Index: include/clang/Sema/CodeCompleteConsumer.h
===================================================================
--- include/clang/Sema/CodeCompleteConsumer.h
+++ include/clang/Sema/CodeCompleteConsumer.h
@@ -272,11 +272,15 @@
     CCC_Type,
 
     /// Code completion occurred where a new name is expected.
-    CCC_Name,
+    CCC_NewName,
 
-    /// Code completion occurred where a new name is expected and a
-    /// qualified name is permissible.
-    CCC_PotentiallyQualifiedName,
+    /// Code completion occurred where both a new name and an existing symbol is
+    /// permissible.
+    CCC_SymbolOrNewName,
+
+    /// Code completion occurred where an existing name(such as type, function
+    /// or variable) is expected.
+    CCC_Symbol,
 
     /// Code completion occurred where an macro is being defined.
     CCC_MacroName,
Index: lib/Frontend/ASTUnit.cpp
===================================================================
--- lib/Frontend/ASTUnit.cpp
+++ lib/Frontend/ASTUnit.cpp
@@ -282,7 +282,7 @@
 
 /// Determine the set of code-completion contexts in which this
 /// declaration should be shown.
-static unsigned getDeclShowContexts(const NamedDecl *ND,
+static uint64_t getDeclShowContexts(const NamedDecl *ND,
                                     const LangOptions &LangOpts,
                                     bool &IsNestedNameSpecifier) {
   IsNestedNameSpecifier = false;
@@ -436,14 +436,15 @@
           | (1LL << CodeCompletionContext::CCC_UnionTag)
           | (1LL << CodeCompletionContext::CCC_ClassOrStructTag)
           | (1LL << CodeCompletionContext::CCC_Type)
-          | (1LL << CodeCompletionContext::CCC_PotentiallyQualifiedName)
+          | (1LL << CodeCompletionContext::CCC_Symbol)
+          | (1LL << CodeCompletionContext::CCC_SymbolOrNewName)
           | (1LL << CodeCompletionContext::CCC_ParenthesizedExpression);
 
         if (isa<NamespaceDecl>(R.Declaration) ||
             isa<NamespaceAliasDecl>(R.Declaration))
           NNSContexts |= (1LL << CodeCompletionContext::CCC_Namespace);
 
-        if (unsigned RemainingContexts
+        if (uint64_t RemainingContexts
                                 = NNSContexts & ~CachedResult.ShowInContexts) {
           // If there any contexts where this completion can be a
           // nested-name-specifier but isn't already an option, create a
@@ -1951,8 +1952,8 @@
   case CodeCompletionContext::CCC_ObjCPropertyAccess:
   case CodeCompletionContext::CCC_Namespace:
   case CodeCompletionContext::CCC_Type:
-  case CodeCompletionContext::CCC_Name:
-  case CodeCompletionContext::CCC_PotentiallyQualifiedName:
+  case CodeCompletionContext::CCC_Symbol:
+  case CodeCompletionContext::CCC_SymbolOrNewName:
   case CodeCompletionContext::CCC_ParenthesizedExpression:
   case CodeCompletionContext::CCC_ObjCInterfaceName:
     break;
@@ -1977,6 +1978,7 @@
   case CodeCompletionContext::CCC_ObjCClassMessage:
   case CodeCompletionContext::CCC_ObjCCategoryName:
   case CodeCompletionContext::CCC_IncludedFile:
+  case CodeCompletionContext::CCC_NewName:
     // We're looking for nothing, or we're looking for names that cannot
     // be hidden.
     return;
Index: lib/Sema/CodeCompleteConsumer.cpp
===================================================================
--- lib/Sema/CodeCompleteConsumer.cpp
+++ lib/Sema/CodeCompleteConsumer.cpp
@@ -49,6 +49,8 @@
   case CCC_Expression:
   case CCC_ObjCMessageReceiver:
   case CCC_ParenthesizedExpression:
+  case CCC_Symbol:
+  case CCC_SymbolOrNewName:
     return true;
 
