clang/test/CXX/class/class.compare/class.compare.default/p3.cpp

   1 // This test is for the [class.compare.default]p3 added by P2002R0
   2 // Also covers modifications made by P2448R2
   3
   4 // RUN: %clang_cc1 -std=c++2a -verify=expected,cxx2a %s
   5 // RUN: %clang_cc1 -std=c++23 -verify=expected %s
   6
   7 namespace std {
   8   struct strong_ordering {
   9     int n;
  10     constexpr operator int() const { return n; }
  11     static const strong_ordering less, equal, greater;
  12   };
  13   constexpr strong_ordering strong_ordering::less = {-1};
  14   constexpr strong_ordering strong_ordering::equal = {0};
  15   constexpr strong_ordering strong_ordering::greater = {1};
  16 }
  17
  18 struct A {
  19   friend bool operator==(const A&, const A&) = default;
  20   friend bool operator!=(const A&, const A&) = default;
  21
  22   friend std::strong_ordering operator<=>(const A&, const A&) = default;
  23   friend bool operator<(const A&, const A&) = default;
  24   friend bool operator<=(const A&, const A&) = default;
  25   friend bool operator>(const A&, const A&) = default;
  26   friend bool operator>=(const A&, const A&) = default;
  27 };
  28 struct TestA {
  29   friend constexpr bool operator==(const A&, const A&) noexcept;
  30   friend constexpr bool operator!=(const A&, const A&) noexcept;
  31
  32   friend constexpr std::strong_ordering operator<=>(const A&, const A&) noexcept;
  33   friend constexpr bool operator<(const A&, const A&);
  34   friend constexpr bool operator<=(const A&, const A&);
  35   friend constexpr bool operator>(const A&, const A&);
  36   friend constexpr bool operator>=(const A&, const A&);
  37 };
  38
  39 // Declaration order doesn't matter, even though the secondary operators need
  40 // to know whether the primary ones are constexpr.
  41 struct ReversedA {
  42   friend bool operator>=(const ReversedA&, const ReversedA&) = default;
  43   friend bool operator>(const ReversedA&, const ReversedA&) = default;
  44   friend bool operator<=(const ReversedA&, const ReversedA&) = default;
  45   friend bool operator<(const ReversedA&, const ReversedA&) = default;
  46   friend std::strong_ordering operator<=>(const ReversedA&, const ReversedA&) = default;
  47
  48   friend bool operator!=(const ReversedA&, const ReversedA&) = default;
  49   friend bool operator==(const ReversedA&, const ReversedA&) = default;
  50 };
  51 struct TestReversedA {
  52   friend constexpr bool operator>=(const ReversedA&, const ReversedA&);
  53   friend constexpr bool operator>(const ReversedA&, const ReversedA&);
  54   friend constexpr bool operator<=(const ReversedA&, const ReversedA&);
  55   friend constexpr bool operator<(const ReversedA&, const ReversedA&);
  56   friend constexpr std::strong_ordering operator<=>(const ReversedA&, const ReversedA&) noexcept;
  57
  58   friend constexpr bool operator!=(const ReversedA&, const ReversedA&) noexcept;
  59   friend constexpr bool operator==(const ReversedA&, const ReversedA&) noexcept;
  60 };
  61
  62 struct B {
  63   A a;
  64   friend bool operator==(const B&, const B&) = default;
  65   friend bool operator!=(const B&, const B&) = default;
  66
  67   friend std::strong_ordering operator<=>(const B&, const B&) = default;
  68   friend bool operator<(const B&, const B&) = default;
  69   friend bool operator<=(const B&, const B&) = default;
  70   friend bool operator>(const B&, const B&) = default;
  71   friend bool operator>=(const B&, const B&) = default;
  72 };
  73 struct TestB {
  74   friend constexpr bool operator==(const B&, const B&) noexcept;
  75   friend constexpr bool operator!=(const B&, const B&) noexcept;
  76
  77   friend constexpr std::strong_ordering operator<=>(const B&, const B&);
  78   friend constexpr bool operator<(const B&, const B&);
  79   friend constexpr bool operator<=(const B&, const B&);
