gcc/testsuite/g++.dg/template/sfinae10.C

   1 // DR 339
   2 //
   3 // Test of the use of various unary operators with SFINAE
   4
   5 // Boilerplate helpers
   6 typedef char yes_type;
   7 struct no_type { char data[2]; };
   8
   9 template<typename T> T create_a();
  10 template<typename T> struct type { };
  11
  12 template<bool, typename T = void> struct enable_if { typedef T type; };
  13 template<typename T> struct enable_if<false, T> { };
  14
  15 #define JOIN( X, Y ) DO_JOIN( X, Y )
  16 #define DO_JOIN( X, Y ) DO_JOIN2(X,Y)
  17 #define DO_JOIN2( X, Y ) X##Y
  18
  19 #define DEFINE_PREFIX_UNARY_TRAIT(Name,Op)                      \
  20 template<typename T>                                            \
  21   typename enable_if<(sizeof(Op create_a<T>(), 1) > 0),         \
  22                      yes_type>::type                            \
  23   JOIN(check_,Name)(int);                                       \
  24                                                                 \
  25 template<typename T>                                            \
  26   no_type JOIN(check_,Name)(...);                               \
  27                                                                 \
  28 template<typename T>                                            \
  29 struct Name                                                     \
  30 {                                                               \
  31   static const bool value =                                     \
  32     (sizeof(JOIN(check_,Name)<T&>(0)) == sizeof(yes_type));     \
  33 }
  34
  35 #define DEFINE_POSTFIX_UNARY_TRAIT(Name,Op)                     \
  36 template<typename T>                                            \
  37   typename enable_if<(sizeof(create_a<T>() Op, 1) > 0),         \
  38                      yes_type>::type                            \
  39   JOIN(check_,Name)(int);                                       \
  40                                                                 \
  41 template<typename T>                                            \
  42   no_type JOIN(check_,Name)(...);                               \
  43                                                                 \
  44 template<typename T>                                            \
  45 struct Name                                                     \
  46 {                                                               \
  47   static const bool value =                                     \
  48     (sizeof(JOIN(check_,Name)<T&>(0)) == sizeof(yes_type));     \
  49 }
  50
  51 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  52 #  define STATIC_ASSERT(Expr) static_assert(Expr, #Expr)
  53 #else
  54 #  define STATIC_ASSERT(Expr) int JOIN(a,__LINE__)[Expr? 1 : -1]
  55 #endif
  56
  57 struct W {
  58   W operator+();
  59   W operator-();
  60   int operator*();
  61   W operator~();
  62   bool operator!();
  63   W& operator++();
  64   W& operator--();
  65   W& operator++(int);
  66   W& operator--(int);
  67 };
  68
  69 struct X { };
  70 X operator+(X);
  71 X operator-(X);
  72 int operator*(X);
  73 X operator~(X);
  74 bool operator!(X);
  75 X& operator++(X&);
  76 X& operator--(X&);
  77 X& operator++(X&, int);
  78 X& operator--(X&, int);
  79
  80 struct Y { };
  81
  82 struct Z {
  83 private:
  84   Z operator+(); // { dg-error "is private" }
  85   Z operator-(); // { dg-error "is private" }
  86   int operator*(); // { dg-error "is private" }
  87   Z operator~(); // { dg-error "is private" }
  88   bool operator!(); // { dg-error "is private" }
  89   Z& operator++(); // { dg-error "is private" }
  90   Z& operator--(); // { dg-error "is private" }
  91   Z& operator++(int); // { dg-error "is private" }
  92   Z& operator--(int); // { dg-error "is private" }
  93 };
  94
  95 // has_unary_plus
  96 DEFINE_PREFIX_UNARY_TRAIT(has_unary_plus, +); // { dg-error "within this context" }
  97 STATIC_ASSERT((has_unary_plus<int>::value));
  98 STATIC_ASSERT((!has_unary_plus<int X::*>::value));
  99 STATIC_ASSERT((has_unary_plus<W>::value));
 100 STATIC_ASSERT((has_unary_plus<X>::value));
