Test for diagnostic quality improvement in r256049.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@256083 91177308-0d34-0410-b5e6-96231b3b80d8

test/SemaTemplate/class-template-decl.cpp

@@ -152,3 +152,10 @@ void DontCrashOnThis() {
   T &pT = T();
   pT;
 }
+
+namespace abstract_dependent_class {
+  template<typename T> struct A {
+    virtual A<T> *clone() = 0; // expected-note {{pure virtual}}
+  };
+  template<typename T> A<T> *A<T>::clone() { return new A<T>; } // expected-error {{abstract class type 'A<T>'}}
+}