merge with master, accepted baselines

src/compiler/types.ts

@@ -1491,11 +1491,15 @@ module ts {
         (t: Type): Type;
     }
 
+    // @internal
     export interface TypeInferences {
         primary: Type[];    // Inferences made directly to a type parameter
         secondary: Type[];  // Inferences made to a type parameter in a union type
+        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
         inferUnionTypes: boolean;           // Infer union types for disjoint candidates (otherwise undefinedType)