diff --git a/tests/cases/conformance/es6/modules/defaultExportsCannotMerge01.ts b/tests/cases/conformance/es6/modules/defaultExportsCannotMerge01.ts
new file mode 100644
index 00000000000..7caa9caf574
--- /dev/null
+++ b/tests/cases/conformance/es6/modules/defaultExportsCannotMerge01.ts
@@ -0,0 +1,31 @@
+// @module: commonjs
+// @target: ES5
+
+// @filename: m1.ts
+export default function Decl() {
+    return 0;
+}
+
+export interface Decl {
+    p1: number;
+    p2: number;
+}
+
+export namespace Decl {
+    export var x = 10;
+    export var y = 20;
+
+    interface I {
+    }
+}
+
+// @filename: m2.ts
+import Entity from "m1"
+
+Entity();
+
+var x: Entity;
+var y: Entity.I;
+
+Entity.x;
+Entity.y;
\ No newline at end of file
diff --git a/tests/cases/conformance/es6/modules/defaultExportsCannotMerge02.ts b/tests/cases/conformance/es6/modules/defaultExportsCannotMerge02.ts
new file mode 100644
index 00000000000..84172248e93
--- /dev/null
+++ b/tests/cases/conformance/es6/modules/defaultExportsCannotMerge02.ts
@@ -0,0 +1,19 @@
+// @module: commonjs
+// @target: ES5
+
+// @filename: m1.ts
+export default class foo {
+
+}
+
+export default function bar() {
+
+}
+
+var x = 10;
+export default x;
+
+// @filename: m2.ts
+import Entity from "m1"
+
+Entity();
\ No newline at end of file
diff --git a/tests/cases/conformance/es6/modules/defaultExportsCannotMerge03.ts b/tests/cases/conformance/es6/modules/defaultExportsCannotMerge03.ts
new file mode 100644
index 00000000000..1e9c8dabc13
--- /dev/null
+++ b/tests/cases/conformance/es6/modules/defaultExportsCannotMerge03.ts
@@ -0,0 +1,16 @@
+// @module: commonjs
+// @target: ES5
+
+// @filename: m1.ts
+export default function foo() {
+
+}
+
+export default function bar() {
+
+}
+
+// @filename: m2.ts
+import Entity from "m1"
+
+Entity();
\ No newline at end of file