https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102028
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is the template which gets matched:
/**
* @brief Generic inserter for rvalue stream
* @param __os An input stream.
* @param __x A reference to the object being inserted.
* @return __os
*
* This is just a forwarding function to allow insertion to
* rvalue streams since they won't bind to the inserter functions
* that take an lvalue reference.
*/
template<typename _Ostream, typename _Tp>
inline __rvalue_stream_insertion_t<_Ostream, _Tp>
operator<<(_Ostream&& __os, const _Tp& __x)
{
__os << __x;
return std::move(__os);
}
That is the code is same as:
std::stringstream &&a = std::stringstream{};
std::ostream &b = a;
b<<A{};
foo(std::move(a));
The original code is able to compile on GCC, clang (with libc++) and MSVC.
