Fix our semantic analysis of

  unqualified-id '('

in C++. The unqualified-id might not refer to any declaration in our
current scope, but declarations by that name might be found via
argument-dependent lookup. We now do so properly.

As part of this change, CXXDependentNameExpr, which was previously
designed to express the unqualified-id in the above constructor within
templates, has become UnresolvedFunctionNameExpr, which does
effectively the same thing but will work for both templates and
non-templates.

Additionally, we cope with all unqualified-ids, since ADL also applies
in cases like

  operator+(x, y)




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63733 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index e9dbc84..2a7c9a8 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -35,7 +35,7 @@
   DeclarationName ConvName 
     = Context.DeclarationNames.getCXXConversionFunctionName(ConvTypeCanon);
   return ActOnDeclarationNameExpr(S, OperatorLoc, ConvName, HasTrailingLParen,
-                                  &SS, /*ForceRes*/false, isAddressOfOperand);
+                                  &SS, isAddressOfOperand);
 }
 
 /// ActOnCXXOperatorFunctionIdExpr - Parse a C++ overloaded operator
@@ -51,7 +51,7 @@
                                      bool isAddressOfOperand) {
   DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(Op);
   return ActOnDeclarationNameExpr(S, OperatorLoc, Name, HasTrailingLParen, &SS,
-                                  /*ForceRes*/false, isAddressOfOperand);
+                                  isAddressOfOperand);
 }
 
 /// ActOnCXXTypeidOfType - Parse typeid( type-id ).