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 and extension warnings
   3
   4 // RUN: %clang_cc1 -std=c++2a -verify %s
   5 // RUN: %clang_cc1 -std=c++2a -Wc++23-default-comp-relaxed-constexpr -verify=expected,extension %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}} extension-note 2{{non-constexpr comparison function declared here}}
  86   friend bool operator!=(const C&, const C&) = default; // expected-note {{previous}}
  87
  88   friend std::strong_ordering operator<=>(const C&, const C&); // expected-note {{previous}} extension-note 2{{non-constexpr comparison function declared here}}
  89   friend bool operator<(const C&, const C&) = default; // expected-note {{previous}}
  90   friend bool operator<=(const C&, const C&) = default; // expected-note {{previous}}
  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 };
  94 struct TestC {
  95   friend constexpr bool operator==(const C&, const C&); // expected-error {{non-constexpr}}
  96   friend constexpr bool operator!=(const C&, const C&); // expected-error {{non-constexpr}}
  97
  98   friend constexpr std::strong_ordering operator<=>(const C&, const C&); // expected-error {{non-constexpr}}
  99   friend constexpr bool operator<(const C&, const C&); // expected-error {{non-constexpr}}
 100   friend constexpr bool 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 };
 104
 105 struct D {
 106   A a;
 107   C c;
 108   A b;
 109   friend bool operator==(const D&, const D&) = default; // expected-note {{previous}}
 110   friend bool operator!=(const D&, const D&) = default; // expected-note {{previous}}
 111
 112   friend std::strong_ordering operator<=>(const D&, const D&) = default; // expected-note {{previous}}
 113   friend bool operator<(const D&, const D&) = default; // expected-note {{previous}}
 114   friend bool 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 };
 118 struct TestD {
 119   friend constexpr bool operator==(const D&, const D&); // expected-error {{non-constexpr}}
 120   friend constexpr bool operator!=(const D&, const D&); // expected-error {{non-constexpr}}
 121
 122   friend constexpr std::strong_ordering operator<=>(const D&, const D&); // expected-error {{non-constexpr}}
 123   friend constexpr bool operator<(const D&, const D&); // expected-error {{non-constexpr}}
 124   friend constexpr bool 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 };
 128
 129
 130 struct E {
 131   A a;
 132   C c; // extension-note 2{{non-constexpr comparison function would be used to compare member 'c'}}
 133   A b;
 134   friend constexpr bool operator==(const E&, const E&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 135   friend constexpr bool operator!=(const E&, const E&) = default;
 136
 137   friend constexpr std::strong_ordering operator<=>(const E&, const E&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 138   friend constexpr bool operator<(const E&, const E&) = default;
 139   friend constexpr bool operator<=(const E&, const E&) = default;
 140   friend constexpr bool operator>(const E&, const E&) = default;
 141   friend constexpr bool operator>=(const E&, const E&) = default;
 142 };
 143
 144 struct E2 : A, C { // extension-note 2{{non-constexpr comparison function would be used to compare base class 'C'}}
 145   friend constexpr bool operator==(const E2&, const E2&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 146   friend constexpr bool operator!=(const E2&, const E2&) = default;
 147
 148   friend constexpr std::strong_ordering operator<=>(const E2&, const E2&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 149   friend constexpr bool operator<(const E2&, const E2&) = default;
 150   friend constexpr bool operator<=(const E2&, const E2&) = default;
 151   friend constexpr bool operator>(const E2&, const E2&) = default;
 152   friend constexpr bool operator>=(const E2&, const E2&) = default;
 153 };
 154
 155 struct F {
 156   friend bool operator==(const F&, const F&); // extension-note {{non-constexpr comparison function declared here}}
 157   friend constexpr bool operator!=(const F&, const F&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 158
 159   friend std::strong_ordering operator<=>(const F&, const F&); // extension-note 4{{non-constexpr comparison function declared here}}
 160   friend constexpr bool operator<(const F&, const F&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 161   friend constexpr bool operator<=(const F&, const F&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 162   friend constexpr bool operator>(const F&, const F&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 163   friend constexpr bool operator>=(const F&, const F&) = default; // extension-warning {{declared constexpr but invokes a non-constexpr comparison function is a C++23 extension}}
 164 };
 165
 166 // No implicit 'constexpr' if it's not the first declaration.
 167 // FIXME: This rule creates problems for reordering of declarations; is this
 168 // really the right model?
 169 struct G;
 170 bool operator==(const G&, const G&); // expected-note {{previous declaration}}
 171 bool operator!=(const G&, const G&); // expected-note {{previous declaration}}
 172 std::strong_ordering operator<=>(const G&, const G&); // expected-note {{previous declaration}}
 173 bool operator<(const G&, const G&); // expected-note {{previous declaration}}
 174 bool 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 struct G {
 178   friend bool operator==(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 179   friend bool operator!=(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 180
 181   friend std::strong_ordering operator<=>(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 182   friend bool operator<(const G&, const G&) = default; // expected-error {{because it was already declared outside}}
 183   friend bool 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 };
 187 bool operator==(const G&, const G&);
 188 bool operator!=(const G&, const G&);
 189
 190 std::strong_ordering operator<=>(const G&, const G&);
 191 bool operator<(const G&, const G&);
 192 bool operator<=(const G&, const G&);
 193 bool operator>(const G&, const G&);
 194 bool operator>=(const G&, const G&);
 195
 196 namespace PR44721 {
 197   template <typename T> bool operator==(T const &, T const &) { return true; }
 198   template <typename T, typename U> bool operator!=(T const &, U const &) { return true; }
 199   template <typename T> int operator<=>(T const &, T const &) { return 0; }
 200
 201   struct S {
 202     friend bool operator==(const S &, const S &) = default;
 203     friend bool operator<=>(const S &, const S &) = default;
 204     int x;
 205   };
 206 }