[Sema] Diagnose use of declaration correctly.

Before we skipped that for virtual functions not fully qualified (r81507).
This commit basically reverts this to the older behaviour, which seems
more consistent. We now also correctly consider ill-formed calls to deleted
member functions, which were silently passed before in some cases.
The review contains the whole discussion.

PR:		20268
Differential Revision:	 http://reviews.llvm.org/D11334

llvm-svn: 242857
diff --git a/clang/test/SemaCXX/deleted-function-access.cpp b/clang/test/SemaCXX/deleted-function-access.cpp
new file mode 100644
index 0000000..f355e41
--- /dev/null
+++ b/clang/test/SemaCXX/deleted-function-access.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
+
+struct S {
+    virtual void f() = delete; //expected-note{{'f' has been explicitly marked deleted here}}
+    void g() { f(); } //expected-error{{attempt to use a deleted function}}
+};