clang/test/SemaTemplate/explicit-instantiation-cxx20.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++20  %s
   2
   3 template<class T>
   4 concept C = true;
   5
   6 template<class T>
   7 concept D = C<T> && true;
   8
   9 template<typename T>
  10 struct a {
  11     void no_candidate() requires(false) {}
  12     // expected-note@-1 {{candidate function not viable: constraints not satisfied}} \
  13     // expected-note@-1 {{because 'false' evaluated to false}}
  14     void no_candidate() requires(false && false) {}
  15     // expected-note@-1 {{candidate function not viable: constraints not satisfied}} \
  16     // expected-note@-1 {{because 'false' evaluated to false}}
  17
  18     void subsumes();
  19     void subsumes() requires C<T>;
  20     void subsumes() requires D<T> {};
  21
  22     void ok() requires false;
  23     void ok() requires true {};
  24
  25     void ok2() requires false;
  26     void ok2(){};
  27
  28     void ambiguous() requires true;
  29     // expected-note@-1 {{candidate function}}
  30     void ambiguous() requires C<T>;
  31     // expected-note@-1 {{candidate function}}
  32 };
  33 template void a<int>::no_candidate();
  34 // expected-error@-1 {{no viable candidate for explicit instantiation of 'no_candidate'}}
  35
  36 template void a<int>::ambiguous();
  37 // expected-error@-1 {{partial ordering for explicit instantiation of 'ambiguous' is ambiguous}}
  38
  39 template void a<int>::ok();
  40 template void a<int>::ok2();