clang/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p7-cxx20.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify %s
   2 // RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify %s
   3
   4 // p1099 'using SCOPEDENUM::MEMBER;'
   5
   6 namespace Zero {
   7 namespace Bob {
   8 enum class Kevin {
   9   Stuart,
  10   AlsoStuart
  11 #if __cplusplus >= 202002L
  12 // expected-note@-3{{target of using declaration}}
  13 // expected-note@-3{{target of using declaration}}
  14 #endif
  15 };
  16 } // namespace Bob
  17
  18 using Bob::Kevin::Stuart;
  19 #if __cplusplus < 202002L
  20 // expected-warning@-2{{using declaration naming a scoped enumerator is a C++20 extension}}
  21 #else
  22 using Bob::Kevin::Stuart;
  23
  24 auto b = Stuart;
  25
  26 namespace Foo {
  27 int Stuart;               // expected-note{{conflicting declaration}}
  28 using Bob::Kevin::Stuart; // expected-error{{target of using declaration conflicts}}
  29
  30 using Bob::Kevin::AlsoStuart; // expected-note{{using declaration}}
  31 int AlsoStuart;               // expected-error{{declaration conflicts with target}}
  32 } // namespace Foo
  33 #endif
  34
  35 } // namespace Zero
  36
  37 namespace One {
  38
  39 // derived from [namespace.udecl]/3
  40 enum class button { up,
  41                     down };
  42 struct S {
  43   using button::up;
  44 #if __cplusplus < 202002L
  45   // expected-warning@-2{{a C++20 extension}}
  46   // expected-error@-3{{using declaration in class}}
  47 #else
  48   button b = up;
  49 #endif
  50 };
  51
  52 #if __cplusplus >= 202002L
  53 // some more
  54 struct T : S {
  55   button c = up;
  56 };
  57 #endif
  58 enum E2 { e2 };
  59 } // namespace One
  60
  61 namespace Two {
  62 enum class E1 { e1 };
  63
  64 struct S {
  65   using One::e2;
  66 #if __cplusplus < 202002L
  67   // expected-error@-2{{using declaration in class}}
  68 #else
  69   One::E2 c = e2;
  70 #endif
  71 };
  72
  73 } // namespace Two
  74
  75 namespace Three {
  76
  77 enum E3 { e3 };
  78 struct e3;
  79
  80 struct S {
  81   using Three::e3; // expected-error{{using declaration in class}}
  82
  83   enum class E4 { e4 };
  84   enum E5 { e5 };
  85 };
  86
  87 using S::e5;
  88 using S::E4::e4;
  89 #if __cplusplus < 202002L
  90 // expected-error@-3{{using declaration cannot refer to class member}}
  91 // expected-note@-4{{use a constexpr variable instead}}
  92 // expected-warning@-4{{a C++20 extension}}
  93 // expected-error@-5{{using declaration cannot refer to class member}}
  94 // expected-note@-6{{use a constexpr variable instead}}
  95 #else
  96 auto a = e4;
  97 auto b = e5;
  98 #endif
  99 } // namespace Three
 100
 101 namespace Four {
 102
 103 template <typename T>
 104 struct TPL {
 105   enum class E1 { e1 };
 106   struct IN {
 107     enum class E2 { e2 };
 108   };
 109
 110 protected:
 111   enum class E3 { e3 }; // expected-note{{declared protected here}}
 112 };
 113
 114 using TPL<int>::E1::e1;
 115 #if __cplusplus < 202002L
 116 // expected-warning@-2{{a C++20 extension}}
 117 // expected-error@-3{{using declaration cannot refer to class member}}
 118 // expected-note@-4{{use a constexpr variable instead}}
 119 #else
 120 using TPL<float>::IN::E2::e2;
 121
 122 auto a = e1;
 123 auto b = e2;
 124 #endif
 125
 126 enum class E4 { e4 };
 127 template <typename T>
 128 struct DER : TPL<int> {
 129   using TPL<T>::E1::e1;
 130 #if __cplusplus < 202002L
 131   // expected-warning@-2{{a C++20 extension}}
 132   // expected-warning@-3{{using declaration naming a scoped}}
 133   // expected-error@-4{{which is not a base}}
 134 #endif
 135   using TPL<T>::E3::e3; // expected-error{{is a protected member}}
 136 #if __cplusplus < 202002L
 137   // expected-warning@-2 2{{using declaration naming a scoped}}
