Permit redeclaration of tags introduced by using decls

This valid construct appears in MSVC headers where it's used to provide a
definition for the '::type_info' compiler builtin type.

llvm-svn: 199490

1 files changed, 3 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index e14fc53750c..62fedbf9691 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -10681,7 +10681,8 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
   }
 
   if (!Previous.empty()) {
-    NamedDecl *PrevDecl = (*Previous.begin())->getUnderlyingDecl();
+    NamedDecl *DirectPrevDecl = *Previous.begin();
+    NamedDecl *PrevDecl = DirectPrevDecl->getUnderlyingDecl();
 
     // It's okay to have a tag decl in the same scope as a typedef
     // which hides a tag decl in the same scope.  Finding this
@@ -10713,7 +10714,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
       // in the same scope (so that the definition/declaration completes or
       // rementions the tag), reuse the decl.
       if (TUK == TUK_Reference || TUK == TUK_Friend ||
-          isDeclInScope(PrevDecl, SearchDC, S,
+          isDeclInScope(DirectPrevDecl, SearchDC, S,
                         SS.isNotEmpty() || isExplicitSpecialization)) {
         // Make sure that this wasn't declared as an enum and now used as a
         // struct or something similar.