clang/test/CXX/expr/expr.const/p5-26.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -std=c++2c -verify=expected,cxx26 %s
   2 // RUN: %clang_cc1 -fsyntax-only -std=c++2b -verify=expected,cxx23 %s
   3
   4
   5 struct S {};
   6 struct T : S {} t;
   7
   8 consteval void test() {
   9     void* a = &t;
  10     const void* b = &t;
  11     volatile void* c = &t;
  12     (void)static_cast<T*>(a);
  13     (void)static_cast<const T*>(a);
  14     (void)static_cast<volatile T*>(a);
  15
  16     (void)(T*)(a);
  17     (void)(const T*)(a);
  18     (void)(volatile T*)(a);
  19
  20     (void)static_cast<T*>(b); // expected-error {{static_cast from 'const void *' to 'T *' casts away qualifiers}}
  21     (void)static_cast<volatile T*>(b); // expected-error {{static_cast from 'const void *' to 'volatile T *' casts away qualifiers}}
  22     (void)static_cast<const T*>(b);
  23     (void)static_cast<volatile const T*>(b);
  24
  25     (void)static_cast<T*>(c); // expected-error{{static_cast from 'volatile void *' to 'T *' casts away qualifiers}}
  26     (void)static_cast<volatile T*>(c);
  27     (void)static_cast<const T*>(b);
  28     (void)static_cast<volatile const T*>(b);
  29 }
  30
  31 void err() {
  32     constexpr void* a = &t;
  33     constexpr auto err1 = static_cast<int*>(a); // expected-error{{constexpr variable 'err1' must be initialized by a constant expression}} \
  34                                                 // cxx23-note {{cast from 'void *' is not allowed in a constant expression in C++ standards before C++2c}} \
  35                                                 // cxx26-note {{cast from 'void *' is not allowed in a constant expression because the pointed object type 'T' is not similar to the target type 'int'}}
  36     constexpr auto err2 = static_cast<S*>(a);   // expected-error{{constexpr variable 'err2' must be initialized by a constant expression}} \
  37                                                 // cxx23-note {{cast from 'void *' is not allowed in a constant expression in C++ standards before C++2c}} \
  38                                                 // cxx26-note {{cast from 'void *' is not allowed in a constant expression because the pointed object type 'T' is not similar to the target type 'S'}}
  39 }
  40
  41 int* p;
  42 constexpr int** pp = &p;
  43 constexpr void* vp = pp;
  44 constexpr auto cvp = static_cast<const int* volatile*>(vp);
  45 // cxx23-error@-1 {{constant expression}}
  46 // cxx23-note@-2 {{cast from 'void *' is not allowed in a constant expression}}