fix(36936): fix crash caused by resolving non existent export (microsoft#37077)

a-tarasyuk · web-flow · commit a510cad873db · 2020-03-17T13:21:20.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -3095,8 +3095,8 @@ namespace ts {
         function resolveExternalModuleSymbol(moduleSymbol: Symbol, dontResolveAlias?: boolean): Symbol;
         function resolveExternalModuleSymbol(moduleSymbol: Symbol | undefined, dontResolveAlias?: boolean): Symbol | undefined;
         function resolveExternalModuleSymbol(moduleSymbol: Symbol, dontResolveAlias?: boolean): Symbol {
-            if (moduleSymbol) {
-                const exportEquals = resolveSymbol(moduleSymbol.exports!.get(InternalSymbolName.ExportEquals), dontResolveAlias);
+            if (moduleSymbol?.exports) {
+                const exportEquals = resolveSymbol(moduleSymbol.exports.get(InternalSymbolName.ExportEquals), dontResolveAlias);
                 const exported = getCommonJsExportEquals(getMergedSymbol(exportEquals), getMergedSymbol(moduleSymbol));
                 return getMergedSymbol(exported) || moduleSymbol;
             }
diff --git a/tests/baselines/reference/tsxResolveExternalModuleExportsTypes.js b/tests/baselines/reference/tsxResolveExternalModuleExportsTypes.js
@@ -0,0 +1,26 @@
+//// [tests/cases/compiler/tsxResolveExternalModuleExportsTypes.ts] ////
+
+//// [index.d.ts]
+declare var a: a.Foo;
+declare namespace a {
+    interface Foo {}
+}
+export = a;
+
+//// [index.d.ts]
+import * as a from 'a';
+declare module 'a' {
+    namespace Test {}
+
+    interface Foo {
+        Test: null;
+    }
+}
+
+//// [foo.tsx]
+import { Test } from 'a';
+const Foo = (<h1></h1>);
+
+
+//// [foo.jsx]
+var Foo = (<h1></h1>);
diff --git a/tests/baselines/reference/tsxResolveExternalModuleExportsTypes.symbols b/tests/baselines/reference/tsxResolveExternalModuleExportsTypes.symbols
@@ -0,0 +1,42 @@
+=== /node_modules/@types/a/index.d.ts ===
+declare var a: a.Foo;
+>a : Symbol(a, Decl(index.d.ts, 0, 11), Decl(index.d.ts, 0, 21), Decl(index.d.ts, 0, 23))
+>a : Symbol(a, Decl(index.d.ts, 0, 11), Decl(index.d.ts, 0, 21))
+>Foo : Symbol(a.Foo, Decl(index.d.ts, 1, 21))
+
+declare namespace a {
+>a : Symbol(a, Decl(index.d.ts, 0, 11), Decl(index.d.ts, 0, 21), Decl(index.d.ts, 0, 23))
+
+    interface Foo {}
+>Foo : Symbol(Foo, Decl(index.d.ts, 1, 21), Decl(index.d.ts, 2, 21))
+}
+export = a;
+>a : Symbol(a, Decl(index.d.ts, 0, 11), Decl(index.d.ts, 0, 21))
+
+=== /node_modules/@types/b/index.d.ts ===
+import * as a from 'a';
+>a : Symbol(a, Decl(index.d.ts, 0, 6))
+
+declare module 'a' {
+>'a' : Symbol(a, Decl(index.d.ts, 0, 11), Decl(index.d.ts, 0, 21), Decl(index.d.ts, 0, 23))
+
+    namespace Test {}
+>Test : Symbol(Test, Decl(index.d.ts, 1, 20))
+
+    interface Foo {
+>Foo : Symbol(Foo, Decl(index.d.ts, 1, 21), Decl(index.d.ts, 2, 21))
+
+        Test: null;
+>Test : Symbol(Foo.Test, Decl(index.d.ts, 4, 19))
+    }
+}
+
+=== tests/cases/compiler/foo.tsx ===
+import { Test } from 'a';
+>Test : Symbol(Test, Decl(foo.tsx, 0, 8))
+
+const Foo = (<h1></h1>);
+>Foo : Symbol(Foo, Decl(foo.tsx, 1, 5))
+>h1 : Symbol(JSX.IntrinsicElements.h1, Decl(react.d.ts, 2410, 47))
+>h1 : Symbol(JSX.IntrinsicElements.h1, Decl(react.d.ts, 2410, 47))
+
diff --git a/tests/baselines/reference/tsxResolveExternalModuleExportsTypes.types b/tests/baselines/reference/tsxResolveExternalModuleExportsTypes.types
@@ -0,0 +1,38 @@
+=== /node_modules/@types/a/index.d.ts ===
+declare var a: a.Foo;
+>a : import("/node_modules/@types/a/index.d.ts").Foo
+>a : any
+
+declare namespace a {
+    interface Foo {}
+}
+export = a;
+>a : import("/node_modules/@types/a/index.d.ts").Foo
+
+=== /node_modules/@types/b/index.d.ts ===
+import * as a from 'a';
+>a : a.Foo
+
+declare module 'a' {
+>'a' : Foo
+
+    namespace Test {}
+
+    interface Foo {
+        Test: null;
+>Test : null
+>null : null
+    }
+}
+
+=== tests/cases/compiler/foo.tsx ===
+import { Test } from 'a';
+>Test : null
+
+const Foo = (<h1></h1>);
+>Foo : JSX.Element
+>(<h1></h1>) : JSX.Element
+><h1></h1> : JSX.Element
+>h1 : any
+>h1 : any
+
diff --git a/tests/cases/compiler/tsxResolveExternalModuleExportsTypes.ts b/tests/cases/compiler/tsxResolveExternalModuleExportsTypes.ts
@@ -0,0 +1,24 @@
+// @module: ES2015
+// @jsx: preserve
+// @libFiles: react.d.ts,lib.d.ts
+
+// @Filename: /node_modules/@types/a/index.d.ts
+declare var a: a.Foo;
+declare namespace a {
+    interface Foo {}
+}
+export = a;
+
+// @Filename: /node_modules/@types/b/index.d.ts
+import * as a from 'a';
+declare module 'a' {
+    namespace Test {}
+
+    interface Foo {
+        Test: null;
+    }
+}
+
+// @Filename: foo.tsx
+import { Test } from 'a';
+const Foo = (<h1></h1>);