 138   // expected-error@-3{{which is not a base}}
 139 #endif
 140
 141   using E4::e4;
 142 #if __cplusplus < 202002L
 143   // expected-warning@-2{{a C++20 extension}}
 144   // expected-error@-3{{which is not a class}}
 145 #else
 146   auto Foo() { return e1; }
 147   auto Bar() { return e2; }
 148 #endif
 149 };
 150
 151 DER<float> x; // expected-note{{requested here}}
 152 DER<int> y;
 153 #if __cplusplus < 202002L
 154 // expected-note@-2{{requested here}}
 155 #else
 156 auto y1 = y.Foo();
 157 auto y2 = y.Bar();
 158 #endif
 159 } // namespace Four
 160
 161 namespace Five {
 162 template <unsigned I, unsigned K>
 163 struct Quux {
 164   enum class Q : unsigned; // expected-note{{member is declared here}}
 165   enum class R : unsigned { i = I,
 166                             k = K };
 167 };
 168
 169 using Quux<1, 2>::Q::nothing; // expected-error{{implicit instantiation of undefined}}
 170 using Quux<1, 2>::R::i;
 171 #if __cplusplus < 202002L
 172 // expected-warning@-2{{a C++20 extension}}
 173 // expected-error@-3{{using declaration cannot refer to class member}}
 174 // expected-note@-4{{use a constexpr variable instead}}
 175 #endif
 176
 177 } // namespace Five
 178
 179 namespace Six {
 180 template <unsigned I, unsigned K>
 181 struct Quux {
 182   enum class Q : unsigned; // expected-note{{member is declared here}}
 183   enum class R : unsigned { i = I,
 184                             k = K };
 185 };
 186
 187 template <unsigned I> struct Fido {
 188   using Quux<I, I>::Q::nothing; // expected-error{{implicit instantiation of undefined}}
 189 };
 190
 191 Fido<2> a; // expected-note{{in instantiation}}
 192
 193 } // namespace Six
 194
 195 namespace Seven {
 196 template <unsigned I, unsigned K>
 197 struct Quux {
 198   enum class R : unsigned { i = I,
 199                             k = K };
 200 };
 201
 202 template <unsigned I> struct Toto {
 203   using Quux<I, I>::R::i;
 204 #if __cplusplus < 202002L
 205   // expected-warning@-2{{a C++20 extension}}
 206 // expected-error@-3{{refers into}}
 207 #else
 208   static_assert(unsigned(i) == I);
 209 #endif
 210 };
 211
 212 Toto<2> b;
 213 #if __cplusplus < 202002L
 214 // expected-note@-2{{in instantiation}}
 215 #endif
 216
 217 } // namespace Seven
 218
 219 namespace Eight {
 220 struct Kevin {
 221   enum class B { a };
 222   enum a {};
 223 };
 224
 225 using Kevin::B::a;
 226 #if __cplusplus < 202002L
 227 // expected-warning@-2{{a C++20 extension}}
 228 // expected-error@-3{{using declaration cannot refer to class member}}
 229 // expected-note@-4{{use a constexpr variable instead}}
 230 #endif
 231 using Kevin::B::a;
 232 #if __cplusplus < 202002L
 233 // expected-warning@-2{{a C++20 extension}}
 234 // expected-error@-3{{using declaration cannot refer to class member}}
 235 // expected-note@-4{{use a constexpr variable instead}}
 236 #endif
 237
 238 class X : Kevin {
 239   using Kevin::B::a; // expected-note{{previous using declaration}}
 240 #if __cplusplus < 202002L
 241 // expected-warning@-2{{a C++20 extension}}
 242 #endif
 243   using Kevin::a;
 244   using Kevin::B::a; // expected-error{{redeclaration of using declaration}}
 245 };
 246
 247 } // namespace Eight
 248
 249 namespace Nine {
 250 namespace Q {
 251 enum class Bob { a };
 252 using Bob::a;
 253 #if __cplusplus < 202002L
 254 // expected-warning@-2{{a C++20 extension}}
 255 #endif
 256 } // namespace Q
 257
 258 using Q::a;
 259 using Q::Bob::a;
 260 #if __cplusplus < 202002L
 261 // expected-warning@-2{{a C++20 extension}}
 262 #endif
 263
 264 #if __cplusplus >= 202002L
 265 struct Foo {
 266   using Q::a; // expected-note{{previous using declaration}}
 267   using Q::Bob::a;
 268   using Q::a; // expected-error{{redeclaration of using declaration}}
 269 };
 270 #endif
 271 } // namespace Nine