const-cast.cpp
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// RUN: %clang_cc1 -fsyntax-only -verify %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
struct A {};
// See if aliasing can confuse this baby.
typedef char c;
typedef c *cp;
typedef cp *cpp;
typedef cpp *cppp;
typedef cppp &cpppr;
typedef const cppp &cpppcr;
typedef const char cc;
typedef cc *ccp;
typedef volatile ccp ccvp;
typedef ccvp *ccvpp;
typedef const volatile ccvpp ccvpcvp;
typedef ccvpcvp *ccvpcvpp;
typedef int iar[100];
typedef iar &iarr;
typedef int (*f)(int);
char ***good_const_cast_test(ccvpcvpp var)
{
// Cast away deep consts and volatiles.
char ***var2 = const_cast<cppp>(var);
char ***const &var3 = var2;
// Const reference to reference.
char ***&var4 = const_cast<cpppr>(var3);
// Drop reference. Intentionally without qualifier change.
char *** var5 = const_cast<cppp>(var4);
// Const array to array reference.
const int ar[100] = {0};
int (&rar)[100] = const_cast<iarr>(ar);
// Array decay. Intentionally without qualifier change.
int *pi = const_cast<int*>(ar);
f fp = 0;
// Don't misidentify fn** as a function pointer.
f *fpp = const_cast<f*>(&fp);
int const A::* const A::*icapcap = 0;
int A::* A::* iapap = const_cast<int A::* A::*>(icapcap);
(void)const_cast<A&&>(A());
#if __cplusplus <= 199711L // C++03 or earlier modes
// expected-warning@-2 {{rvalue references are a C++11 extension}}
#endif
return var4;
}
short *bad_const_cast_test(char const *volatile *const volatile *var)
{
// Different pointer levels.
char **var2 = const_cast<char**>(var); // expected-error {{const_cast from 'const char *volatile *const volatile *' to 'char **' is not allowed}}
// Different final type.
short ***var3 = const_cast<short***>(var); // expected-error {{const_cast from 'const char *volatile *const volatile *' to 'short ***' is not allowed}}
// Rvalue to reference.
char ***&var4 = const_cast<cpppr>(&var2); // expected-error {{const_cast from rvalue to reference type 'cpppr'}}
// Non-pointer.
char v = const_cast<char>(**var2); // expected-error {{const_cast to 'char', which is not a reference, pointer-to-object, or pointer-to-data-member}}
const int *ar[100] = {0};
extern const int *aub[];
// const_cast looks through arrays as of DR330.
(void) const_cast<int *(*)[100]>(&ar); // ok
(void) const_cast<int *(*)[]>(&aub); // ok
// ... but the array bound must exactly match.
(void) const_cast<int *(*)[]>(&ar); // expected-error {{const_cast from 'const int *(*)[100]' to 'int *(*)[]' is not allowed}}
(void) const_cast<int *(*)[99]>(&ar); // expected-error {{const_cast from 'const int *(*)[100]' to 'int *(*)[99]' is not allowed}}
(void) const_cast<int *(*)[100]>(&aub); // expected-error {{const_cast from 'const int *(*)[]' to 'int *(*)[100]' is not allowed}}
f fp1 = 0;
// Function pointers.
f fp2 = const_cast<f>(fp1); // expected-error {{const_cast to 'f' (aka 'int (*)(int)'), which is not a reference, pointer-to-object, or pointer-to-data-member}}
void (A::*mfn)() = 0;
(void)const_cast<void (A::*)()>(mfn); // expected-error-re {{const_cast to 'void (A::*)(){{( __attribute__\(\(thiscall\)\))?}}', which is not a reference, pointer-to-object, or pointer-to-data-member}}
(void)const_cast<int&&>(0); // expected-error {{const_cast from rvalue to reference type 'int &&'}}
#if __cplusplus <= 199711L // C++03 or earlier modes
// expected-warning@-2 {{rvalue references are a C++11 extension}}
#endif
return **var3;
}
template <typename T>
char *PR21845() { return const_cast<char *>((void)T::x); } // expected-error {{const_cast from 'void' to 'char *' is not allowed}}