const-cast.cpp revision ffd408a50adb01ae9c0ad92fb5f0981e1ca72df5 
1// RUN: clang-cc -fsyntax-only -verify %s
2
3struct A {};
4
5// See if aliasing can confuse this baby.
6typedef char c;
7typedef c *cp;
8typedef cp *cpp;
9typedef cpp *cppp;
10typedef cppp &cpppr;
11typedef const cppp &cpppcr;
12typedef const char cc;
13typedef cc *ccp;
14typedef volatile ccp ccvp;
15typedef ccvp *ccvpp;
16typedef const volatile ccvpp ccvpcvp;
17typedef ccvpcvp *ccvpcvpp;
18typedef int iar[100];
19typedef iar &iarr;
20typedef int (*f)(int);
21
22char ***good_const_cast_test(ccvpcvpp var)
23{
24  // Cast away deep consts and volatiles.
25  char ***var2 = const_cast<cppp>(var);
26  char ***const &var3 = var2;
27  // Const reference to reference.
28  char ***&var4 = const_cast<cpppr>(var3);
29  // Drop reference. Intentionally without qualifier change.
30  char *** var5 = const_cast<cppp>(var4);
31  const int ar[100] = {0};
32  int (&rar)[100] = const_cast<iarr>(ar); // expected-error {{const_cast from 'int const [100]' to 'iarr' (aka 'iar &') is not allowed}}
33  // Array decay. Intentionally without qualifier change.
34  int *pi = const_cast<int*>(ar);
35  f fp = 0;
36  // Don't misidentify fn** as a function pointer.
37  f *fpp = const_cast<f*>(&fp);
38  int const A::* const A::*icapcap = 0;
39  int A::* A::* iapap = const_cast<int A::* A::*>(icapcap);
40
41  return var4;
42}
43
44short *bad_const_cast_test(char const *volatile *const volatile *var)
45{
46  // Different pointer levels.
47  char **var2 = const_cast<char**>(var); // expected-error {{const_cast from 'char const *volatile *const volatile *' to 'char **' is not allowed}}
48  // Different final type.
49  short ***var3 = const_cast<short***>(var); // expected-error {{const_cast from 'char const *volatile *const volatile *' to 'short ***' is not allowed}}
50  // Rvalue to reference.
51  char ***&var4 = const_cast<cpppr>(&var2); // expected-error {{const_cast from rvalue to reference type 'cpppr'}}
52  // Non-pointer.
53  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}}
54  const int *ar[100] = {0};
55  // Not even lenient g++ accepts this.
56  int *(*rar)[100] = const_cast<int *(*)[100]>(&ar); // expected-error {{const_cast from 'int const *(*)[100]' to 'int *(*)[100]' is not allowed}}
57  f fp1 = 0;
58  // Function pointers.
59  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}}
60  void (A::*mfn)() = 0;
61  (void)const_cast<void (A::*)()>(mfn); // expected-error {{const_cast to 'void (struct A::*)(void)', which is not a reference, pointer-to-object, or pointer-to-data-member}}
62  return **var3;
63}
64