clang/test/SemaCXX/cstyle-cast.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s
   2 // REQUIRES: LP64
   3
   4 struct A {};
   5
   6 // ----------- const_cast --------------
   7
   8 typedef char c;
   9 typedef c *cp;
  10 typedef cp *cpp;
  11 typedef cpp *cppp;
  12 typedef cppp &cpppr;
  13 typedef const cppp &cpppcr;
  14 typedef const char cc;
  15 typedef cc *ccp;
  16 typedef volatile ccp ccvp;
  17 typedef ccvp *ccvpp;
  18 typedef const volatile ccvpp ccvpcvp;
  19 typedef ccvpcvp *ccvpcvpp;
  20 typedef int iar[100];
  21 typedef iar &iarr;
  22 typedef int (*f)(int);
  23
  24 void t_cc()
  25 {
  26   ccvpcvpp var = 0;
  27   // Cast away deep consts and volatiles.
  28   char ***var2 = (cppp)(var);
  29   char ***const &var3 = var2;
  30   // Const reference to reference.
  31   char ***&var4 = (cpppr)(var3);
  32   // Drop reference. Intentionally without qualifier change.
  33   char *** var5 = (cppp)(var4);
  34   const int ar[100] = {0};
  35   // Array decay. Intentionally without qualifier change.
  36   int *pi = (int*)(ar);
  37   f fp = 0;
  38   // Don't misidentify fn** as a function pointer.
  39   f *fpp = (f*)(&fp);
  40   int const A::* const A::*icapcap = 0;
  41   int A::* A::* iapap = (int A::* A::*)(icapcap);
  42 }
  43
  44 // ----------- static_cast -------------
  45
  46 struct B : public A {};             // Single public base.
  47 struct C1 : public virtual B {};    // Single virtual base.
  48 struct C2 : public virtual B {};
  49 struct D : public C1, public C2 {}; // Diamond
  50 struct E : private A {};            // Single private base.
  51 struct F : public C1 {};            // Single path to B with virtual.
  52 struct G1 : public B {};
  53 struct G2 : public B {};
  54 struct H : public G1, public G2 {}; // Ambiguous path to B.
  55
  56 enum Enum { En1, En2 };
  57 enum Onom { On1, On2 };
  58
  59 struct Co1 { operator int(); };
  60 struct Co2 { Co2(int); };
  61 struct Co3 { };
  62 struct Co4 { Co4(Co3); operator Co3(); };
  63
  64 // Explicit implicits
  65 void t_529_2()
  66 {
  67   int i = 1;
  68   (void)(float)(i);
  69   double d = 1.0;
  70   (void)(float)(d);
  71   (void)(int)(d);
  72   (void)(char)(i);
  73   (void)(unsigned long)(i);
  74   (void)(int)(En1);
  75   (void)(double)(En1);
  76   (void)(int&)(i);
  77   (void)(const int&)(i);
  78
  79   int ar[1];
  80   (void)(const int*)(ar);
  81   (void)(void (*)())(t_529_2);
  82
  83   (void)(void*)(0);
  84   (void)(void*)((int*)0);
  85   (void)(volatile const void*)((const int*)0);
  86   (void)(A*)((B*)0);
  87   (void)(A&)(*((B*)0)); // expected-warning {{binding dereferenced null pointer to reference has undefined behavior}}
  88   (void)(const B*)((C1*)0);
  89   (void)(B&)(*((C1*)0)); // expected-warning {{binding dereferenced null pointer to reference has undefined behavior}}
  90   (void)(A*)((D*)0);
  91   (void)(const A&)(*((D*)0)); // expected-warning {{binding dereferenced null pointer to reference has undefined behavior}}
  92   (void)(int B::*)((int A::*)0);
  93   (void)(void (B::*)())((void (A::*)())0);
  94   (void)(A*)((E*)0); // C-style cast ignores access control
  95   (void)(void*)((const int*)0); // const_cast appended
  96
  97   (void)(int)(Co1());
  98   (void)(Co2)(1);
  99   (void)(Co3)((Co4)(Co3()));
 100
 101   // Bad code below
 102   //(void)(A*)((H*)0); // {{static_cast from 'struct H *' to 'struct A *' is not allowed}}
 103 }
 104
 105 // Anything to void
 106 void t_529_4()
 107 {
 108   (void)(1);
 109   (void)(t_529_4);
 110 }
 111
 112 // Static downcasts
 113 void t_529_5_8()
 114 {
 115   (void)(B*)((A*)0);
 116   (void)(B&)(*((A*)0));
 117   (void)(const G1*)((A*)0);
 118   (void)(const G1&)(*((A*)0));
 119   (void)(B*)((const A*)0); // const_cast appended
 120   (void)(B&)(*((const A*)0)); // const_cast appended
 121   (void)(E*)((A*)0); // access control ignored
 122   (void)(E&)(*((A*)0)); // access control ignored
 123
 124   // Bad code below
 125
 126   (void)(C1*)((A*)0); // expected-error {{cannot cast 'A *' to 'C1 *' via virtual base 'B'}}
 127   (void)(C1&)(*((A*)0)); // expected-error {{cannot cast 'A' to 'C1 &' via virtual base 'B'}}
 128   (void)(D*)((A*)0); // expected-error {{cannot cast 'A *' to 'D *' via virtual base 'B'}}
 129   (void)(D&)(*((A*)0)); // expected-error {{cannot cast 'A' to 'D &' via virtual base 'B'}}
 130   (void)(H*)((A*)0); // expected-error {{ambiguous cast from base 'A' to derived 'H':\n    A -> B -> G1 -> struct H\n    A -> B -> G2 -> struct H}}
 131   (void)(H&)(*((A*)0)); // expected-error {{ambiguous cast from base 'A' to derived 'H':\n    A -> B -> G1 -> struct H\n    A -> B -> G2 -> struct H}}
 132
 133   // TODO: Test DR427. This requires user-defined conversions, though.
