xref: /aosp_15_r20/external/clang/test/SemaCXX/const-cast.cpp (revision 67e74705e28f6214e480b399dd47ea732279e315)
1*67e74705SXin Li // RUN: %clang_cc1 -fsyntax-only -verify %s
2*67e74705SXin Li // RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s
3*67e74705SXin Li // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
4*67e74705SXin Li 
5*67e74705SXin Li struct A {};
6*67e74705SXin Li 
7*67e74705SXin Li // See if aliasing can confuse this baby.
8*67e74705SXin Li typedef char c;
9*67e74705SXin Li typedef c *cp;
10*67e74705SXin Li typedef cp *cpp;
11*67e74705SXin Li typedef cpp *cppp;
12*67e74705SXin Li typedef cppp &cpppr;
13*67e74705SXin Li typedef const cppp &cpppcr;
14*67e74705SXin Li typedef const char cc;
15*67e74705SXin Li typedef cc *ccp;
16*67e74705SXin Li typedef volatile ccp ccvp;
17*67e74705SXin Li typedef ccvp *ccvpp;
18*67e74705SXin Li typedef const volatile ccvpp ccvpcvp;
19*67e74705SXin Li typedef ccvpcvp *ccvpcvpp;
20*67e74705SXin Li typedef int iar[100];
21*67e74705SXin Li typedef iar &iarr;
22*67e74705SXin Li typedef int (*f)(int);
23*67e74705SXin Li 
good_const_cast_test(ccvpcvpp var)24*67e74705SXin Li char ***good_const_cast_test(ccvpcvpp var)
25*67e74705SXin Li {
26*67e74705SXin Li   // Cast away deep consts and volatiles.
27*67e74705SXin Li   char ***var2 = const_cast<cppp>(var);
28*67e74705SXin Li   char ***const &var3 = var2;
29*67e74705SXin Li   // Const reference to reference.
30*67e74705SXin Li   char ***&var4 = const_cast<cpppr>(var3);
31*67e74705SXin Li   // Drop reference. Intentionally without qualifier change.
32*67e74705SXin Li   char *** var5 = const_cast<cppp>(var4);
33*67e74705SXin Li   // Const array to array reference.
34*67e74705SXin Li   const int ar[100] = {0};
35*67e74705SXin Li   int (&rar)[100] = const_cast<iarr>(ar);
36*67e74705SXin Li   // Array decay. Intentionally without qualifier change.
37*67e74705SXin Li   int *pi = const_cast<int*>(ar);
38*67e74705SXin Li   f fp = 0;
39*67e74705SXin Li   // Don't misidentify fn** as a function pointer.
40*67e74705SXin Li   f *fpp = const_cast<f*>(&fp);
41*67e74705SXin Li   int const A::* const A::*icapcap = 0;
42*67e74705SXin Li   int A::* A::* iapap = const_cast<int A::* A::*>(icapcap);
43*67e74705SXin Li   (void)const_cast<A&&>(A());
44*67e74705SXin Li #if __cplusplus <= 199711L // C++03 or earlier modes
45*67e74705SXin Li   // expected-warning@-2 {{rvalue references are a C++11 extension}}
46*67e74705SXin Li #endif
47*67e74705SXin Li   return var4;
48*67e74705SXin Li }
49*67e74705SXin Li 
bad_const_cast_test(char const * volatile * const volatile * var)50*67e74705SXin Li short *bad_const_cast_test(char const *volatile *const volatile *var)
51*67e74705SXin Li {
52*67e74705SXin Li   // Different pointer levels.
53*67e74705SXin Li   char **var2 = const_cast<char**>(var); // expected-error {{const_cast from 'const char *volatile *const volatile *' to 'char **' is not allowed}}
54*67e74705SXin Li   // Different final type.
55*67e74705SXin Li   short ***var3 = const_cast<short***>(var); // expected-error {{const_cast from 'const char *volatile *const volatile *' to 'short ***' is not allowed}}
56*67e74705SXin Li   // Rvalue to reference.
57*67e74705SXin Li   char ***&var4 = const_cast<cpppr>(&var2); // expected-error {{const_cast from rvalue to reference type 'cpppr'}}
58*67e74705SXin Li   // Non-pointer.
59*67e74705SXin Li   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}}
60*67e74705SXin Li   const int *ar[100] = {0};
61*67e74705SXin Li   // Not even lenient g++ accepts this.
62*67e74705SXin Li   int *(*rar)[100] = const_cast<int *(*)[100]>(&ar); // expected-error {{const_cast from 'const int *(*)[100]' to 'int *(*)[100]' is not allowed}}
63*67e74705SXin Li   f fp1 = 0;
64*67e74705SXin Li   // Function pointers.
65*67e74705SXin Li   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}}
66*67e74705SXin Li   void (A::*mfn)() = 0;
67*67e74705SXin Li   (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}}
68*67e74705SXin Li   (void)const_cast<int&&>(0); // expected-error {{const_cast from rvalue to reference type 'int &&'}}
69*67e74705SXin Li #if __cplusplus <= 199711L // C++03 or earlier modes
70*67e74705SXin Li   // expected-warning@-2 {{rvalue references are a C++11 extension}}
71*67e74705SXin Li #endif
72*67e74705SXin Li   return **var3;
73*67e74705SXin Li }
74*67e74705SXin Li 
75*67e74705SXin Li template <typename T>
PR21845()76*67e74705SXin Li char *PR21845() { return const_cast<char *>((void)T::x); } // expected-error {{const_cast from 'void' to 'char *' is not allowed}}
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