  80   friend constexpr bool operator>(const B&, const B&);
  81   friend constexpr bool operator>=(const B&, const B&);
  82 };
  83
  84 struct C {
  85   friend bool operator==(const C&, const C&); // expected-note {{previous}} \
  86                                               // cxx2a-note 2{{declared here}}
  87   friend bool operator!=(const C&, const C&) = default; // expected-note {{previous}}
  88
  89   friend std::strong_ordering operator<=>(const C&, const C&); // expected-note {{previous}} \
  90                                                                // cxx2a-note 2{{declared here}}
  91   friend bool operator<(const C&, const C&) = default; // expected-note {{previous}}
  92   friend bool operator<=(const C&, const C&) = default; // expected-note {{previous}}
  93   friend bool operator>(const C&, const C&) = default; // expected-note {{previous}}
  94   friend bool operator>=(const C&, const C&) = default; // expected-note {{previous}}
  95 };
  96 struct TestC {
  97   friend constexpr bool operator==(const C&, const C&); // expected-error {{non-constexpr}}
  98   friend constexpr bool operator!=(const C&, const C&); // expected-error {{non-constexpr}}
  99
 100   friend constexpr std::strong_ordering operator<=>(const C&, const C&); // expected-error {{non-constexpr}}
 101   friend constexpr bool operator<(const C&, const C&); // expected-error {{non-constexpr}}
 102   friend constexpr bool operator<=(const C&, const C&); // expected-error {{non-constexpr}}
 103   friend constexpr bool operator>(const C&, const C&); // expected-error {{non-constexpr}}
 104   friend constexpr bool operator>=(const C&, const C&); // expected-error {{non-constexpr}}
 105 };
 106
 107 struct D {
 108   A a;
 109   C c;
 110   A b;
 111   friend bool operator==(const D&, const D&) = default; // expected-note {{previous}}
 112   friend bool operator!=(const D&, const D&) = default; // expected-note {{previous}}
 113
 114   friend std::strong_ordering operator<=>(const D&, const D&) = default; // expected-note {{previous}}
 115   friend bool operator<(const D&, const D&) = default; // expected-note {{previous}}
 116   friend bool operator<=(const D&, const D&) = default; // expected-note {{previous}}
 117   friend bool operator>(const D&, const D&) = default; // expected-note {{previous}}
 118   friend bool operator>=(const D&, const D&) = default; // expected-note {{previous}}
 119 };
 120 struct TestD {
 121   friend constexpr bool operator==(const D&, const D&); // expected-error {{non-constexpr}}
 122   friend constexpr bool operator!=(const D&, const D&); // expected-error {{non-constexpr}}
 123
 124   friend constexpr std::strong_ordering operator<=>(const D&, const D&); // expected-error {{non-constexpr}}
 125   friend constexpr bool operator<(const D&, const D&); // expected-error {{non-constexpr}}
 126   friend constexpr bool operator<=(const D&, const D&); // expected-error {{non-constexpr}}
 127   friend constexpr bool operator>(const D&, const D&); // expected-error {{non-constexpr}}
 128   friend constexpr bool operator>=(const D&, const D&); // expected-error {{non-constexpr}}
 129 };
 130
 131
 132 struct E {
 133   A a;
 134   C c; // cxx2a-note 2{{non-constexpr comparison function would be used to compare member 'c'}}
 135   A b;
 136   friend constexpr bool operator==(const E&, const E&) = default; // cxx2a-error {{cannot be declared constexpr}}
 137   friend constexpr bool operator!=(const E&, const E&) = default;
 138
 139   friend constexpr std::strong_ordering operator<=>(const E&, const E&) = default; // cxx2a-error {{cannot be declared constexpr}}
 140   friend constexpr bool operator<(const E&, const E&) = default;
 141   friend constexpr bool operator<=(const E&, const E&) = default;
 142   friend constexpr bool operator>(const E&, const E&) = default;
