Fix the incorrect eliding of import declaration

src/compiler/checker.ts

@@ -4474,7 +4474,7 @@ module ts {
             if (symbol.flags & SymbolFlags.Import) {
                 // Mark the import as referenced so that we emit it in the final .js file.
                 // exception: identifiers that appear in type queries, const enums, modules that contain only const enums
-                getSymbolLinks(symbol).referenced = !isInTypeQuery(node) && !isConstEnumOrConstEnumOnlyModule(resolveImport(symbol));
+                getSymbolLinks(symbol).referenced = getSymbolLinks(symbol).referenced || (!isInTypeQuery(node) && !isConstEnumOrConstEnumOnlyModule(resolveImport(symbol)));
             }
 
             checkCollisionWithCapturedSuperVariable(node, node);

tests/baselines/reference/aliasUsageInIndexerOfClass.js

@@ -50,6 +50,7 @@ var VisualizationModel = (function (_super) {
 })(Backbone.Model);
 exports.VisualizationModel = VisualizationModel;
 //// [aliasUsageInIndexerOfClass_main.js]
+var moduleA = require("aliasUsageInIndexerOfClass_moduleA");
 var N = (function () {
     function N() {
         this.x = moduleA;

tests/baselines/reference/elidingImportNames.js

@@ -0,0 +1,27 @@
+//// [tests/cases/compiler/elidingImportNames.ts] ////
+
+//// [elidingImportNames_test.ts]
+
+import a = require('elidingImportNames_main'); // alias used in typeof
+var b = a;
+var x: typeof a;
+import a2 = require('elidingImportNames_main1'); // alias not used in typeof
+var b2 = a2;
+
+
+//// [elidingImportNames_main.ts]
+export var main = 10;
+
+//// [elidingImportNames_main1.ts]
+export var main = 10;
+
+//// [elidingImportNames_main.js]
+exports.main = 10;
+//// [elidingImportNames_main1.js]
+exports.main = 10;
+//// [elidingImportNames_test.js]
+var a = require('elidingImportNames_main'); // alias used in typeof
+var b = a;
+var x;
+var a2 = require('elidingImportNames_main1'); // alias not used in typeof
+var b2 = a2;

tests/baselines/reference/elidingImportNames.types

@@ -0,0 +1,29 @@
+=== tests/cases/compiler/elidingImportNames_test.ts ===
+
+import a = require('elidingImportNames_main'); // alias used in typeof
+>a : typeof a
+
+var b = a;
+>b : typeof a
+>a : typeof a
+
+var x: typeof a;
+>x : typeof a
+>a : typeof a
+
+import a2 = require('elidingImportNames_main1'); // alias not used in typeof
+>a2 : typeof a2
+
+var b2 = a2;
+>b2 : typeof a2
+>a2 : typeof a2
+
+
+=== tests/cases/compiler/elidingImportNames_main.ts ===
+export var main = 10;
+>main : number
+
+=== tests/cases/compiler/elidingImportNames_main1.ts ===
+export var main = 10;
+>main : number
+

tests/cases/compiler/elidingImportNames.ts

@@ -0,0 +1,15 @@
+// @module: commonjs
+
+// @Filename: elidingImportNames_test.ts
+import a = require('elidingImportNames_main'); // alias used in typeof
+var b = a;
+var x: typeof a;
+import a2 = require('elidingImportNames_main1'); // alias not used in typeof
+var b2 = a2;
+
+
+// @Filename: elidingImportNames_main.ts
+export var main = 10;
+
+// @Filename: elidingImportNames_main1.ts
+export var main = 10;