Sema: Properly support Microsoft-mode template arguments

Summary:
There were two things known to be wrong with our implementation of MSVC
mode template arguments:

- We didn't properly handle __uuidof/CXXUuidofExpr and skipped all type
  checking completely.
- We didn't allow for MSVC's extension of allowing certain constant
  "foldable" expressions from showing up in template arguments.
  They allow various casts dereference and address-of operations.
  We can make it more general as we find further peculiarities but this
  is the known extent.

Reviewers: rsmith, doug.gregor, rjmccall

Reviewed By: doug.gregor

CC: cfe-commits, rnk

Differential Revision: http://llvm-reviews.chandlerc.com/D1444

llvm-svn: 189087

1 files changed, 5 insertions, 2 deletions

diff --git a/clang/test/Parser/MicrosoftExtensions.cpp b/clang/test/Parser/MicrosoftExtensions.cpp
index 3df461053d4..1102fcbcec8 100644
--- a/clang/test/Parser/MicrosoftExtensions.cpp
+++ b/clang/test/Parser/MicrosoftExtensions.cpp
@@ -95,10 +95,10 @@ void template_uuid()
 }
 
 
-template <class T, const GUID* g = &__uuidof(T)>
+template <class T, const GUID* g = &__uuidof(T)> // expected-note {{template parameter is declared here}}
 class COM_CLASS_TEMPLATE  { };
 
-typedef COM_CLASS_TEMPLATE<struct_with_uuid, &__uuidof(struct_with_uuid)> COM_TYPE_1;
+typedef COM_CLASS_TEMPLATE<struct_with_uuid, &*&__uuidof(struct_with_uuid)> COM_TYPE_1; // expected-warning {{non-type template argument containing a dereference operation is a Microsoft extension}}
 typedef COM_CLASS_TEMPLATE<struct_with_uuid> COM_TYPE_2;
 
 template <class T, const GUID& g>
@@ -112,6 +112,9 @@ typedef COM_CLASS_TEMPLATE_REF<struct_with_uuid, __uuidof(struct_with_uuid)> COM
   }
   struct __declspec(uuid("000000A0-0000-0000-C000-000000000049")) late_defined_uuid;
 
+COM_CLASS_TEMPLATE_REF<int, __uuidof(struct_with_uuid)> good_template_arg;
+
+COM_CLASS_TEMPLATE<int, __uuidof(struct_with_uuid)> bad_template_arg; // expected-error {{non-type template argument of type 'const _GUID' is not a constant expression}}
 
 class CtorCall {
 public: