Index: clang/include/clang/AST/DeclBase.h
===================================================================
--- clang/include/clang/AST/DeclBase.h
+++ clang/include/clang/AST/DeclBase.h
@@ -1142,6 +1142,11 @@
   /// that are missing from the lookup table.
   mutable bool HasLazyExternalLexicalLookups : 1;
 
+  /// \brief If \c true, lookups should only return identifier from
+  /// DeclContext scope (for example TranslationUnit). Used in
+  /// LookupQualifiedName()
+  mutable bool UseQualifiedLookup : 1;
+
   /// \brief Pointer to the data structure used to lookup declarations
   /// within this context (or a DependentStoredDeclsMap if this is a
   /// dependent context). We maintain the invariant that, if the map
@@ -1176,6 +1181,7 @@
         ExternalVisibleStorage(false),
         NeedToReconcileExternalVisibleStorage(false),
         HasLazyLocalLexicalLookups(false), HasLazyExternalLexicalLookups(false),
+        UseQualifiedLookup(false),
         LookupPtr(nullptr), FirstDecl(nullptr), LastDecl(nullptr) {}
 
 public:
@@ -1756,6 +1762,16 @@
                  D == LastDecl);
   }
 
+  bool setUseQualifiedLookup(bool use = true) {
+    bool old_value = UseQualifiedLookup;
+    UseQualifiedLookup = use;
+    return old_value;
+  }
+
+  bool shouldUseQualifiedLookup() const {
+    return UseQualifiedLookup;
+  }
+
   static bool classof(const Decl *D);
   static bool classof(const DeclContext *D) { return true; }
 
Index: clang/lib/Sema/SemaLookup.cpp
===================================================================
--- clang/lib/Sema/SemaLookup.cpp
+++ clang/lib/Sema/SemaLookup.cpp
@@ -204,6 +204,13 @@
                                                UnqualUsingEntry::Comparator()));
     }
   };
+
+  class Deinitializer {
+    std::function<void()> Deinit;
+  public:
+    Deinitializer(const std::function<void()>& d): Deinit(d) {}
+    ~Deinitializer() { Deinit(); }
+  };
 }
 
 // Retrieve the set of identifier namespaces that correspond to a
@@ -1852,6 +1859,9 @@
          "Declaration context must already be complete!");
 
   // Perform qualified name lookup into the LookupCtx.
+  bool oldval = LookupCtx->setUseQualifiedLookup();
+  Deinitializer deinit([&]() { LookupCtx->setUseQualifiedLookup(oldval); });
+
   if (LookupDirect(*this, R, LookupCtx)) {
     R.resolveKind();
     if (isa<CXXRecordDecl>(LookupCtx))