Emit pinned/tripleslash reference comments of elided module declaration

Fixes #501

Author: sheetalkamat

src/compiler/emitter.ts

@@ -1761,7 +1761,10 @@ module ts {
             }
 
             function emitModuleDeclaration(node: ModuleDeclaration) {
-                if (!isInstantiated(node)) return;
+                if (!isInstantiated(node)) {
+                    return emitPinnedOrTripleSlashComments(node);
+                }
+
                 emitLeadingComments(node);
                 if (!(node.flags & NodeFlags.Export)) {
                     emitStart(node);

tests/baselines/reference/commentOnElidedModule1.js

@@ -1,10 +1,20 @@
-//// [commentOnElidedModule1.ts]
+//// [tests/cases/compiler/commentOnElidedModule1.ts] ////
+
+//// [a.ts]
 /*! Keep this pinned comment */
 module ElidedModule {
 }
 
 // Don't keep this comment.
 module ElidedModule2 {
+}
+
+//// [b.ts]
+///<reference path="a.ts"/>
+module ElidedModule3 {
 }
 
-//// [commentOnElidedModule1.js]
+//// [a.js]
+/*! Keep this pinned comment */
+//// [b.js]
+///<reference path="a.ts"/>

tests/baselines/reference/commentOnElidedModule1.types

@@ -1,4 +1,9 @@
-=== tests/cases/compiler/commentOnElidedModule1.ts ===
+=== tests/cases/compiler/b.ts ===
+///<reference path="a.ts"/>
+module ElidedModule3 {
+>ElidedModule3 : ElidedModule3
+}
+=== tests/cases/compiler/a.ts ===
 /*! Keep this pinned comment */
 module ElidedModule {
 >ElidedModule : ElidedModule
@@ -8,3 +13,4 @@ module ElidedModule {
 module ElidedModule2 {
 >ElidedModule2 : ElidedModule2
 }
+

tests/cases/compiler/commentOnElidedModule1.ts

@@ -1,7 +1,13 @@
+//@filename: a.ts
 /*! Keep this pinned comment */
 module ElidedModule {
 }
 
 // Don't keep this comment.
 module ElidedModule2 {
+}
+
+//@filename: b.ts
+///<reference path="a.ts"/>
+module ElidedModule3 {
 }