Tests: Verify MemberImportVisibility honors -public-module-name.

Author: tshortli

test/NameLookup/members_transitive_public_module_name.swift

@@ -0,0 +1,32 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %target-swift-frontend -emit-module -o %t %t/LibCore.swift -public-module-name Lib
+// RUN: %target-swift-frontend -emit-module -I %t -o %t %t/Lib.swift
+// RUN: %target-swift-frontend -typecheck -primary-file %t/main.swift %t/other.swift -I %t -verify -swift-version 5 -enable-upcoming-feature MemberImportVisibility
+
+// REQUIRES: swift_feature_MemberImportVisibility
+
+//--- main.swift
+
+import Swift
+// expected-note {{add import of module 'Lib'}}
+
+func foo(_ x: Int) -> Int {
+  x.bar // expected-error {{property 'bar' is not available due to missing import of defining module 'Lib'}}
+}
+
+//--- other.swift
+
+import Lib
+
+//--- Lib.swift
+
+@_exported import LibCore
+
+//--- LibCore.swift
+
+extension Int {
+  public var bar: Int {
+    return self < 0 ? -self : self
+  }
+}