Always use literal types

src/compiler/binder.ts

@@ -591,6 +591,9 @@ namespace ts {
                 case SyntaxKind.PrefixUnaryExpression:
                     bindPrefixUnaryExpressionFlow(<PrefixUnaryExpression>node);
                     break;
+                case SyntaxKind.PostfixUnaryExpression:
+                    bindPostfixUnaryExpressionFlow(<PostfixUnaryExpression>node);
+                    break;
                 case SyntaxKind.BinaryExpression:
                     bindBinaryExpressionFlow(<BinaryExpression>node);
                     break;
@@ -1106,6 +1109,16 @@ namespace ts {
             }
             else {
                 forEachChild(node, bind);
+                if (node.operator === SyntaxKind.PlusEqualsToken || node.operator === SyntaxKind.MinusMinusToken) {
+                    bindAssignmentTargetFlow(node.operand);
+                }
+            }
+        }
+
+        function bindPostfixUnaryExpressionFlow(node: PostfixUnaryExpression) {
+            forEachChild(node, bind);
+            if (node.operator === SyntaxKind.PlusPlusToken || node.operator === SyntaxKind.MinusMinusToken) {
+                bindAssignmentTargetFlow(node.operand);
             }
         }
 

src/compiler/diagnosticMessages.json

@@ -1063,10 +1063,6 @@
         "category": "Error",
         "code": 2353
     },
-    "No best common type exists among return expressions.": {
-        "category": "Error",
-        "code": 2354
-    },
     "A function whose declared type is neither 'void' nor 'any' must return a value.": {
         "category": "Error",
         "code": 2355
@@ -1631,10 +1627,6 @@
         "category": "Error",
         "code": 2503
     },
-    "No best common type exists among yield expressions.": {
-        "category": "Error",
-        "code": 2504
-    },
     "A generator cannot have a 'void' type annotation.": {
         "category": "Error",
         "code": 2505

src/compiler/types.ts

@@ -2593,13 +2593,14 @@ namespace ts {
     export interface TypeInferences {
         primary: Type[];    // Inferences made directly to a type parameter
         secondary: Type[];  // Inferences made to a type parameter in a union type
+        topLevel: boolean;  // True if all inferences were made from top-level (not nested in object type) locations
         isFixed: boolean;   // Whether the type parameter is fixed, as defined in section 4.12.2 of the TypeScript spec
                             // If a type parameter is fixed, no more inferences can be made for the type parameter
     }
 
     /* @internal */
     export interface InferenceContext {
-        typeParameters: TypeParameter[];    // Type parameters for which inferences are made
+        signature: Signature;               // Generic signature for which inferences are made
         inferUnionTypes: boolean;           // Infer union types for disjoint candidates (otherwise undefinedType)
         inferences: TypeInferences[];       // Inferences made for each type parameter
         inferredTypes: Type[];              // Inferred type for each type parameter

tests/baselines/reference/AmbientModuleAndAmbientWithSameNameAndCommonRoot.types

@@ -56,6 +56,6 @@ var p = new A.Point(0, 0); // unexpected error here, bug 840000
 >A.Point : typeof A.Point
 >A : typeof A
 >Point : typeof A.Point
->0 : number
->0 : number
+>0 : 0
+>0 : 0
 

tests/baselines/reference/AmbientModuleAndNonAmbientClassWithSameNameAndCommonRoot.types

@@ -50,6 +50,6 @@ var p = new A.Point(0, 0); // unexpected error here, bug 840000
 >A.Point : typeof A.Point
 >A : typeof A
 >Point : typeof A.Point
->0 : number
->0 : number
+>0 : 0
+>0 : 0
 

tests/baselines/reference/AmbientModuleAndNonAmbientFunctionWithTheSameNameAndCommonRoot.types

@@ -15,9 +15,9 @@ function Point() {
     return { x: 0, y: 0 };
 >{ x: 0, y: 0 } : { x: number; y: number; }
 >x : number
->0 : number
+>0 : 0
 >y : number
->0 : number
+>0 : 0
 }
 
 === tests/cases/conformance/internalModules/DeclarationMerging/test.ts ===

tests/baselines/reference/ClassAndModuleThatMergeWithStaticFunctionAndNonExportedFunctionThatShareAName.types

@@ -11,17 +11,17 @@ class Point {
 >Point : Point
 >{ x: 0, y: 0 } : { x: number; y: number; }
 >x : number
->0 : number
+>0 : 0
 >y : number
->0 : number
+>0 : 0
 }
 
 module Point {
 >Point : typeof Point
 
     function Origin() { return ""; }// not an error, since not exported
 >Origin : () => string
->"" : string
+>"" : ""
 }
 
 
@@ -40,16 +40,16 @@ module A {
 >Point : Point
 >{ x: 0, y: 0 } : { x: number; y: number; }
 >x : number
->0 : number
+>0 : 0
 >y : number
->0 : number
+>0 : 0
     }
 
     export module Point {
 >Point : typeof Point
 
         function Origin() { return ""; }// not an error since not exported
 >Origin : () => string
->"" : string
+>"" : ""
     }
 }

tests/baselines/reference/ClassAndModuleThatMergeWithStaticVariableAndNonExportedVarThatShareAName.types

@@ -11,17 +11,17 @@ class Point {
 >Point : Point
 >{ x: 0, y: 0 } : { x: number; y: number; }
 >x : number
->0 : number
+>0 : 0
 >y : number
->0 : number
+>0 : 0
 }
 
 module Point {
 >Point : typeof Point
 
     var Origin = ""; // not an error, since not exported
 >Origin : string
->"" : string
+>"" : ""
 }
 
 
@@ -40,16 +40,16 @@ module A {
 >Point : Point
 >{ x: 0, y: 0 } : { x: number; y: number; }
 >x : number
->0 : number
+>0 : 0
 >y : number
->0 : number
+>0 : 0
     }
 
     export module Point {
 >Point : typeof Point
 
         var Origin = ""; // not an error since not exported
 >Origin : string
->"" : string
+>"" : ""
     }
 }

tests/baselines/reference/ClassDeclarationWithInvalidConstOnPropertyDeclaration2.types

@@ -7,5 +7,5 @@ class C {
 
     x = 10;
 >x : number
->10 : number
+>10 : 10
 }

tests/baselines/reference/ES3For-ofTypeCheck2.types

@@ -2,5 +2,5 @@
 for (var v of [true]) { }
 >v : boolean
 >[true] : boolean[]
->true : boolean
+>true : true
 

tests/baselines/reference/ES5For-of10.types

@@ -5,7 +5,7 @@ function foo() {
     return { x: 0 };
 >{ x: 0 } : { x: number; }
 >x : number
->0 : number
+>0 : 0
 }
 for (foo().x of []) {
 >foo().x : number

tests/baselines/reference/ES5For-of13.types

@@ -2,9 +2,9 @@
 for (let v of ['a', 'b', 'c']) {
 >v : string
 >['a', 'b', 'c'] : string[]
->'a' : string
->'b' : string
->'c' : string
+>'a' : "a"
+>'b' : "b"
+>'c' : "c"
 
     var x = v;
 >x : string

tests/baselines/reference/ES5For-of24.types

@@ -2,15 +2,15 @@
 var a = [1, 2, 3];
 >a : number[]
 >[1, 2, 3] : number[]
->1 : number
->2 : number
->3 : number
+>1 : 1
+>2 : 2
+>3 : 3
 
 for (var v of a) {
 >v : number
 >a : number[]
 
     let a = 0;
 >a : number
->0 : number
+>0 : 0
 }

tests/baselines/reference/ES5For-of25.types

@@ -2,9 +2,9 @@
 var a = [1, 2, 3];
 >a : number[]
 >[1, 2, 3] : number[]
->1 : number
->2 : number
->3 : number
+>1 : 1
+>2 : 2
+>3 : 3
 
 for (var v of a) {
 >v : number

tests/baselines/reference/ES5For-of3.types

@@ -2,9 +2,9 @@
 for (var v of ['a', 'b', 'c'])
 >v : string
 >['a', 'b', 'c'] : string[]
->'a' : string
->'b' : string
->'c' : string
+>'a' : "a"
+>'b' : "b"
+>'c' : "c"
 
