1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 %s
static_assert(__is_literal(int), "fail");
static_assert(__is_literal_type(int), "fail"); // alternate spelling for GCC
static_assert(__is_literal(void*), "fail");
enum E { E1 };
static_assert(__is_literal(E), "fail");
static_assert(__is_literal(decltype(E1)), "fail");
typedef int IAR[10];
static_assert(__is_literal(IAR), "fail");
typedef int Vector __attribute__((vector_size(16)));
typedef int VectorExt __attribute__((ext_vector_type(4)));
static_assert(__is_literal(Vector), "fail");
static_assert(__is_literal(VectorExt), "fail");
// C++0x [basic.types]p10:
// A type is a literal type if it is:
// [...]
// -- a class type that has all of the following properties:
// -- it has a trivial destructor
// -- every constructor call and full-expression in the
// brace-or-equal-initializers for non-static data members (if an) is
// a constant expression,
// -- it is an aggregate type or has at least one constexpr constructor
// or constructor template that is not a copy or move constructor, and
// [DR1452 adds class types with trivial default constructors to
// this list]
// -- it has all non-static data members and base classes of literal
// types
struct Empty {};
struct LiteralType {
int x;
E e;
IAR arr;
Empty empty;
int method();
};
struct HasDtor { ~HasDtor(); };
class NonAggregate { int x; };
struct NonLiteral { NonLiteral(); };
struct HasNonLiteralBase : NonLiteral {};
struct HasNonLiteralMember { HasDtor x; };
static_assert(__is_literal(Empty), "fail");
static_assert(__is_literal(LiteralType), "fail");
static_assert(__is_literal(NonAggregate), "fail");
static_assert(!__is_literal(NonLiteral), "fail");
static_assert(!__is_literal(HasDtor), "fail");
static_assert(!__is_literal(HasNonLiteralBase), "fail");
static_assert(!__is_literal(HasNonLiteralMember), "fail");
// DR1361 removes the brace-or-equal-initializer bullet so that we can allow:
extern int f(); // expected-note {{here}}
struct HasNonConstExprMemInit {
int x = f(); // expected-note {{non-constexpr function}}
constexpr HasNonConstExprMemInit() {} // expected-error {{never produces a constant expression}}
constexpr HasNonConstExprMemInit(int y) : x(y) {} // ok
};
static_assert(__is_literal(HasNonConstExprMemInit), "fail");
class HasConstExprCtor {
int x;
public:
constexpr HasConstExprCtor(int x) : x(x) {}
};
template <typename T> class HasConstExprCtorTemplate {
T x;
public:
template <typename U> constexpr HasConstExprCtorTemplate(U y) : x(y) {}
};
template <typename T> class HasConstExprCtorT {
constexpr HasConstExprCtorT(T) {}
};
static_assert(__is_literal(HasConstExprCtor), "fail");
static_assert(__is_literal(HasConstExprCtorTemplate<int>), "fail");
static_assert(__is_literal(HasConstExprCtorT<NonLiteral>), "fail");
#if __cplusplus >= 202003L
namespace GH77924 {
struct A { A(); };
template <class T>
struct opt {
union Data {
constexpr Data() : x{} {}
constexpr ~Data() {}
char x;
T data;
};
constexpr opt() : data{} {}
constexpr ~opt() { if (engaged) data.data.~T(); }
Data data;
bool engaged = false;
};
consteval void foo() {
opt<A> a;
}
void test() {
foo();
}
}
#endif
|
