clang/test/SemaCXX/pr98102.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 %s
   2 // expected-no-diagnostics
   3
   4 template <bool v>
   5 struct BC {
   6   static constexpr bool value = v;
   7 };
   8
   9 template <typename T, typename Arg>
  10 struct Constructible : BC<__is_constructible(T, Arg)> {};
  11
  12 template <typename T>
  13 using Requires = T::value;
  14
  15 template <typename T>
  16 struct optional {
  17   template <typename U, Requires<Constructible<T, U>> = true>
  18   optional(U) {}
  19 };
  20
  21 struct MO {};
  22 struct S : MO {};
  23 struct TB {
  24   TB(optional<S>) {}
  25 };
  26
  27 class TD : TB, MO {
  28   using TB::TB;
  29 };
  30
  31 void foo() {
  32   static_assert(Constructible<TD, TD>::value);
  33 }