/cases/compiler/indexSignatureTypeCheck.ts(51,2): error TS2375: Duplicate number index signature.
-tests/cases/compiler/indexSignatureTypeCheck.ts(56,2): error TS2375: Duplicate number index signature.
-tests/cases/compiler/indexSignatureTypeCheck.ts(64,1): error TS2322: Type '{ [x: number]: string; }' is not assignable to type '{ [x: string]: string; }'.
+tests/cases/compiler/indexSignatureTypeCheck.ts(50,5): error TS2375: Duplicate number index signature.
+tests/cases/compiler/indexSignatureTypeCheck.ts(55,5): error TS2375: Duplicate number index signature.
+tests/cases/compiler/indexSignatureTypeCheck.ts(65,1): 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/indexSignatureTypeCheck.ts(65,1): error TS2322: Type '{ [x: number]: number; }' is not assignable to type '{ [x: string]: string; }'.
+tests/cases/compiler/indexSignatureTypeCheck.ts(66,1): error TS2322: Type '{ [x: number]: number; }' is not assignable to type '{ [x: string]: string; }'.
   Index signature is missing in type '{ [x: number]: number; }'.
-tests/cases/compiler/indexSignatureTypeCheck.ts(69,1): error TS2322: Type '{ [x: number]: number; }' is not assignable to type '{ [x: number]: string; }'.
+tests/cases/compiler/indexSignatureTypeCheck.ts(70,1): error TS2322: Type '{ [x: number]: number; }' is not assignable to type '{ [x: number]: string; }'.
   Index signatures are incompatible.
     Type 'number' is not assignable to type 'string'.
-tests/cases/compiler/indexSignatureTypeCheck.ts(71,1): error TS2322: Type '{ [x: string]: string; }' is not assignable to type '{ [x: number]: number; }'.
+tests/cases/compiler/indexSignatureTypeCheck.ts(72,1): error TS2322: Type '{ [x: string]: string; }' is not assignable to type '{ [x: number]: number; }'.
   Index signatures are incompatible.
     Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/indexSignatureTypeCheck.ts(72,1): error TS2322: Type '{ [x: number]: string; }' is not assignable to type '{ [x: number]: number; }'.
+tests/cases/compiler/indexSignatureTypeCheck.ts(73,1): error TS2322: Type '{ [x: number]: string; }' is not assignable to type '{ [x: number]: number; }'.
   Index signatures are incompatible.
     Type 'string' is not assignable to type 'number'.
 
@@ -29,31 +29,30 @@ tests/cases/compiler/indexSignatureTypeCheck.ts(72,1): error TS2322: Type '{ [x:
     var index: any = "hello";
     ps[index] = 12;
     
-    enum Val {
+    enum Values {
         a = 1,
         b = 2
     }
     
-    type Val2 = Val;
-    type Val3 = number;
+    type Values2 = Values;
+    type Values3 = number;
      
-    interface IEnum {
-        [index: Val]: Val;
+    interface EnumMap {
+        [index: Values]: Values;
     }
     
-    
-    interface IEnum2 {
-        [index: Val2]: Val2;
+    interface EnumMap2 {
+        [index: Values2]: Values2;
     }
-    interface IEnum3 {
-        [index: Val3]: Val3;
+    interface NumberMap {
+        [index: Values3]: Values3;
     }
     
-    var pe: IEnum = null;
+    var pe: Values = null;
     
     pe[1] = null
     pe[3] = null
-    pe[Val.b] = 5
+    pe[Values.b] = 5
     
     pe[true] = null
     ~~~~~~~~
@@ -80,21 +79,23 @@ tests/cases/compiler/indexSignatureTypeCheck.ts(72,1): error TS2322: Type '{ [x:
     
     
     interface DuplicateAccess {
-    	[index: Val]: Val;
-    	[index: Val2]: Val2;
-    	~~~~~~~~~~~~~~~~~~~~
+        [index: Values]: Values;
+        [index: Values2]: Values2;
+        ~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2375: Duplicate number index signature.
     }
     
     interface DuplicateAccess2 {
-    	[index: number]: Val;
-    	[index: Val3]: Val3;
-    	~~~~~~~~~~~~~~~~~~~~
+        [index: number]: Values;
+        [index: Values3]: Values3;
+        ~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2375: Duplicate number index signature.
     }
     
     var x: { [x: string]: string }
+    var xn: {[x: string]: number }
     var y: { [x: number]: string }
+    var yn: { [x: number]: number }
     var z: { [x: E]: number }
     
     x = x;
@@ -126,5 +127,14 @@ tests/cases/compiler/indexSignatureTypeCheck.ts(72,1): error TS2322: Type '{ [x:
 !!! error TS2322:   Index signatures are incompatible.
 !!! error TS2322:     Type 'string' is not assignable to type 'number'.
     z = z;
+    z = yn;
+    z = xn;
+    
+    // TODO: Should fail
+    yn = z;
     
