[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, 2 insertions, 0 deletions

diff --git a/clang/test/Modules/Inputs/anon-namespace/b2.h b/clang/test/Modules/Inputs/anon-namespace/b2.h
new file mode 100644
index 00000000000..8e7535f3626
--- /dev/null
+++ b/clang/test/Modules/Inputs/anon-namespace/b2.h
@@ -0,0 +1,2 @@
+#include "a.h"
+namespace N {}