Tests: Add a clang submodule test to extensions_transitive_objc.swift.

Author: tshortli

test/NameLookup/Inputs/Categories/Categories_D.h

@@ -0,0 +1 @@
+// Intentionally empty

test/NameLookup/Inputs/Categories/Categories_D.swift

@@ -0,0 +1,2 @@
+import Categories_C
+import Categories_D.Submodule

test/NameLookup/Inputs/Categories/Categories_E.swift

@@ -0,0 +1,5 @@
+@import Categories_A;
+
+@interface X (SubmoduleOfD)
+- (void)fromSubmoduleOfD;
+@end

test/NameLookup/Inputs/Categories/Submodule.h

@@ -12,3 +12,14 @@ module Categories_C {
   header "Categories_C.h"
   export *
 }
+
+module Categories_D {
+  header "Categories_D.h"
+  export *
+
+  explicit module Submodule {
+    header "Submodule.h"
+    export *
+  }
+}
+

test/NameLookup/Inputs/Categories/module.modulemap

@@ -2,21 +2,24 @@
 // RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/Categories -o %t %S/Inputs/Categories/Categories_A.swift
 // RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/Categories -o %t %S/Inputs/Categories/Categories_B.swift
 // RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/Categories -o %t %S/Inputs/Categories/Categories_C.swift
-// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/Categories -o %t %S/Inputs/Categories/Categories_D.swift
+// RUN: %target-swift-frontend -emit-module -I %t -I %S/Inputs/Categories -o %t %S/Inputs/Categories/Categories_E.swift
 // RUN: %target-swift-frontend -typecheck %s -I %t -I %S/Inputs/Categories -verify -enable-experimental-feature ExtensionImportVisibility
 
 // REQUIRES: objc_interop
 
 import Categories_B
-import Categories_D
-// expected-note 2 {{add import of module 'Categories_C'}}{{1-1=import Categories_C\n}}
+import Categories_E
+
+// expected-note@-1 2 {{add import of module 'Categories_C'}}{{1-1=import Categories_C\n}}
+// expected-note@-2 {{add import of module 'Categories_D'}}{{1-1=import Categories_D\n}}
 func test(x: X) {
   x.fromA()
   x.fromOverlayForA()
   x.fromB()
   x.fromOverlayForB()
   x.fromC() // expected-error {{class method 'fromC()' is not available due to missing import of defining module 'Categories_C'}}
   x.fromOverlayForC() // expected-error {{instance method 'fromOverlayForC()' is not available due to missing import of defining module 'Categories_C'}}
+  x.fromSubmoduleOfD() // expected-error {{class method 'fromSubmoduleOfD()' is not available due to missing import of defining module 'Categories_D'}}
 }
 
 func testAnyObject(a: AnyObject) {