 101 STATIC_ASSERT((!has_unary_plus<Y>::value));
 102
 103 // is_negatable
 104 DEFINE_PREFIX_UNARY_TRAIT(is_negatable, -); // { dg-error "within this context" }
 105 STATIC_ASSERT((is_negatable<int>::value));
 106 STATIC_ASSERT((!is_negatable<int X::*>::value));
 107 STATIC_ASSERT((is_negatable<W>::value));
 108 STATIC_ASSERT((is_negatable<X>::value));
 109 STATIC_ASSERT((!is_negatable<Y>::value));
 110
 111 // is_dereferenceable
 112 DEFINE_PREFIX_UNARY_TRAIT(is_dereferenceable, *); // { dg-error "within this context" }
 113 STATIC_ASSERT((!is_dereferenceable<int>::value));
 114 STATIC_ASSERT((is_dereferenceable<int*>::value));
 115 STATIC_ASSERT((is_dereferenceable<W>::value));
 116 STATIC_ASSERT((is_dereferenceable<X>::value));
 117 STATIC_ASSERT((!is_dereferenceable<Y>::value));
 118
 119 // has_bitwise_not
 120 DEFINE_PREFIX_UNARY_TRAIT(has_bitwise_not, ~); // { dg-error "within this context" }
 121 STATIC_ASSERT((has_bitwise_not<int>::value));
 122 STATIC_ASSERT((!has_bitwise_not<int*>::value));
 123 STATIC_ASSERT((has_bitwise_not<W>::value));
 124 STATIC_ASSERT((has_bitwise_not<X>::value));
 125 STATIC_ASSERT((!has_bitwise_not<Y>::value));
 126
 127 // has_truth_not
 128 DEFINE_PREFIX_UNARY_TRAIT(has_truth_not, !); // { dg-error "within this context" }
 129 STATIC_ASSERT((has_truth_not<int>::value));
 130 STATIC_ASSERT((has_truth_not<int*>::value));
 131 STATIC_ASSERT((has_truth_not<W>::value));
 132 STATIC_ASSERT((has_truth_not<X>::value));
 133 STATIC_ASSERT((!has_truth_not<Y>::value));
 134
 135 // has_preincrement
 136 DEFINE_PREFIX_UNARY_TRAIT(has_preincrement, ++); // { dg-error "within this context" }
 137 STATIC_ASSERT((has_preincrement<int>::value));
 138 STATIC_ASSERT((has_preincrement<int*>::value));
 139 STATIC_ASSERT((!has_preincrement<int X::*>::value));
 140 STATIC_ASSERT((has_preincrement<W>::value));
 141 STATIC_ASSERT((has_preincrement<X>::value));
 142 STATIC_ASSERT((!has_preincrement<Y>::value));
 143
 144 // has_predecrement
 145 DEFINE_PREFIX_UNARY_TRAIT(has_predecrement, --); // { dg-error "within this context" }
 146 STATIC_ASSERT((has_predecrement<int>::value));
 147 STATIC_ASSERT((has_predecrement<int*>::value));
 148 STATIC_ASSERT((!has_predecrement<int X::*>::value));
 149 STATIC_ASSERT((has_predecrement<W>::value));
 150 STATIC_ASSERT((has_predecrement<X>::value));
 151 STATIC_ASSERT((!has_predecrement<Y>::value));
 152
 153 // has_postincrement
 154 DEFINE_POSTFIX_UNARY_TRAIT(has_postincrement, ++); // { dg-error "within this context" }
 155 STATIC_ASSERT((has_postincrement<int>::value));
 156 STATIC_ASSERT((has_postincrement<int*>::value));
 157 STATIC_ASSERT((!has_postincrement<int X::*>::value));
 158 STATIC_ASSERT((has_postincrement<W>::value));
 159 STATIC_ASSERT((has_postincrement<X>::value));
 160 STATIC_ASSERT((!has_postincrement<Y>::value));
 161
 162 // has_postdecrement
 163 DEFINE_POSTFIX_UNARY_TRAIT(has_postdecrement, --); // { dg-error "within this context" }
 164 STATIC_ASSERT((has_postdecrement<int>::value));
 165 STATIC_ASSERT((has_postdecrement<int*>::value));
 166 STATIC_ASSERT((!has_postdecrement<int X::*>::value));
 167 STATIC_ASSERT((has_postdecrement<W>::value));
 168 STATIC_ASSERT((has_postdecrement<X>::value));
 169 STATIC_ASSERT((!has_postdecrement<Y>::value));
 170
 171 // Check for private members
 172 STATIC_ASSERT((has_unary_plus<Z>::value)); // { dg-message "required from here" }
 173 STATIC_ASSERT((is_negatable<Z>::value)); // { dg-message "required from here" }
 174 STATIC_ASSERT((is_dereferenceable<Z>::value)); // { dg-message "required from here" }
 175 STATIC_ASSERT((has_bitwise_not<Z>::value)); // { dg-message "required from here" }
 176 STATIC_ASSERT((has_truth_not<Z>::value)); // { dg-message "required from here" }
 177 STATIC_ASSERT((has_preincrement<Z>::value)); // { dg-message "required from here" }
 178 STATIC_ASSERT((has_predecrement<Z>::value)); // { dg-message "required from here" }
 179 STATIC_ASSERT((has_postincrement<Z>::value)); // { dg-message "required from here" }
 180 STATIC_ASSERT((has_postdecrement<Z>::value)); // { dg-message "required from here" }
 181