Implement explicit instantiations of member classes of class templates, e.g.,

  template<typename T>
  struct X {
    struct Inner;
  };

  template struct X<int>::Inner;

This change is larger than it looks because it also fixes some
a problem with nested-name-specifiers and tags. We weren't requiring
the DeclContext associated with the scope specifier of a tag to be
complete. Therefore, when looking for something like "struct
X<int>::Inner", we weren't instantiating X<int>. 

This, naturally, uncovered a problem with member pointers, where we
were requiring the left-hand side of a member pointer access
expression (e.g., x->*) to be a complete type. However, this is wrong:
the semantics of this expression does not require a complete type (EDG
agrees).

Stuart vouched for me. Blame him.

llvm-svn: 71756

1 files changed, 1 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 5f2b705498e..57aae296319 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -994,10 +994,7 @@ QualType Sema::CheckPointerToMemberOperands(
     Diag(Loc, diag::err_bad_memptr_rhs)
       << OpSpelling << RType << rex->getSourceRange();
     return QualType();
-  } else if (RequireCompleteType(Loc, QualType(MemPtr->getClass(), 0),
-                                 diag::err_memptr_rhs_incomplete,
-                                 rex->getSourceRange()))
-    return QualType();
+  } 
 
   QualType Class(MemPtr->getClass(), 0);