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
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
// stderr-per-bitwidth
// ignore-tidy-linelength
#![allow(unused)]
use std::mem;
// normalize-stderr-test "offset \d+" -> "offset N"
// normalize-stderr-test "alloc\d+" -> "allocN"
// normalize-stderr-test "size \d+" -> "size N"
/// A newtype wrapper to prevent MIR generation from inserting reborrows that would affect the error
/// message. Use this whenever the message is "any use of this value will cause an error" instead of
/// "it is undefined behavior to use this value".
#[repr(transparent)]
struct W<T>(T);
#[repr(C)]
union MaybeUninit<T: Copy> {
uninit: (),
init: T,
}
trait Trait {}
impl Trait for bool {}
// custom unsized type
struct MyStr(str);
// custom unsized type with sized fields
struct MySlice<T: ?Sized>(bool, T);
type MySliceBool = MySlice<[bool]>;
// # str
// OK
const STR_VALID: &str = unsafe { mem::transmute((&42u8, 1usize)) };
// bad str
const STR_TOO_LONG: &str = unsafe { mem::transmute((&42u8, 999usize)) };
//~^ ERROR it is undefined behavior to use this value
const NESTED_STR_MUCH_TOO_LONG: (&str,) = (unsafe { mem::transmute((&42, usize::MAX)) },);
//~^ ERROR it is undefined behavior to use this value
// bad str
const STR_LENGTH_PTR: &str = unsafe { mem::transmute((&42u8, &3)) };
//~^ ERROR any use of this value will cause an error
//~| WARN this was previously accepted by the compiler but is being phased out
// bad str in user-defined unsized type
const MY_STR_LENGTH_PTR: &MyStr = unsafe { mem::transmute((&42u8, &3)) };
//~^ ERROR any use of this value will cause an error
//~| WARN this was previously accepted by the compiler but is being phased out
const MY_STR_MUCH_TOO_LONG: &MyStr = unsafe { mem::transmute((&42u8, usize::MAX)) };
//~^ ERROR it is undefined behavior to use this value
// uninitialized byte
const STR_NO_INIT: &str = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
//~^ ERROR it is undefined behavior to use this value
// uninitialized byte in user-defined str-like
const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
//~^ ERROR it is undefined behavior to use this value
// # slice
// OK
const SLICE_VALID: &[u8] = unsafe { mem::transmute((&42u8, 1usize)) };
// bad slice: length uninit
const SLICE_LENGTH_UNINIT: &[u8] = unsafe {
//~^ ERROR evaluation of constant value failed
//~| uninitialized
let uninit_len = MaybeUninit::<usize> { uninit: () };
mem::transmute((42, uninit_len))
};
// bad slice: length too big
const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
//~^ ERROR it is undefined behavior to use this value
// bad slice: length computation overflows
const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, isize::MAX)) };
//~^ ERROR it is undefined behavior to use this value
// bad slice: length not an int
const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
//~^ ERROR any use of this value will cause an error
//~| WARN this was previously accepted by the compiler but is being phased out
// bad slice box: length too big
const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999usize)) };
//~^ ERROR it is undefined behavior to use this value
// bad slice box: length not an int
const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
//~^ ERROR any use of this value will cause an error
//~| WARN this was previously accepted by the compiler but is being phased out
// bad data *inside* the slice
const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
//~^ ERROR it is undefined behavior to use this value
//~| ERROR any use of this value will cause an error
//~| WARNING this was previously accepted
// good MySliceBool
const MYSLICE_GOOD: &MySliceBool = &MySlice(true, [false]);
// bad: sized field is not okay
const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
//~^ ERROR it is undefined behavior to use this value
//~| ERROR any use of this value will cause an error
//~| WARNING this was previously accepted
// bad: unsized part is not okay
const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
//~^ ERROR it is undefined behavior to use this value
//~| ERROR any use of this value will cause an error
//~| WARNING this was previously accepted
// # raw slice
const RAW_SLICE_VALID: *const [u8] = unsafe { mem::transmute((&42u8, 1usize)) }; // ok
const RAW_SLICE_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, 999usize)) }; // ok because raw
const RAW_SLICE_MUCH_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, usize::MAX)) }; // ok because raw
const RAW_SLICE_LENGTH_UNINIT: *const [u8] = unsafe {
//~^ ERROR evaluation of constant value failed
//~| uninitialized
let uninit_len = MaybeUninit::<usize> { uninit: () };
mem::transmute((42, uninit_len))
};
// # trait object
// bad trait object
const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u8))) };
//~^ ERROR it is undefined behavior to use this value
//~| expected a vtable
// bad trait object
const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u64))) };
//~^ ERROR it is undefined behavior to use this value
//~| expected a vtable
// bad trait object
const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, 4usize))) };
//~^ ERROR it is undefined behavior to use this value
//~| expected a vtable
const TRAIT_OBJ_UNALIGNED_VTABLE: &dyn Trait = unsafe { mem::transmute((&92u8, &[0u8; 128])) };
//~^ ERROR evaluation of constant value failed
//~| does not point to a vtable
const TRAIT_OBJ_BAD_DROP_FN_NULL: &dyn Trait = unsafe { mem::transmute((&92u8, &[0usize; 8])) };
//~^ ERROR evaluation of constant value failed
//~| does not point to a vtable
const TRAIT_OBJ_BAD_DROP_FN_INT: &dyn Trait = unsafe { mem::transmute((&92u8, &[1usize; 8])) };
//~^ ERROR evaluation of constant value failed
//~| does not point to a vtable
const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &[&42u8; 8]))) };
//~^ ERROR it is undefined behavior to use this value
//~| expected a vtable
// bad data *inside* the trait object
const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) };
//~^ ERROR it is undefined behavior to use this value
//~| expected a boolean
// # raw trait object
const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) };
//~^ ERROR it is undefined behavior to use this value
const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
//~^ ERROR it is undefined behavior to use this value
const RAW_TRAIT_OBJ_CONTENT_INVALID: *const dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) } as *const dyn Trait; // ok because raw
// Const eval fails for these, so they need to be statics to error.
static mut RAW_TRAIT_OBJ_VTABLE_NULL_THROUGH_REF: *const dyn Trait = unsafe {
mem::transmute::<_, &dyn Trait>((&92u8, 0usize))
//~^ ERROR could not evaluate static initializer
};
static mut RAW_TRAIT_OBJ_VTABLE_INVALID_THROUGH_REF: *const dyn Trait = unsafe {
mem::transmute::<_, &dyn Trait>((&92u8, &3u64))
//~^ ERROR could not evaluate static initializer
};
fn main() {}
|
