std::meta::exception(C++26)

namespace std::meta {
  class exception : public std::exception {
  public:
    consteval exception(std::u8string_view what, info from,
                        std::source_location where = std::source_location::current()) noexcept;

    consteval exception(std::string_view what, info from,
                        std::source_location where = std::source_location::current()) noexcept;

    exception(const exception&) = default;
    exception(exception&&) = default;

    exception& operator=(const exception&) = default;
    exception& operator=(exception&&) = default;

    consteval const char* what() const noexcept override;
    consteval std::u8string_view u8what() const noexcept;
    consteval info from() const noexcept;
    consteval std::source_location where() const noexcept;
  };
}