Merge pull request #24212 from Microsoft/Fix24199

Add undefined guard

Author: mhegazy

src/compiler/transformers/declarations.ts

@@ -217,16 +217,18 @@ namespace ts {
 
             function getFileReferenceForTypeName(typeName: string): FileReference | undefined {
                 // Elide type references for which we have imports
-                for (const importStatement of emittedImports) {
-                    if (isImportEqualsDeclaration(importStatement) && isExternalModuleReference(importStatement.moduleReference)) {
-                        const expr = importStatement.moduleReference.expression;
-                        if (isStringLiteralLike(expr) && expr.text === typeName) {
+                if (emittedImports) {
+                    for (const importStatement of emittedImports) {
+                        if (isImportEqualsDeclaration(importStatement) && isExternalModuleReference(importStatement.moduleReference)) {
+                            const expr = importStatement.moduleReference.expression;
+                            if (isStringLiteralLike(expr) && expr.text === typeName) {
+                                return undefined;
+                            }
+                        }
+                        else if (isImportDeclaration(importStatement) && isStringLiteral(importStatement.moduleSpecifier) && importStatement.moduleSpecifier.text === typeName) {
                             return undefined;
                         }
                     }
-                    else if (isImportDeclaration(importStatement) && isStringLiteral(importStatement.moduleSpecifier) && importStatement.moduleSpecifier.text === typeName) {
-                        return undefined;
-                    }
                 }
                 return { fileName: typeName, pos: -1, end: -1 };
             }
@@ -1325,4 +1327,4 @@ namespace ts {
         }
         return false;
     }
-}
+}

tests/baselines/reference/declarationFilesGeneratingTypeReferences.js

@@ -0,0 +1,46 @@
+//// [tests/cases/compiler/declarationFilesGeneratingTypeReferences.ts] ////
+
+//// [index.d.ts]
+interface JQuery {
+
+}
+
+//// [app.ts]
+/// <reference types="jquery"/>
+namespace Test {
+    export var x: JQuery;
+}
+
+//// [out.js]
+/// <reference types="jquery"/>
+var Test;
+(function (Test) {
+})(Test || (Test = {}));
+
+
+//// [out.d.ts]
+/// <reference types="jquery" />
+declare namespace Test {
+    var x: JQuery;
+}
+
+
+//// [DtsFileErrors]
+
+
+out.d.ts(1,23): error TS2688: Cannot find type definition file for 'jquery'.
+
+
+==== /a/node_modules/@types/jquery/index.d.ts (0 errors) ====
+    interface JQuery {
+    
+    }
+    
+==== out.d.ts (1 errors) ====
+    /// <reference types="jquery" />
+                          ~~~~~~
+!!! error TS2688: Cannot find type definition file for 'jquery'.
+    declare namespace Test {
+        var x: JQuery;
+    }
+    

tests/baselines/reference/declarationFilesGeneratingTypeReferences.symbols

@@ -0,0 +1,15 @@
+=== /a/node_modules/@types/jquery/index.d.ts ===
+interface JQuery {
+>JQuery : Symbol(JQuery, Decl(index.d.ts, 0, 0))
+
+}
+
+=== /a/app.ts ===
+/// <reference types="jquery"/>
+namespace Test {
+>Test : Symbol(Test, Decl(app.ts, 0, 0))
+
+    export var x: JQuery;
+>x : Symbol(x, Decl(app.ts, 2, 14))
+>JQuery : Symbol(JQuery, Decl(index.d.ts, 0, 0))
+}

tests/baselines/reference/declarationFilesGeneratingTypeReferences.types

@@ -0,0 +1,15 @@
+=== /a/node_modules/@types/jquery/index.d.ts ===
+interface JQuery {
+>JQuery : JQuery
+
+}
+
+=== /a/app.ts ===
+/// <reference types="jquery"/>
+namespace Test {
+>Test : typeof Test
+
+    export var x: JQuery;
+>x : JQuery
+>JQuery : JQuery
+}

tests/cases/compiler/declarationFilesGeneratingTypeReferences.ts

@@ -0,0 +1,13 @@
+// @declaration: true
+// @outFile: out.js
+
+// @filename: /a/node_modules/@types/jquery/index.d.ts
+interface JQuery {
+
+}
+
+// @filename: /a/app.ts
+/// <reference types="jquery"/>
+namespace Test {
+    export var x: JQuery;
+}