llvm/clang/test/Modules/Inputs/PR27699/streambuf

 #ifndef STREAMBUF
 #define STREAMBUF
 template <typename> struct basic_streambuf {
  basic_streambuf(const basic_streambuf &);
  };
template <typename T> basic_streambuf<T>::basic_streambuf(const basic_streambuf &) = default;
#endif