   case CCC_TopLevel:
@@ -65,8 +67,7 @@
   case CCC_ObjCProtocolName:
   case CCC_Namespace:
   case CCC_Type:
-  case CCC_Name:
-  case CCC_PotentiallyQualifiedName:
+  case CCC_NewName:
   case CCC_MacroName:
   case CCC_MacroNameUse:
   case CCC_PreprocessorExpression:
@@ -128,10 +129,12 @@
     return "Namespace";
   case CCKind::CCC_Type:
     return "Type";
-  case CCKind::CCC_Name:
-    return "Name";
-  case CCKind::CCC_PotentiallyQualifiedName:
-    return "PotentiallyQualifiedName";
+  case CCKind::CCC_NewName:
+    return "NewName";
+  case CCKind::CCC_Symbol:
+    return "Symbol";
+  case CCKind::CCC_SymbolOrNewName:
+    return "SymbolOrNewName";
   case CCKind::CCC_MacroName:
     return "MacroName";
   case CCKind::CCC_MacroNameUse:
Index: lib/Sema/SemaCodeComplete.cpp
===================================================================
--- lib/Sema/SemaCodeComplete.cpp
+++ lib/Sema/SemaCodeComplete.cpp
@@ -3753,11 +3753,14 @@
                                 bool AllowNonIdentifiers,
                                 bool AllowNestedNameSpecifiers) {
   typedef CodeCompletionResult Result;
-  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
-                        CodeCompleter->getCodeCompletionTUInfo(),
-                        AllowNestedNameSpecifiers
-                          ? CodeCompletionContext::CCC_PotentiallyQualifiedName
-                          : CodeCompletionContext::CCC_Name);
+  ResultBuilder Results(
+      *this, CodeCompleter->getAllocator(),
+      CodeCompleter->getCodeCompletionTUInfo(),
+      AllowNestedNameSpecifiers
+          // FIXME: Try to separate codepath leading here to deduce whether we
+          // need an existing symbol or a new one.
+          ? CodeCompletionContext::CCC_SymbolOrNewName
+          : CodeCompletionContext::CCC_NewName);
   Results.EnterNewScope();
 
   // Type qualifiers can come after names.
@@ -4841,7 +4844,7 @@
   // it can be useful for global code completion which have information about
   // contexts/symbols that are not in the AST.
   if (SS.isInvalid()) {
-    CodeCompletionContext CC(CodeCompletionContext::CCC_Name);
+    CodeCompletionContext CC(CodeCompletionContext::CCC_Symbol);
     CC.setCXXScopeSpecifier(SS);
     HandleCodeCompleteResults(this, CodeCompleter, CC, nullptr, 0);
     return;
@@ -4859,7 +4862,7 @@
 
   ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                         CodeCompleter->getCodeCompletionTUInfo(),
-                        CodeCompletionContext::CCC_Name);
+                        CodeCompletionContext::CCC_Symbol);
   Results.EnterNewScope();
 
   // The "template" keyword can follow "::" in the grammar, but only
@@ -4899,7 +4902,10 @@
 
   ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                         CodeCompleter->getCodeCompletionTUInfo(),
-                        CodeCompletionContext::CCC_PotentiallyQualifiedName,
+                        // This can be both a using alias or using
+                        // declaration, in the former we expect a new name and a
+                        // symbol in the latter case.
+                        CodeCompletionContext::CCC_SymbolOrNewName,
                         &ResultBuilder::IsNestedNameSpecifier);
   Results.EnterNewScope();
 
@@ -5051,7 +5057,7 @@
 
   ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                         CodeCompleter->getCodeCompletionTUInfo(),
-                        CodeCompletionContext::CCC_PotentiallyQualifiedName);
+                        CodeCompletionContext::CCC_Symbol);
   Results.EnterNewScope();
 
   // Fill in any already-initialized fields or base classes.
Index: tools/libclang/CIndexCodeCompletion.cpp
===================================================================
--- tools/libclang/CIndexCodeCompletion.cpp
+++ tools/libclang/CIndexCodeCompletion.cpp
@@ -487,7 +487,8 @@
       contexts = CXCompletionContext_Namespace;
       break;
     }
-    case CodeCompletionContext::CCC_PotentiallyQualifiedName: {
+    case CodeCompletionContext::CCC_SymbolOrNewName:
+    case CodeCompletionContext::CCC_Symbol: {
       contexts = CXCompletionContext_NestedNameSpecifier;
       break;
     }
@@ -539,7 +540,7 @@
     case CodeCompletionContext::CCC_Other:
     case CodeCompletionContext::CCC_ObjCInterface:
     case CodeCompletionContext::CCC_ObjCImplementation:
-    case CodeCompletionContext::CCC_Name:
+    case CodeCompletionContext::CCC_NewName:
     case CodeCompletionContext::CCC_MacroName:
     case CodeCompletionContext::CCC_PreprocessorExpression:
     case CodeCompletionContext::CCC_PreprocessorDirective: