Correct the external module check to determine if declaration is part of export assignment

Author: sheetalkamat

src/compiler/emitter.ts

@@ -1891,7 +1891,10 @@ module ts {
             }
 
             // If this node is in external module, check if this is export assigned 
-            if (getContainerOfModuleElementDeclaration(node).flags & NodeFlags.ExternalModule) {
+            var moduleDeclaration = getContainerOfModuleElementDeclaration(node);
+            if ((moduleDeclaration.flags & NodeFlags.ExternalModule) || // Source file with external module flag
+                // Ambient external module declaration
+                (moduleDeclaration.kind === SyntaxKind.ModuleDeclaration && (<ModuleDeclaration>moduleDeclaration).name.kind === SyntaxKind.StringLiteral)) {
                 return resolver.isReferencedInExportAssignment(node);
             }
 
@@ -2083,6 +2086,7 @@ module ts {
         }
 
         function emitVariableDeclaration(node: VariableDeclaration) {
+            // If we are emitting property it isnt moduleElement and doesnt need canEmitModuleElement check
             if (node.kind !== SyntaxKind.VariableDeclaration || canEmitModuleElementDeclaration(node)) {
                 emitSourceTextOfNode(node.name);
                 // If optional property emit ?

src/compiler/parser.ts

@@ -275,7 +275,8 @@ module ts {
 
     export function getContainerOfModuleElementDeclaration(node: Declaration) {
         // If the declaration is var declaration, then the parent is variable statement but we actually want the module
-        return node.kind === SyntaxKind.VariableDeclaration ? node.parent.parent : node.parent;
+        var container = node.kind === SyntaxKind.VariableDeclaration ? node.parent.parent : node.parent;
+        return container.kind == SyntaxKind.ModuleBlock ? container.parent : container;
     }
 
     enum ParsingContext {

tests/baselines/reference/missingImportAfterModuleImport.js

@@ -35,6 +35,11 @@ module.exports = MainModule;
 
 //// [missingImportAfterModuleImport_0.d.ts]
 declare module "SubModule" {
+    class SubModule {
+        static StaticVar;
+        InstanceVar;
+        constructor ();
+    }
     export = SubModule;
 }
 //// [missingImportAfterModuleImport_1.d.ts]