🥅 Better error messages when tuple indexing fails

include/cib/tuple.hpp

@@ -222,6 +222,8 @@ struct index_pair {
  std::size_t inner;
 };
 
+template <typename...> constexpr auto always_false_v = false;
+
 template <std::size_t... Is, template <typename> typename... Fs, typename... Ts>
 struct tuple_impl<std::index_sequence<Is...>, index_function_list<Fs...>, Ts...>
  : element_helper<Fs...>::template element_t<Is, Ts>... {
@@ -269,19 +271,35 @@ struct tuple_impl<std::index_sequence<Is...>, index_function_list<Fs...>, Ts...>
  template <std::size_t I>
  [[nodiscard]] constexpr auto
  operator[](index_constant<I> *i) const & -> decltype(auto) {
+ static_assert(I < sizeof...(Ts), "Tuple index out of bounds!");
  return this->ugly_iGet_clvr(i);
  }
  template <std::size_t I>
  [[nodiscard]] constexpr auto
  operator[](index_constant<I> *i) & -> decltype(auto) {
+ static_assert(I < sizeof...(Ts), "Tuple index out of bounds!");
  return this->ugly_iGet_lvr(i);
  }
  template <std::size_t I>
  [[nodiscard]] constexpr auto
  operator[](index_constant<I> *i) && -> decltype(auto) {
+ static_assert(I < sizeof...(Ts), "Tuple index out of bounds!");
  return std::move(*this).ugly_iGet_rvr(i);
  }
 
+ constexpr auto ugly_tGet_clvr(auto idx) const & -> void {
+ static_assert(always_false_v<decltype(idx), Ts...>,
+ "Type not found in tuple!");
+ }
+ constexpr auto ugly_tGet_lvr(auto idx) & -> void {
+ static_assert(always_false_v<decltype(idx), Ts...>,
+ "Type not found in tuple!");
+ }
+ constexpr auto ugly_tGet_rvr(auto idx) && -> void {
+ static_assert(always_false_v<decltype(idx), Ts...>,
+ "Type not found in tuple!");
+ }
+
  [[nodiscard]] constexpr auto get(auto idx) const & -> decltype(auto) {
  return this->ugly_tGet_clvr(idx);
  }