llvm/clang/test/Modules/Inputs/merge-template-pattern-visibility/c.h

namespace CrossModuleMerge {
  template<typename, typename = int> struct A;
  template<typename T> struct B;

  template<typename, typename> struct A {};
  template<typename T> struct B : A<T> {};
  template<typename T> inline auto C(T) {}
}