clang/test/SemaTemplate/constraints.cpp

   1 // RUN: %clang_cc1 -std=c++20 -verify %s
   2 // RUN: %clang_cc1 -std=c++20 -verify %s -DDEPENDENT_OR
   3
   4 #ifdef DEPENDENT_OR
   5 // This causes the || below to be a CXXOperatorCallExpr not a BinaryOperator.
   6 struct A {}; bool operator||(A, A);
   7 #endif
   8
   9 namespace PR45589 {
  10   template<typename T> struct X { static constexpr bool value = T::value; }; // expected-error {{cannot be used prior to '::'}}
  11   struct False { static constexpr bool value = false; };
  12   struct True { static constexpr bool value = true; };
  13
  14   template<typename T> concept C = true;
  15
  16   template<bool B, typename T> constexpr int test = 0;
  17   template<bool B, typename T> requires C<T> constexpr int test<B, T> = 1;
  18   template<bool B, typename T> requires (B && C<T>) || (X<T>::value && C<T>) constexpr int test<B, T> = 2; // expected-note {{instantiation of}} expected-note {{while substituting}}
  19   static_assert(test<true, False> == 2);
  20   static_assert(test<true, True> == 2);
  21   static_assert(test<true, char> == 2); // satisfaction of second term of || not considered
  22   static_assert(test<false, False> == 1);
  23   static_assert(test<false, True> == 2); // constraints are partially ordered
  24   static_assert(test<false, char> == 1); // expected-note {{while}} expected-note {{during}}
  25 }