clang/test/CXX/temp/temp.constr/temp.constr.order/var-template-partial-specializations.cpp

   1 // RUN: %clang_cc1 -std=c++2a -x c++ -verify %s
   2
   3 template<typename T> requires (sizeof(T) >= 4)
   4 // expected-note@-1{{similar constraint expressions not considered equivalent}}
   5 bool a = false; // expected-note{{template is declared here}}
   6
   7 template<typename T> requires (sizeof(T) >= 4 && sizeof(T) <= 10)
   8 // expected-note@-1{{similar constraint expression here}}
   9 bool a<T> = true; // expected-error{{variable template partial specialization is not more specialized than the primary template}}
  10
  11 template<typename T>
  12 concept C1 = sizeof(T) >= 4;
  13
  14 template<typename T> requires C1<T>
  15 bool b = false;
  16
  17 template<typename T> requires (C1<T> && sizeof(T) <= 10)
  18 bool b<T> = true;
  19
  20 template<typename T>
  21 concept C2 = sizeof(T) > 1 && sizeof(T) <= 8;
  22
  23 template<typename T>
  24 bool c = false;
  25
  26 template<typename T> requires C1<T>
  27 bool c<T> = true;
  28
  29 template<typename T>
  30 bool d = false;
  31
  32 template<typename T>
  33 bool d<T> = true; // expected-error{{variable template partial specialization does not specialize any template argument; to define the primary template, remove the template argument list}}
  34
  35 template<typename T> requires C1<T>
  36 bool e = false;
  37
  38 template<typename T>
  39 bool e<T> = true; // expected-error{{variable template partial specialization does not specialize any template argument; to define the primary template, remove the template argument list}}
  40
  41 template<typename T>
  42 constexpr int f = 1;
  43
  44 template<typename T> requires C1<T> && C2<T>
  45 constexpr int f<T> = 2;
  46
  47 template<typename T> requires C1<T> || C2<T>
  48 constexpr int f<T> = 3;
  49
  50 static_assert(f<unsigned> == 2);
  51 static_assert(f<char[10]> == 3);
  52 static_assert(f<char> == 1);
  53
  54 template <int I>
  55 struct S {
  56   template <typename T>
  57   static constexpr int f = 1;
  58
  59   template <typename T>
  60     requires C1<T> && C2<T>
  61   static constexpr int f<T> = 2;
  62
  63   template <typename T>
  64     requires C1<T> || C2<T>
  65   static constexpr int f<T> = 3;
  66 };
  67
  68 static_assert(S<1>::f<unsigned> == 2);
  69 static_assert(S<1>::f<char[10]> == 3);
  70 static_assert(S<1>::f<char> == 1);