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) {}

inline void f() {
  B<int> bi;
  C(0);
}

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) {}
}