clang/test/Parser/cxx2a-constrained-template-param.cpp

   1 // RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
   2
   3 namespace type
   4 {
   5   template<typename T>
   6   concept C1 = true;
   7
   8   template<C1 T, C1 U = int>
   9   using A = T[10];
  10
  11   using a = A<int>;
  12
  13   namespace ns {
  14     template<typename T, int a = 0>
  15     concept C2 = true;
  16   }
  17
  18   template<ns::C2 T1, ::type::ns::C2 T2> requires (sizeof(T1) <= sizeof(T2))
  19   struct B { };
  20
  21   using b = B<int, int>;
  22
  23   template<ns::C2... T1>
  24   struct C { };
  25
  26   using c1 = C<char, char, char>;
  27   using c2 = C<char, char, char, char>;
  28 }
  29
  30 namespace non_type
  31 {
  32   template<int v>
  33   concept C1 = true;
  34
  35   template<C1 v, C1 u = 0> // expected-error{{expected a type}} // expected-note{{declared here}}
  36   // expected-error@-1 2{{concept named in type constraint is not a type concept}}
  37   // expected-error@-2 {{expected ',' or '>' in template-parameter-list}}
  38   int A = v; // expected-error{{'v' does not refer to a value}}
  39 }
  40
  41 namespace temp
  42 {
  43   template<typename>
  44   struct test1 { }; // expected-note{{template is declared here}}
  45
  46   template<template<typename> typename T>
  47   concept C1 = true;
  48
  49   template<C1 TT, C1 UU = test1> // expected-error{{use of class template 'test1' requires template arguments}}
  50   // expected-error@-1 2{{concept named in type constraint is not a type concept}}
  51   using A = TT<int>; // expected-error{{expected ';' after alias declaration}}
  52 }
  53
  54 namespace PR67235 {
  55
  56 template <class T>
  57 concept C = true;
  58
  59 template <auto D>
  60 struct S {};
  61
  62 // Don't destroy annotation 'C' at the end of the lambda; else we'll run into a
  63 // use-after-free bug while constructing the type constraint 'C' on 'Default'.
  64 template <typename Ret, C Default = decltype([] { return Ret(); })>
  65 void func() {}
  66
  67 template <typename Ret, C Default = S<[] { return Ret(); }>>
  68 void func2() {}
  69
  70 }