Implement template instantiation for using directives, which is dead simple.

Also, make the "don't know how to instantiate a particular kind of
declaration" diagnostic nicer, so we don't have to trap Clang in a
debugger to figure out what went wrong.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89050 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaTemplate/instantiate-using-decl.cpp b/test/SemaTemplate/instantiate-using-decl.cpp
index fd9010f..a1cf355 100644
--- a/test/SemaTemplate/instantiate-using-decl.cpp
+++ b/test/SemaTemplate/instantiate-using-decl.cpp
@@ -1,5 +1,7 @@
 // RUN: clang-cc -fsyntax-only -verify %s
 
+namespace N { }
+
 template<typename T>
 struct A {
   void f();
@@ -10,6 +12,7 @@
   using A<T>::f;
   
   void g() {
+    using namespace N;
     f();
   }
 };