[modules] Fix bug where an anonymous namespace could cause the containing

namespace to not merge properly.

We have an invariant here: after a declaration reads its canonical declaration,
it can assume the canonical declaration is fully merged. This invariant can be
violated if deserializing some declaration triggers the deserialization of a
later declaration, because that later declaration can in turn deserialize a
redeclaration of that first declaration before it is fully merged.

The anonymous namespace for a namespace gets stored with the first declaration
of that namespace, which may be before its parent namespace, so defer loading
it until after we've finished merging the surrounding namespace.

llvm-svn: 232455

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/test/Modules/anon-namespace.cpp b/clang/test/Modules/anon-namespace.cpp
new file mode 100644
index 00000000000..6c085ebc885
--- /dev/null
+++ b/clang/test/Modules/anon-namespace.cpp
@@ -0,0 +1,6 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I%S/Inputs/anon-namespace -verify %s
+// expected-no-diagnostics
+#include "b1.h"
+#include "c.h"
+using namespace N;