Support decltype in nested-name-specifiers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@145785 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index d9983d4..79d2ec2 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -168,6 +168,22 @@
     *MayBePseudoDestructor = false;
   }
 
+  if (Tok.is(tok::kw_decltype) || Tok.is(tok::annot_decltype)) {
+    DeclSpec DS(AttrFactory);
+    SourceLocation DeclLoc = Tok.getLocation();
+    SourceLocation EndLoc  = ParseDecltypeSpecifier(DS);
+    if (Tok.isNot(tok::coloncolon)) {
+      AnnotateExistingDecltypeSpecifier(DS, DeclLoc, EndLoc);
+      return false;
+    }
+    
+    SourceLocation CCLoc = ConsumeToken();
+    if (Actions.ActOnCXXNestedNameSpecifierDecltype(SS, DS, CCLoc))
+      SS.SetInvalid(SourceRange(DeclLoc, CCLoc));
+
+    HasScopeSpecifier = true;
+  }
+
   while (true) {
     if (HasScopeSpecifier) {
       // C++ [basic.lookup.classref]p5: