clang/test/SemaCXX/nullptr.cpp

   1 // RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only -verify -std=c++11 -ffreestanding -Wno-null-conversion -Wno-tautological-compare %s
   2 #include <stdint.h>
   3
   4 typedef decltype(nullptr) nullptr_t;
   5
   6 struct A {};
   7
   8 int o1(char*);
   9 void o1(uintptr_t);
  10 void o2(char*); // expected-note {{candidate}}
  11 void o2(int A::*); // expected-note {{candidate}}
  12
  13 nullptr_t f(nullptr_t null)
  14 {
  15   // Implicit conversions.
  16   null = nullptr;
  17   void *p = nullptr;
  18   p = null;
  19   int *pi = nullptr;
  20   pi = null;
  21   null = 0;
  22   int A::*pm = nullptr;
  23   pm = null;
  24   void (*pf)() = nullptr;
  25   pf = null;
  26   void (A::*pmf)() = nullptr;
  27   pmf = null;
  28   bool b = nullptr; // expected-error {{cannot initialize}}
  29
  30   // Can't convert nullptr to integral implicitly.
  31   uintptr_t i = nullptr; // expected-error {{cannot initialize}}
  32
  33   // Operators
  34   (void)(null == nullptr);
  35   (void)(null <= nullptr); // expected-error {{invalid operands to binary expression}}
  36   (void)(null == 0);
  37   (void)(null == (void*)0);
  38   (void)((void*)0 == nullptr);
  39   (void)(null <= 0); // expected-error {{invalid operands to binary expression}}
  40   (void)(null <= (void*)0); // expected-error {{invalid operands to binary expression}}
  41   (void)((void*)0 <= nullptr); // expected-error {{invalid operands to binary expression}}
  42   (void)(0 == nullptr);
  43   (void)(nullptr == 0);
  44   (void)(nullptr <= 0); // expected-error {{invalid operands to binary expression}}
  45   (void)(0 <= nullptr); // expected-error {{invalid operands to binary expression}}
  46   (void)(1 > nullptr); // expected-error {{invalid operands to binary expression}}
  47   (void)(1 != nullptr); // expected-error {{invalid operands to binary expression}}
  48   (void)(1 + nullptr); // expected-error {{invalid operands to binary expression}}
  49   (void)(0 ? nullptr : 0);
  50   (void)(0 ? nullptr : (void*)0);
  51   (void)(0 ? nullptr : A()); // expected-error {{non-pointer operand type 'A' incompatible with nullptr}}
  52   (void)(0 ? A() : nullptr); // expected-error {{non-pointer operand type 'A' incompatible with nullptr}}
  53
  54   // Overloading
  55   int t = o1(nullptr);
  56   t = o1(null);
  57   o2(nullptr); // expected-error {{ambiguous}}
  58
  59   // nullptr is an rvalue, null is an lvalue
  60   (void)&nullptr; // expected-error {{cannot take the address of an rvalue of type 'std::nullptr_t'}}
  61   nullptr_t *pn = &null;
  62
  63   // You can reinterpret_cast nullptr to an integer.
  64   (void)reinterpret_cast<uintptr_t>(nullptr);
  65   (void)reinterpret_cast<uintptr_t>(*pn);
  66
  67   // You can't reinterpret_cast nullptr to any integer
  68   (void)reinterpret_cast<char>(nullptr); // expected-error {{cast from pointer to smaller type 'char' loses information}}
  69
  70   int *ip = *pn;
  71   if (*pn) { }
  72
  73   // You can throw nullptr.
  74   throw nullptr;
  75 }
  76
  77 // Template arguments can be nullptr.
  78 template <int *PI, void (*PF)(), int A::*PM, void (A::*PMF)()>
  79 struct T {};
  80
  81 typedef T<nullptr, nullptr, nullptr, nullptr> NT;
  82
  83 namespace test1 {
  84 template<typename T, typename U> struct is_same {
  85   static const bool value = false;
  86 };
  87
  88 template<typename T> struct is_same<T, T> {
  89   static const bool value = true;
  90 };
  91
  92 void *g(void*);
  93 bool g(bool);
  94
  95 // Test that we prefer g(void*) over g(bool).
  96 static_assert(is_same<decltype(g(nullptr)), void*>::value, "");
  97 }
  98
  99 namespace test2 {
 100   void f(int, ...) __attribute__((sentinel));
 101
 102   void g() {
 103     // nullptr can be used as the sentinel value.
 104     f(10, nullptr);
 105   }
 106 }
 107
 108 namespace test3 {
 109   void f(const char*, ...) __attribute__((format(printf, 1, 2)));
 110
 111   void g() {
 112     // Don't warn when using nullptr with %p.
 113     f("%p", nullptr);
 114   }
 115 }
 116
 117 static_assert(__is_scalar(nullptr_t), "");
 118 static_assert(__is_pod(nullptr_t), "");
 119 static_assert(sizeof(nullptr_t) == sizeof(void*), "");
 120
 121 static_assert(!(nullptr < nullptr), ""); // expected-error {{invalid operands to binary expression}}
 122 static_assert(!(nullptr > nullptr), ""); // expected-error {{invalid operands to binary expression}}
 123 static_assert(  nullptr <= nullptr, ""); // expected-error {{invalid operands to binary expression}}
 124 static_assert(  nullptr >= nullptr, ""); // expected-error {{invalid operands to binary expression}}
 125 static_assert(  nullptr == nullptr, "");
 126 static_assert(!(nullptr != nullptr), "");
 127
 128 static_assert(!(0 < nullptr), ""); // expected-error {{invalid operands to binary expression}}
 129 static_assert(!(0 > nullptr), ""); // expected-error {{invalid operands to binary expression}}
 130 static_assert(  0 <= nullptr, ""); // expected-error {{invalid operands to binary expression}}
 131 static_assert(  0 >= nullptr, ""); // expected-error {{invalid operands to binary expression}}
 132 static_assert(  0 == nullptr, "");
 133 static_assert(!(0 != nullptr), "");
 134
 135 static_assert(!(nullptr < 0), ""); // expected-error {{invalid operands to binary expression}}
 136 static_assert(!(nullptr > 0), ""); // expected-error {{invalid operands to binary expression}}
 137 static_assert(  nullptr <= 0, ""); // expected-error {{invalid operands to binary expression}}
 138 static_assert(  nullptr >= 0, ""); // expected-error {{invalid operands to binary expression}}
 139 static_assert(  nullptr == 0, "");
 140 static_assert(!(nullptr != 0), "");
 141
 142 namespace overloading {
 143   int &f1(int*);
 144   float &f1(bool);
 145
 146   void test_f1() {
 147     int &ir = (f1)(nullptr);
 148   }
 149
 150   struct ConvertsToNullPtr {
 151     operator nullptr_t() const;
 152   };
 153
 154   void test_conversion(ConvertsToNullPtr ctn) {
 155     (void)(ctn == ctn);
 156     (void)(ctn != ctn);
 157     (void)(ctn <= ctn); // expected-error {{invalid operands to binary expression}}
 158     (void)(ctn >= ctn); // expected-error {{invalid operands to binary expression}}
 159     (void)(ctn < ctn); // expected-error {{invalid operands to binary expression}}
 160     (void)(ctn > ctn); // expected-error {{invalid operands to binary expression}}
 161   }
 162 }
 163
 164 namespace templates {
 165   template<typename T, nullptr_t Value>
 166   struct X {
 167     X() { ptr = Value; }
 168
 169     T *ptr;
 170   };
 171
 172   X<int, nullptr> x;
 173
 174
 175   template<int (*fp)(int), int* p, int A::* pmd, int (A::*pmf)(int)>
 176   struct X2 {};
 177
 178   X2<nullptr, nullptr, nullptr, nullptr> x2;
 179 }
 180
 181 namespace null_pointer_constant {
 182
 183 // Pending implementation of core issue 903, ensure we don't allow any of the
 184 // C++11 constant evaluation semantics in null pointer constants.
 185 struct S { int n; };
 186 constexpr int null() { return 0; }
 187 void *p = S().n; // expected-error {{cannot initialize}}
 188 void *q = null(); // expected-error {{cannot initialize}}
 189
 190 }