1 // RUN: %clang_cc1 -std=c2x -Wall -pedantic -verify %s
2 // RUN: %clang_cc1 -std=c17 -Wall -pedantic -verify %s
3
4 /* WG14 N2607: Partial
5 * Compatibility of Pointers to Arrays with Qualifiers
6 *
7 * FIXME: We consider this partially implemented because there are still issues
8 * with the composite type from a conditional operator. Further, we don't issue
9 * any diagnostics in C17 or earlier when we need at least a pedantic
10 * diagnostic about the type incompatibilities.
11 */
12
13 void matrix_fun(int N, const float x[N][N]);
test1(void)14 void test1(void) {
15 int N = 100;
16 float x[N][N];
17 // FIXME: This is OK in C23 but should be diagnosed as passing incompatible
18 // pointer types in C17 and earlier.
19 matrix_fun(N, x);
20 }
21
22 #define TEST(Expr, Type) _Generic(Expr, Type : 1)
23
test2(void)24 void test2(void) {
25 typedef int array[1];
26 array reg_array;
27 const array const_array;
28
29 // An array and its elements are identically qualified. We have to test this
30 // using pointers to the array and element, because the controlling
31 // expression of _Generic will undergo lvalue conversion, which drops
32 // qualifiers.
33 (void)_Generic(®_array, int (*)[1] : 1);
34 (void)_Generic(®_array[0], int * : 1);
35
36 (void)_Generic(&const_array, const int (*)[1] : 1);
37 (void)_Generic(&const_array[0], const int * : 1);
38
39 // But identical qualification does *not* apply to the _Atomic specifier,
40 // because that's a special case. You cannot apply the _Atomic specifier or
41 // qualifier to an array type directly.
42 _Atomic array atomic_array; // expected-error {{_Atomic cannot be applied to array type 'array'}}
43 _Atomic(array) also_atomic_array; // expected-error {{_Atomic cannot be applied to array type 'array'}}
44
45 // Ensure we support arrays of restrict-qualified pointer types.
46 int *restrict array_of_restricted_ptrs[1];
47 int *restrict md_array_of_restricted_ptrs[1][1];
48 }
49
test3(void)50 void test3(void) {
51 // Validate that we pick the correct composite type for a conditional
52 // operator in the presence of qualifiers.
53 const int const_array[1];
54 int array[1];
55
56 // FIXME: the type here should be `const int (*)[1]`, but for some reason,
57 // Clang is deciding it's `void *`. This relates to N2607 because the
58 // conditional operator is not properly implementing 6.5.15p7 regarding
59 // qualifiers, despite that wording not being touched by this paper.
60 // However, it should get a pedantic diagnostic in C17 about use of
61 // incompatible pointer types.
62 (void)_Generic(1 ? &const_array : &array, const int (*)[1] : 1); /* expected-error {{controlling expression type 'void *' not compatible with any generic association type}}
63 expected-warning {{pointer type mismatch ('const int (*)[1]' and 'int (*)[1]')}}
64 */
65 }
66