fix module record nonambiguous case, add test for it

src/compiler/checker.ts

@@ -1113,7 +1113,7 @@ namespace ts {
                         };
                     }
                 }
-                else if (lookupTable && exportNode && id !== "default" && hasProperty(target, id)) {
+                else if (lookupTable && exportNode && id !== "default" && hasProperty(target, id) && target[id] !== source[id]) {
                     lookupTable[id].exportsWithDuplicate.push(exportNode);
                 }
             }

tests/baselines/reference/moduleSameValueDuplicateExportedBindings.js

@@ -0,0 +1,28 @@
+//// [tests/cases/compiler/moduleSameValueDuplicateExportedBindings.ts] ////
+
+//// [a.ts]
+export * from "./b";
+export * from "./c";
+
+//// [b.ts]
+export * from "./c";
+
+//// [c.ts]
+export var foo = 42;
+
+//// [c.js]
+"use strict";
+exports.foo = 42;
+//// [b.js]
+"use strict";
+function __export(m) {
+    for (var p in m) if (!exports.hasOwnProperty(p)) exports[p] = m[p];
+}
+__export(require("./c"));
+//// [a.js]
+"use strict";
+function __export(m) {
+    for (var p in m) if (!exports.hasOwnProperty(p)) exports[p] = m[p];
+}
+__export(require("./b"));
+__export(require("./c"));

tests/baselines/reference/moduleSameValueDuplicateExportedBindings.symbols

@@ -0,0 +1,11 @@
+=== tests/cases/compiler/a.ts ===
+export * from "./b";
+No type information for this code.export * from "./c";
+No type information for this code.
+No type information for this code.=== tests/cases/compiler/b.ts ===
+export * from "./c";
+No type information for this code.
+No type information for this code.=== tests/cases/compiler/c.ts ===
+export var foo = 42;
+>foo : Symbol(foo, Decl(c.ts, 0, 10))
+

tests/baselines/reference/moduleSameValueDuplicateExportedBindings.types

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/a.ts ===
+export * from "./b";
+No type information for this code.export * from "./c";
+No type information for this code.
+No type information for this code.=== tests/cases/compiler/b.ts ===
+export * from "./c";
+No type information for this code.
+No type information for this code.=== tests/cases/compiler/c.ts ===
+export var foo = 42;
+>foo : number
+>42 : number
+

tests/cases/compiler/moduleSameValueDuplicateExportedBindings.ts

@@ -0,0 +1,10 @@
+// @module: commonjs
+// @filename: a.ts
+export * from "./b";
+export * from "./c";
+
+// @filename: b.ts
+export * from "./c";
+
+// @filename: c.ts
+export var foo = 42;