Export declarations exporting aliases make the namespace instantiated (microsoft#54816)

Author: andrewbranch

src/compiler/binder.ts

@@ -313,7 +313,7 @@ import {
     unusedLabelIsError,
     VariableDeclaration,
     WhileStatement,
-    WithStatement,
+    WithStatement
 } from "./_namespaces/ts";
 import * as performance from "./_namespaces/ts.performance";
 
@@ -445,6 +445,14 @@ function getModuleInstanceStateForAliasTarget(specifier: ExportSpecifier, visite
                     if (found === ModuleInstanceState.Instantiated) {
                         return found;
                     }
+                    if (statement.kind === SyntaxKind.ImportEqualsDeclaration) {
+                        // Treat re-exports of import aliases as instantiated,
+                        // since they're ambiguous. This is consistent with
+                        // `export import x = mod.x` being treated as instantiated:
+                        //   import x = mod.x;
+                        //   export { x };
+                        found = ModuleInstanceState.Instantiated;
+                    }
                 }
             }
             if (found !== undefined) {

tests/baselines/reference/reExportAliasMakesInstantiated.js

@@ -0,0 +1,30 @@
+//// [tests/cases/conformance/internalModules/moduleDeclarations/reExportAliasMakesInstantiated.ts] ////
+
+//// [reExportAliasMakesInstantiated.ts]
+declare module pack1 {
+  const test1: string;
+  export { test1 };
+}
+declare module pack2 {
+  import test1 = pack1.test1;
+  export { test1 };
+}
+export import test1 = pack2.test1;
+
+declare module mod1 {
+  type test1 = string;
+  export { test1 };
+}
+declare module mod2 {
+  import test1 = mod1.test1;
+  export { test1 };
+}
+const test2 = mod2; // Possible false positive instantiation, but ok
+
+
+//// [reExportAliasMakesInstantiated.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.test1 = void 0;
+exports.test1 = pack2.test1;
+var test2 = mod2; // Possible false positive instantiation, but ok

tests/baselines/reference/reExportAliasMakesInstantiated.symbols

@@ -0,0 +1,52 @@
+//// [tests/cases/conformance/internalModules/moduleDeclarations/reExportAliasMakesInstantiated.ts] ////
+
+=== reExportAliasMakesInstantiated.ts ===
+declare module pack1 {
+>pack1 : Symbol(pack1, Decl(reExportAliasMakesInstantiated.ts, 0, 0))
+
+  const test1: string;
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 1, 7))
+
+  export { test1 };
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 2, 10))
+}
+declare module pack2 {
+>pack2 : Symbol(pack2, Decl(reExportAliasMakesInstantiated.ts, 3, 1))
+
+  import test1 = pack1.test1;
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 4, 22))
+>pack1 : Symbol(pack1, Decl(reExportAliasMakesInstantiated.ts, 0, 0))
+>test1 : Symbol(pack1.test1, Decl(reExportAliasMakesInstantiated.ts, 2, 10))
+
+  export { test1 };
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 6, 10))
+}
+export import test1 = pack2.test1;
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 7, 1))
+>pack2 : Symbol(pack2, Decl(reExportAliasMakesInstantiated.ts, 3, 1))
+>test1 : Symbol(pack2.test1, Decl(reExportAliasMakesInstantiated.ts, 6, 10))
+
+declare module mod1 {
+>mod1 : Symbol(mod1, Decl(reExportAliasMakesInstantiated.ts, 8, 34))
+
+  type test1 = string;
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 10, 21))
+
+  export { test1 };
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 12, 10))
+}
+declare module mod2 {
+>mod2 : Symbol(mod2, Decl(reExportAliasMakesInstantiated.ts, 13, 1))
+
+  import test1 = mod1.test1;
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 14, 21))
+>mod1 : Symbol(mod1, Decl(reExportAliasMakesInstantiated.ts, 8, 34))
+>test1 : Symbol(mod1.test1, Decl(reExportAliasMakesInstantiated.ts, 12, 10))
+
+  export { test1 };
+>test1 : Symbol(test1, Decl(reExportAliasMakesInstantiated.ts, 16, 10))
+}
+const test2 = mod2; // Possible false positive instantiation, but ok
+>test2 : Symbol(test2, Decl(reExportAliasMakesInstantiated.ts, 18, 5))
+>mod2 : Symbol(mod2, Decl(reExportAliasMakesInstantiated.ts, 13, 1))
+

tests/baselines/reference/reExportAliasMakesInstantiated.types

@@ -0,0 +1,50 @@
+//// [tests/cases/conformance/internalModules/moduleDeclarations/reExportAliasMakesInstantiated.ts] ////
+
+=== reExportAliasMakesInstantiated.ts ===
+declare module pack1 {
+>pack1 : typeof pack1
+
+  const test1: string;
+>test1 : string
+
+  export { test1 };
+>test1 : string
+}
+declare module pack2 {
+>pack2 : typeof pack2
+
+  import test1 = pack1.test1;
+>test1 : string
+>pack1 : typeof pack1
+>test1 : string
+
+  export { test1 };
+>test1 : string
+}
+export import test1 = pack2.test1;
+>test1 : string
+>pack2 : typeof pack2
+>test1 : string
+
+declare module mod1 {
+  type test1 = string;
+>test1 : string
+
+  export { test1 };
+>test1 : any
+}
+declare module mod2 {
+>mod2 : typeof mod2
+
+  import test1 = mod1.test1;
+>test1 : any
+>mod1 : any
+>test1 : string
+
+  export { test1 };
+>test1 : any
+}
+const test2 = mod2; // Possible false positive instantiation, but ok
+>test2 : typeof mod2
+>mod2 : typeof mod2
+

tests/cases/conformance/internalModules/moduleDeclarations/reExportAliasMakesInstantiated.ts

@@ -0,0 +1,19 @@
+declare module pack1 {
+  const test1: string;
+  export { test1 };
+}
+declare module pack2 {
+  import test1 = pack1.test1;
+  export { test1 };
+}
+export import test1 = pack2.test1;
+
+declare module mod1 {
+  type test1 = string;
+  export { test1 };
+}
+declare module mod2 {
+  import test1 = mod1.test1;
+  export { test1 };
+}
+const test2 = mod2; // Possible false positive instantiation, but ok