[Bug c++/118698] [14/15 Regression] Compiler ICE on concept code accepted by MSVC and clang

[ppalka at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118698

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |ppalka at gcc dot gnu.org

--- Comment #8 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Started with r14-9938, though I bet before this commit it only accidentally
worked.

A workaround is to use an intermediate variable template:

template <typename T, template <typename...> typename U>
inline constexpr bool is_specialization_of_v =
std::invocable<decltype([]<typename... Args>( U<Args...> const& ) { }),T>;

template <typename T, template <typename...> typename U>
concept is_specialization_of = is_specialization_of_v<T, U>;