 134 }
 135
 136 // Enum conversions
 137 void t_529_7()
 138 {
 139   (void)(Enum)(1);
 140   (void)(Enum)(1.0);
 141   (void)(Onom)(En1);
 142
 143   // Bad code below
 144
 145   (void)(Enum)((int*)0); // expected-error {{C-style cast from 'int *' to 'Enum' is not allowed}}
 146 }
 147
 148 // Void pointer to object pointer
 149 void t_529_10()
 150 {
 151   (void)(int*)((void*)0);
 152   (void)(const A*)((void*)0);
 153   (void)(int*)((const void*)0); // const_cast appended
 154 }
 155
 156 // Member pointer upcast.
 157 void t_529_9()
 158 {
 159   (void)(int A::*)((int B::*)0);
 160
 161   // Bad code below
 162   (void)(int A::*)((int H::*)0); // expected-error {{ambiguous conversion from pointer to member of derived class 'H' to pointer to member of base class 'A':}}
 163   (void)(int A::*)((int F::*)0); // expected-error {{conversion from pointer to member of class 'F' to pointer to member of class 'A' via virtual base 'B' is not allowed}}
 164 }
 165
 166 // -------- reinterpret_cast -----------
 167
 168 enum test { testval = 1 };
 169 struct structure { int m; };
 170 typedef void (*fnptr)();
 171
 172 // Test conversion between pointer and integral types, as in p3 and p4.
 173 void integral_conversion()
 174 {
 175   void *vp = (void*)(testval);
 176   long l = (long)(vp);
 177   (void)(float*)(l);
 178   fnptr fnp = (fnptr)(l);
 179   (void)(char)(fnp); // expected-error {{cast from pointer to smaller type 'char' loses information}}
 180   (void)(long)(fnp);
 181
 182   (void)(bool)((void*)0);
 183   (void)(bool)((int*)0);
 184   (void)(char)((void*)0); // expected-error {{cast from pointer to smaller type 'char' loses information}}
 185   (void)(char)((int*)0);  // expected-error {{cast from pointer to smaller type 'char' loses information}}
 186 }
 187
 188 void pointer_conversion()
 189 {
 190   int *p1 = 0;
 191   float *p2 = (float*)(p1);
 192   structure *p3 = (structure*)(p2);
 193   typedef int **ppint;
 194   ppint *deep = (ppint*)(p3);
 195   (void)(fnptr*)(deep);
 196 }
 197
 198 void constness()
 199 {
 200   int ***const ipppc = 0;
 201   int const *icp = (int const*)(ipppc);
 202   (void)(int*)(icp); // const_cast appended
 203   int const *const **icpcpp = (int const* const**)(ipppc); // const_cast appended
 204   int *ip = (int*)(icpcpp);
 205   (void)(int const*)(ip);
 206   (void)(int const* const* const*)(ipppc);
 207 }
 208
 209 void fnptrs()
 210 {
 211   typedef int (*fnptr2)(int);
 212   fnptr fp = 0;
 213   (void)(fnptr2)(fp);
 214   void *vp = (void*)(fp);
 215   (void)(fnptr)(vp);
 216 }
 217
 218 void refs()
 219 {
 220   long l = 0;
 221   char &c = (char&)(l);
 222   // Bad: from rvalue
 223   (void)(int&)(&c); // expected-error {{C-style cast from rvalue to reference type 'int &'}}
 224 }
 225
 226 void memptrs()
 227 {
 228   const int structure::*psi = 0;
 229   (void)(const float structure::*)(psi);
 230   (void)(int structure::*)(psi); // const_cast appended
 231
 232   void (structure::*psf)() = 0;
 233   (void)(int (structure::*)())(psf);
 234
 235   (void)(void (structure::*)())(psi); // expected-error-re {{C-style cast from 'const int structure::*' to 'void (structure::*)(){{( __attribute__\(\(thiscall\)\))?}}' is not allowed}}
 236   (void)(int structure::*)(psf); // expected-error-re {{C-style cast from 'void (structure::*)(){{( __attribute__\(\(thiscall\)\))?}}' to 'int structure::*' is not allowed}}
 237 }