[modules] When a tag type that was imported from a module is referenced via an

elaborated-type-specifier, create a declaration of it to track that the current
module makes it visible too.

llvm-svn: 256907

1 files changed, 22 insertions, 0 deletions

diff --git a/clang/test/Modules/tag-injection.cpp b/clang/test/Modules/tag-injection.cpp
new file mode 100644
index 00000000000..75c8b5fecdb
--- /dev/null
+++ b/clang/test/Modules/tag-injection.cpp
@@ -0,0 +1,22 @@
+// RUN: rm -rf %t
+// RUN: mkdir %t
+// RUN: touch %t/a.h
+// RUN: echo 'struct X {};' > %t/b.h
+// RUN: echo 'module X { module a { header "a.h" } module b { header "b.h" } }' > %t/x.modulemap
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -x c++ -fmodule-map-file=%t/x.modulemap %s -I%t -verify -fmodules-local-submodule-visibility -std=c++11
+
+#include "a.h"
+
+struct A {
+  // This use of 'struct X' makes the declaration (but not definition) of X visible.
+  virtual void f(struct X *p);
+};
+
+namespace N {
+  struct B : A {
+    void f(struct X *q) override;
+  };
+}
+
+X x; // expected-error {{definition of 'X' must be imported from module 'X.b' before it is required}}
+// expected-note@b.h:1 {{here}}