gcc/testsuite/g++.dg/cpp23/subscript15.C

   1 // PR c++/111493
   2 // { dg-do compile { target c++23 } }
   3
   4 template<class T, class... Ts>
   5 concept CartesianIndexable = requires(T t, Ts... ts) { t[ts...]; };
   6
   7 static_assert(!CartesianIndexable<int>);
   8 static_assert(!CartesianIndexable<int, int>);
   9 static_assert(!CartesianIndexable<int, int, int>);
  10
  11 static_assert(!CartesianIndexable<int*>);
  12 static_assert(CartesianIndexable<int*, int>);
  13 static_assert(!CartesianIndexable<int*, int, int>);
  14 static_assert(!CartesianIndexable<int*, int*>);
  15
  16 template<class... Ts>
  17 struct A {
  18   void operator[](Ts...);
  19 };
  20
  21 static_assert(!CartesianIndexable<A<>, int>);
  22 static_assert(CartesianIndexable<A<int>, int>);
  23 static_assert(!CartesianIndexable<A<int>>);
  24 static_assert(!CartesianIndexable<A<int>, int, int>);
  25 static_assert(CartesianIndexable<A<int, int>, int, int>);