 143   friend constexpr bool operator>=(const E&, const E&) = default;
 144 };
 145
 146 struct E2 : A, C { // cxx2a-note 2{{non-constexpr comparison function would be used to compare base class 'C'}}
 147   friend constexpr bool operator==(const E2&, const E2&) = default; // cxx2a-error {{cannot be declared constexpr}}
 148   friend constexpr bool operator!=(const E2&, const E2&) = default;
 149
 150   friend constexpr std::strong_ordering operator<=>(const E2&, const E2&) = default; // cxx2a-error {{cannot be declared constexpr}}
 151   friend constexpr bool operator<(const E2&, const E2&) = default;
 152   friend constexpr bool operator<=(const E2&, const E2&) = default;
 153   friend constexpr bool operator>(const E2&, const E2&) = default;
 154   friend constexpr bool operator>=(const E2&, const E2&) = default;
 155 };
 156
 157 struct F {
 158   friend bool operator==(const F&, const F&); // cxx2a-note {{declared here}}
 159   friend constexpr bool operator!=(const F&, const F&) = default; // cxx2a-error {{cannot be declared constexpr}}
 160
 161   friend std::strong_ordering operator<=>(const F&, const F&); // cxx2a-note 4{{non-constexpr comparison function declared here}}
 162   friend constexpr bool operator<(const F&, const F&) = default; // cxx2a-error {{cannot be declared constexpr}}
 163   friend constexpr bool operator<=(const F&, const F&) = default; // cxx2a-error {{cannot be declared constexpr}}
 164   friend constexpr bool operator>(const F&, const F&) = default; // cxx2a-error {{cannot be declared constexpr}}
 165   friend constexpr bool operator>=(const F&, const F&) = default; // cxx2a-error {{cannot be declared constexpr}}
 166 };
 167
 168 // No implicit 'constexpr' if it's not the first declaration.
 169 // FIXME: This rule creates problems for reordering of declarations; is this
 170 // really the right model?
 171 struct G;
 172 bool operator==(const G&, const G&); // expected-note {{previous declaration}}
 173 bool operator!=(const G&, const G&); // expected-note {{previous declaration}}
 174 std::strong_ordering operator<=>(const G&, const G&); // expected-note {{previous declaration}}
 175 bool operator<(const G&, const G&); // expected-note {{previous declaration}}
 176 bool operator<=(const G&, const G&); // expected-note {{previous declaration}}
 177 bool operator>(const G&, const G&); // expected-note {{previous declaration}}
 178 bool operator>=(const G&, const G&); // expected-note {{previous declaration}}
 179 struct G {
 180   friend bool operator==(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 181   friend bool operator!=(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 182
 183   friend std::strong_ordering operator<=>(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 184   friend bool operator<(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 185   friend bool operator<=(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 186   friend bool operator>(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 187   friend bool operator>=(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 188 };
 189 bool operator==(const G&, const G&);
 190 bool operator!=(const G&, const G&);
 191
 192 std::strong_ordering operator<=>(const G&, const G&);
 193 bool operator<(const G&, const G&);
 194 bool operator<=(const G&, const G&);
 195 bool operator>(const G&, const G&);
 196 bool operator>=(const G&, const G&);
 197
 198 namespace PR44721 {
 199   template <typename T> bool operator==(T const &, T const &) { return true; }
 200   template <typename T, typename U> bool operator!=(T const &, U const &) { return true; }
 201   template <typename T> int operator<=>(T const &, T const &) { return 0; }
 202
 203   struct S {
 204     friend bool operator==(const S &, const S &) = default;
 205     friend bool operator<=>(const S &, const S &) = default;
 206     int x;
 207   };
 208 }