Revert "[Modules] Fix regression when an elaborated-type-specifier mentions a hidden tag"

This is causing assertion failures; reverting until I can fix.

This reverts commit r255267

llvm-svn: 255324

1 files changed, 4 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 1d8f9b7d203..af5fdc95c90 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12121,12 +12121,10 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
 
     // In C++, we need to do a redeclaration lookup to properly
     // diagnose some problems.
-    // FIXME: this lookup is also used (with and without C++) to find a hidden
-    // declaration so that we don't get ambiguity errors when using a type
-    // declared by an elaborated-type-specifier.  In C that is not correct and
-    // we should instead merge compatible types found by lookup.
-    Previous.setRedeclarationKind(ForRedeclaration);
-    LookupQualifiedName(Previous, SearchDC);
+    if (getLangOpts().CPlusPlus) {
+      Previous.setRedeclarationKind(ForRedeclaration);
+      LookupQualifiedName(Previous, SearchDC);
+    }
   }
 
   // If we have a known previous declaration to use, then use it.