clang/test/Parser/cxx2a-constrained-template-param-with-partial-id.cpp

   1 // RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
   2
   3 template<typename T, int a>
   4 concept C1 = true;
   5
   6 template<C1 T>
   7 // expected-error@-1 {{'C1' requires more than 1 template argument; provide the remaining arguments explicitly to use it here}}
   8 using badA = T[10];
   9
  10 template<C1<0> T>
  11 using A = T[10];
  12
  13 using a = A<int>;
  14
  15 namespace ns {
  16   template<typename T, typename U, typename... X>
  17   concept C2 = true;
  18 }
  19
  20 template<ns::C2 T1, ::ns::C2 T2>
  21 // expected-error@-1 2{{'C2' requires more than 1 template argument; provide the remaining arguments explicitly to use it here}}
  22 requires (sizeof(T1) <= sizeof(T2))
  23 struct badB { };
  24
  25 template<ns::C2<int> T1, ::ns::C2<char, T1> T2>
  26   requires (sizeof(T1) <= sizeof(T2))
  27 struct B { };
  28
  29 using b = B<int, int>;
  30
  31 template<ns::C2... T1>
  32 // expected-error@-1 {{'C2' requires more than 1 template argument; provide the remaining arguments explicitly to use it here}}
  33 struct badC { };
  34
  35 template<ns::C2<int>... T1>
  36 struct C { };
  37
  38 using c1 = C<char, char, char>;
  39 using c2 = C<char, char, char, char>;