1 files changed, 6 insertions, 16 deletions
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 74bffb2a044..910ebcf05dd 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -7206,23 +7206,13 @@ Decl *Sema::ActOnStartNamespaceDef(Scope *NamespcScope,
     //   treated as an original-namespace-name.
     //
     // Since namespace names are unique in their scope, and we don't
-    // look through using directives, just look for any ordinary names.
-    
-    const unsigned IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Member | 
-    Decl::IDNS_Type | Decl::IDNS_Using | Decl::IDNS_Tag | 
-    Decl::IDNS_Namespace;
-    NamedDecl *PrevDecl = nullptr;
-    DeclContext::lookup_result R = CurContext->getRedeclContext()->lookup(II);
-    for (DeclContext::lookup_iterator I = R.begin(), E = R.end(); I != E;
-         ++I) {
-      if ((*I)->getIdentifierNamespace() & IDNS) {
-        PrevDecl = *I;
-        break;
-      }
-    }
-    
+    // look through using directives, just look for any ordinary names
+    // as if by qualified name lookup.
+    LookupResult R(*this, II, IdentLoc, LookupOrdinaryName, ForRedeclaration);
+    LookupQualifiedName(R, CurContext->getRedeclContext());
+    NamedDecl *PrevDecl = R.getAsSingle<NamedDecl>();
     PrevNS = dyn_cast_or_null<NamespaceDecl>(PrevDecl);
-    
+
     if (PrevNS) {
       // This is an extended namespace definition.
       if (IsInline != PrevNS->isInline())