     var x = v;
 >x : string

tests/baselines/reference/ES5For-of30.errors.txt

@@ -1,6 +1,6 @@
 tests/cases/conformance/statements/for-ofStatements/ES5For-of30.ts(3,6): error TS2461: Type 'string | number' is not an array type.
-tests/cases/conformance/statements/for-ofStatements/ES5For-of30.ts(3,7): error TS2322: Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/statements/for-ofStatements/ES5For-of30.ts(3,14): error TS2322: Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of30.ts(3,7): error TS2322: Type '1' is not assignable to type 'string'.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of30.ts(3,14): error TS2322: Type '""' is not assignable to type 'number'.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-of30.ts (3 errors) ====
@@ -10,9 +10,9 @@ tests/cases/conformance/statements/for-ofStatements/ES5For-of30.ts(3,14): error
          ~~~~~~~~~~~~~~~
 !!! error TS2461: Type 'string | number' is not an array type.
           ~
-!!! error TS2322: Type 'number' is not assignable to type 'string'.
+!!! error TS2322: Type '1' is not assignable to type 'string'.
                  ~
-!!! error TS2322: Type 'string' is not assignable to type 'number'.
+!!! error TS2322: Type '""' is not assignable to type 'number'.
         a;
         b;
     }

tests/baselines/reference/ES5For-of9.types

@@ -5,7 +5,7 @@ function foo() {
     return { x: 0 };
 >{ x: 0 } : { x: number; }
 >x : number
->0 : number
+>0 : 0
 }
 for (foo().x of []) {
 >foo().x : number

tests/baselines/reference/ES5For-ofTypeCheck1.types

@@ -1,5 +1,5 @@
 === tests/cases/conformance/statements/for-ofStatements/ES5For-ofTypeCheck1.ts ===
 for (var v of "") { }
 >v : string
->"" : string
+>"" : ""
 

tests/baselines/reference/ES5For-ofTypeCheck12.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/statements/for-ofStatements/ES5For-ofTypeCheck12.ts(1,17): error TS2495: Type 'number' is not an array type or a string type.
+tests/cases/conformance/statements/for-ofStatements/ES5For-ofTypeCheck12.ts(1,17): error TS2495: Type '0' is not an array type or a string type.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-ofTypeCheck12.ts (1 errors) ====
     for (const v of 0) { }
                     ~
-!!! error TS2495: Type 'number' is not an array type or a string type.
+!!! error TS2495: Type '0' is not an array type or a string type.

tests/baselines/reference/ES5For-ofTypeCheck2.types

@@ -2,5 +2,5 @@
 for (var v of [true]) { }
 >v : boolean
 >[true] : boolean[]
->true : boolean
+>true : true
 

tests/baselines/reference/ES5For-ofTypeCheck3.types

@@ -2,8 +2,8 @@
 var tuple: [string, number] = ["", 0];
 >tuple : [string, number]
 >["", 0] : [string, number]
->"" : string
->0 : number
+>"" : ""
+>0 : 0
 
 for (var v of tuple) { }
 >v : string | number

tests/baselines/reference/ES5for-of32.types

@@ -3,13 +3,13 @@
 var array = [1,2,3];
 >array : number[]
 >[1,2,3] : number[]
->1 : number
->2 : number
->3 : number
+>1 : 1
+>2 : 2
+>3 : 3
 
 var sum = 0;
 >sum : number
->0 : number
+>0 : 0
 
 for (let num of array) {
 >num : number
@@ -24,9 +24,9 @@ for (let num of array) {
 >array = [4,5,6] : number[]
 >array : number[]
 >[4,5,6] : number[]
->4 : number
->5 : number
->6 : number
+>4 : 4
+>5 : 5
+>6 : 6
     }
 
     sum += num;

tests/baselines/reference/EnumAndModuleWithSameNameAndCommonRoot.types

@@ -3,8 +3,8 @@ enum enumdule {
 >enumdule : enumdule
 
     Red, Blue
->Red : enumdule
->Blue : enumdule
+>Red : enumdule.Red
+>Blue : enumdule.Blue
 }
 
 module enumdule {
@@ -25,9 +25,9 @@ var x: enumdule;
 
 var x = enumdule.Red;
 >x : enumdule
->enumdule.Red : enumdule
+>enumdule.Red : enumdule.Red
 >enumdule : typeof enumdule
->Red : enumdule
+>Red : enumdule.Red
 
 var y: { x: number; y: number };
 >y : { x: number; y: number; }
@@ -40,6 +40,6 @@ var y = new enumdule.Point(0, 0);
 >enumdule.Point : typeof enumdule.Point
 >enumdule : typeof enumdule
 >Point : typeof enumdule.Point
->0 : number
->0 : number
+>0 : 0
+>0 : 0
 

tests/baselines/reference/ExportClassWhichExtendsInterfaceWithInaccessibleType.types

@@ -31,7 +31,7 @@ module A {
 >Point : Point
 
             return 1;
->1 : number
+>1 : 1
         }
     }
 }