test/SemaCXX/static-cast.cpp

   1 // RUN: clang-cc -fsyntax-only -verify %s
   2
   3 struct A {};
   4 struct B : public A {};             // Single public base.
   5 struct C1 : public virtual B {};    // Single virtual base.
   6 struct C2 : public virtual B {};
   7 struct D : public C1, public C2 {}; // Diamond
   8 struct E : private A {};            // Single private base.
   9 struct F : public C1 {};            // Single path to B with virtual.
  10 struct G1 : public B {};
  11 struct G2 : public B {};
  12 struct H : public G1, public G2 {}; // Ambiguous path to B.
  13
  14 enum Enum { En1, En2 };
  15 enum Onom { On1, On2 };
  16
  17 // Explicit implicits
  18 void t_529_2()
  19 {
  20   int i = 1;
  21   (void)static_cast<float>(i);
  22   double d = 1.0;
  23   (void)static_cast<float>(d);
  24   (void)static_cast<int>(d);
  25   (void)static_cast<char>(i);
  26   (void)static_cast<unsigned long>(i);
  27   (void)static_cast<int>(En1);
  28   (void)static_cast<double>(En1);
  29   (void)static_cast<int&>(i);
  30   (void)static_cast<const int&>(i);
  31
  32   int ar[1];
  33   (void)static_cast<const int*>(ar);
  34   (void)static_cast<void (*)()>(t_529_2);
  35
  36   (void)static_cast<void*>(0);
  37   (void)static_cast<void*>((int*)0);
  38   (void)static_cast<volatile const void*>((const int*)0);
  39   (void)static_cast<A*>((B*)0);
  40   (void)static_cast<A&>(*((B*)0));
  41   (void)static_cast<const B*>((C1*)0);
  42   (void)static_cast<B&>(*((C1*)0));
  43   (void)static_cast<A*>((D*)0);
  44   (void)static_cast<const A&>(*((D*)0));
  45   (void)static_cast<int B::*>((int A::*)0);
  46   (void)static_cast<void (B::*)()>((void (A::*)())0);
  47
  48   // TODO: User-defined conversions
  49
  50   // Bad code below
  51
  52   (void)static_cast<void*>((const int*)0); // expected-error {{static_cast from 'int const *' to 'void *' is not allowed}}
  53   //(void)static_cast<A*>((E*)0); // {{static_cast from 'struct E *' to 'struct A *' is not allowed}}
  54   //(void)static_cast<A*>((H*)0); // {{static_cast from 'struct H *' to 'struct A *' is not allowed}}
  55   (void)static_cast<int>((int*)0); // expected-error {{static_cast from 'int *' to 'int' is not allowed}}
  56   (void)static_cast<A**>((B**)0); // expected-error {{static_cast from 'struct B **' to 'struct A **' is not allowed}}
  57   (void)static_cast<char&>(i); // expected-error {{non-const lvalue reference to type 'char' cannot be initialized with a value of type 'int'}}
  58 }
  59
  60 // Anything to void
  61 void t_529_4()
  62 {
  63   static_cast<void>(1);
  64   static_cast<void>(t_529_4);
  65 }
  66
  67 // Static downcasts
  68 void t_529_5_8()
  69 {
  70   (void)static_cast<B*>((A*)0);
  71   (void)static_cast<B&>(*((A*)0));
  72   (void)static_cast<const G1*>((A*)0);
  73   (void)static_cast<const G1&>(*((A*)0));
  74
  75   // Bad code below
  76
  77   (void)static_cast<C1*>((A*)0); // expected-error {{cannot cast 'struct A *' to 'struct C1 *' via virtual base 'struct B'}}
  78   (void)static_cast<C1&>(*((A*)0)); // expected-error {{cannot cast 'struct A' to 'struct C1 &' via virtual base 'struct B'}}
  79   (void)static_cast<D*>((A*)0); // expected-error {{cannot cast 'struct A *' to 'struct D *' via virtual base 'struct B'}}
  80   (void)static_cast<D&>(*((A*)0)); // expected-error {{cannot cast 'struct A' to 'struct D &' via virtual base 'struct B'}}
  81   (void)static_cast<B*>((const A*)0); // expected-error {{static_cast from 'struct A const *' to 'struct B *' casts away constness}}
  82   (void)static_cast<B&>(*((const A*)0)); // expected-error {{static_cast from 'struct A const' to 'struct B &' casts away constness}}
  83   // Accessibility is not yet tested
  84   //(void)static_cast<E*>((A*)0); // {{static_cast from 'struct A *' to 'struct E *' is not allowed}}
  85   //(void)static_cast<E&>(*((A*)0)); // {{static_cast from 'struct A' to 'struct E &' is not allowed}}
  86   (void)static_cast<H*>((A*)0); // expected-error {{ambiguous static_cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
  87   (void)static_cast<H&>(*((A*)0)); // expected-error {{ambiguous static_cast from base 'struct A' to derived 'struct H':\n    struct A -> struct B -> struct G1 -> struct H\n    struct A -> struct B -> struct G2 -> struct H}}
  88   (void)static_cast<E*>((B*)0); // expected-error {{static_cast from 'struct B *' to 'struct E *' is not allowed}}
  89   (void)static_cast<E&>(*((B*)0)); // expected-error {{non-const lvalue reference to type 'struct E' cannot be initialized with a value of type 'struct B'}}
  90
  91   // TODO: Test inaccessible base in context where it's accessible, i.e.
  92   // member function and friend.
  93
  94   // TODO: Test DR427. This requires user-defined conversions, though.
  95 }
  96
  97 // Enum conversions
  98 void t_529_7()
  99 {
 100   (void)static_cast<Enum>(1);
 101   (void)static_cast<Enum>(1.0);
 102   (void)static_cast<Onom>(En1);
 103
 104   // Bad code below
 105
 106   (void)static_cast<Enum>((int*)0); // expected-error {{static_cast from 'int *' to 'enum Enum' is not allowed}}
 107 }
 108
 109 // Void pointer to object pointer
 110 void t_529_10()
 111 {
 112   (void)static_cast<int*>((void*)0);
 113   (void)static_cast<const A*>((void*)0);
 114
 115   // Bad code below
 116
 117   (void)static_cast<int*>((const void*)0); // expected-error {{static_cast from 'void const *' to 'int *' casts away constness}}
 118   (void)static_cast<void (*)()>((void*)0); // expected-error {{static_cast from 'void *' to 'void (*)()' is not allowed}}
 119 }
 120
 121 // Member pointer upcast.
 122 void t_529_9()
 123 {
 124   (void)static_cast<int A::*>((int B::*)0);
 125
 126   // Bad code below
 127   (void)static_cast<int A::*>((int H::*)0); // expected-error {{ambiguous conversion from pointer to member of derived class 'struct H'}}
 128   (void)static_cast<int A::*>((int F::*)0); // expected-error {{conversion from pointer to member of class 'struct F'}}
 129 }