Address PR

Author: Yui T

src/compiler/declarationEmitter.ts

@@ -341,7 +341,7 @@ namespace ts {
             }
             else {
                 errorNameNode = signature.name;
-                resolver.writeReturnTypeOfSignatureDeclaration(signature, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction, writer);
+                resolver.writeReturnTypeOfSignatureDeclaration(signature, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction | TypeFormatFlags.UseTypeAliasValue, writer);
                 errorNameNode = undefined;
             }
         }
@@ -563,7 +563,7 @@ namespace ts {
                 write(tempVarName);
                 write(": ");
                 writer.getSymbolAccessibilityDiagnostic = getDefaultExportAccessibilityDiagnostic;
-                resolver.writeTypeOfExpression(node.expression, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction, writer);
+                resolver.writeTypeOfExpression(node.expression, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction | TypeFormatFlags.UseTypeAliasValue, writer);
                 write(";");
                 writeLine();
                 write(node.isExportEquals ? "export = " : "export default ");
@@ -1025,7 +1025,7 @@ namespace ts {
                 }
                 else {
                     writer.getSymbolAccessibilityDiagnostic = getHeritageClauseVisibilityError;
-                    resolver.writeBaseConstructorTypeOfClass(<ClassLikeDeclaration>enclosingDeclaration, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction, writer);
+                    resolver.writeBaseConstructorTypeOfClass(<ClassLikeDeclaration>enclosingDeclaration, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction | TypeFormatFlags.UseTypeAliasValue, writer);
                 }
 
                 function getHeritageClauseVisibilityError(symbolAccessibilityResult: SymbolAccessibilityResult): SymbolAccessibilityDiagnostic {

src/compiler/types.ts

@@ -1946,7 +1946,7 @@ namespace ts {
         UseFullyQualifiedType           = 0x00000080,  // Write out the fully qualified type name (eg. Module.Type, instead of Type)
         InFirstTypeArgument             = 0x00000100,  // Writing first type argument of the instantiated type
         InTypeAlias                     = 0x00000200,  // Writing type in type alias declaration
-        UseTypeAliasValue               = 0x00000400,  // Writing infered type alias as its value. This is used when we emit declaration file
+        UseTypeAliasValue               = 0x00000400,  // Serialize the type instead of using type-alias. This is needed when we emit declaration file.
     }
 
     export const enum SymbolFormatFlags {