+    type foo = string
+    var s: { [x: foo]: string }
+    x = s
+    s = x
     
\ No newline at end of file
diff --git a/tests/baselines/reference/indexSignatureTypeCheck.js b/tests/baselines/reference/indexSignatureTypeCheck.js
index b1c8d075919a6..f373336dba7aa 100644
--- a/tests/baselines/reference/indexSignatureTypeCheck.js
+++ b/tests/baselines/reference/indexSignatureTypeCheck.js
@@ -7,31 +7,30 @@ var ps: IPropertySet = null;
 var index: any = "hello";
 ps[index] = 12;
 
-enum Val {
+enum Values {
     a = 1,
     b = 2
 }
 
-type Val2 = Val;
-type Val3 = number;
+type Values2 = Values;
+type Values3 = number;
  
-interface IEnum {
-    [index: Val]: Val;
+interface EnumMap {
+    [index: Values]: Values;
 }
 
-
-interface IEnum2 {
-    [index: Val2]: Val2;
+interface EnumMap2 {
+    [index: Values2]: Values2;
 }
-interface IEnum3 {
-    [index: Val3]: Val3;
+interface NumberMap {
+    [index: Values3]: Values3;
 }
 
-var pe: IEnum = null;
+var pe: Values = null;
 
 pe[1] = null
 pe[3] = null
-pe[Val.b] = 5
+pe[Values.b] = 5
 
 pe[true] = null
 
@@ -48,17 +47,19 @@ enum E {
 
 
 interface DuplicateAccess {
-	[index: Val]: Val;
-	[index: Val2]: Val2;
+    [index: Values]: Values;
+    [index: Values2]: Values2;
 }
 
 interface DuplicateAccess2 {
-	[index: number]: Val;
-	[index: Val3]: Val3;
+    [index: number]: Values;
+    [index: Values3]: Values3;
 }
 
 var x: { [x: string]: string }
+var xn: {[x: string]: number }
 var y: { [x: number]: string }
+var yn: { [x: number]: number }
 var z: { [x: E]: number }
 
 x = x;
@@ -72,22 +73,31 @@ y = z;
 z = x;
 z = y;
 z = z;
+z = yn;
+z = xn;
+
+// TODO: Should fail
+yn = z;
 
+type foo = string
+var s: { [x: foo]: string }
+x = s
+s = x
 
 
 //// [indexSignatureTypeCheck.js]
 var ps = null;
 var index = "hello";
 ps[index] = 12;
-var Val;
-(function (Val) {
-    Val[Val["a"] = 1] = "a";
-    Val[Val["b"] = 2] = "b";
-})(Val || (Val = {}));
+var Values;
+(function (Values) {
+    Values[Values["a"] = 1] = "a";
+    Values[Values["b"] = 2] = "b";
+})(Values || (Values = {}));
 var pe = null;
 pe[1] = null;
 pe[3] = null;
-pe[Val.b] = 5;
+pe[Values.b] = 5;
 pe[true] = null;
 var E;
 (function (E) {
@@ -96,7 +106,9 @@ var E;
     E[E["C"] = 2] = "C";
 })(E || (E = {}));
 var x;
+var xn;
 var y;
+var yn;
 var z;
 x = x;
 x = y;
@@ -107,3 +119,10 @@ y = z;
 z = x;
 z = y;
 z = z;
+z = yn;
+z = xn;
+// TODO: Should fail
+yn = z;
+var s;
+x = s;
+s = x;
diff --git a/tests/cases/compiler/indexSignatureTypeCheck.ts b/tests/cases/compiler/indexSignatureTypeCheck.ts
index 6ed2dc51e6001..57f479b728e9d 100644
--- a/tests/cases/compiler/indexSignatureTypeCheck.ts
+++ b/tests/cases/compiler/indexSignatureTypeCheck.ts
@@ -56,7 +56,9 @@ interface DuplicateAccess2 {
 }
 
 var x: { [x: string]: string }
+var xn: {[x: string]: number }
 var y: { [x: number]: string }
+var yn: { [x: number]: number }
 var z: { [x: E]: number }
 
 x = x;
@@ -70,7 +72,11 @@ y = z;
 z = x;
 z = y;
 z = z;
+z = yn;
+z = xn;
 
+// TODO: Should fail
+yn = z;
 
 type foo = string
 var s: { [x: foo]: string }