Introduce a new OpaquePtr<N> struct type, which is a simple POD wrapper for a
pointer.  Its purpose in life is to be a glorified void*, but which does not
implicitly convert to void* or other OpaquePtr's with a different UID.

Introduce Action::DeclPtrTy which is a typedef for OpaquePtr<0>.  Change the 
entire parser/sema interface to use DeclPtrTy instead of DeclTy*.  This
makes the C++ compiler enforce that these aren't convertible to other opaque
types.

We should also convert ExprTy, StmtTy, TypeTy, AttrTy, BaseTy, etc,
but I don't plan to do that in the short term.

The one outstanding known problem with this patch is that we lose the 
bitmangling optimization where ActionResult<DeclPtrTy> doesn't know how to
bitmangle the success bit into the low bit of DeclPtrTy.  I will rectify
this with a subsequent patch.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67952 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 025a245..ca6d7fe 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -4323,7 +4323,7 @@
                                  Method->getResultType().getNonReferenceType(),
                                  OpLoc);
   return ActOnMemberReferenceExpr(S, ExprArg(*this, Base), OpLoc, tok::arrow,
-                                  MemberLoc, Member).release();
+                                  MemberLoc, Member, DeclPtrTy()).release();
 }
 
 /// FixOverloadedFunctionReference - E is an expression that refers to