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
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:16:1
|
LL | const UNALIGNED: &u16 = unsafe { mem::transmute(&[0u8; 4]) };
| ^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned reference (required 2 byte alignment but found 1)
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:20:1
|
LL | const UNALIGNED_BOX: Box<u16> = unsafe { mem::transmute(&[0u8; 4]) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned box (required 2 byte alignment but found 1)
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:24:1
|
LL | const NULL: &u16 = unsafe { mem::transmute(0usize) };
| ^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null reference
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:27:1
|
LL | const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null box
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:34:1
|
LL | const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
|
= help: this code performed an operation that depends on the underlying bytes representing a pointer
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:37:39
|
LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
|
= help: this code performed an operation that depends on the underlying bytes representing a pointer
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
note: erroneous constant used
--> $DIR/ub-ref-ptr.rs:37:38
|
LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:40:86
|
LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
| ^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
|
= help: this code performed an operation that depends on the underlying bytes representing a pointer
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
note: erroneous constant used
--> $DIR/ub-ref-ptr.rs:40:85
|
LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
| ^^^^^^^^^^^^^^^^^^^^^
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:43:1
|
LL | const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (0x539[noalloc] has no provenance)
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:46:1
|
LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling box (0x539[noalloc] has no provenance)
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:49:41
|
LL | const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:53:1
|
LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a function pointer
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:55:38
|
LL | const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:58:1
|
LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0xd[noalloc], but expected a function pointer
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:60:1
|
LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered alloc41, but expected a function pointer
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error: accessing memory with alignment 1, but alignment 4 is required
--> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #68585 <https://github.com/rust-lang/rust/issues/104616>
note: inside `std::ptr::read::<u32>`
--> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
note: inside `ptr::const_ptr::<impl *const u32>::read`
--> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
note: inside `UNALIGNED_READ`
--> $DIR/ub-ref-ptr.rs:67:5
|
LL | ptr.read();
| ^^^^^^^^^^
= note: `#[deny(invalid_alignment)]` on by default
error: aborting due to 15 previous errors
For more information about this error, try `rustc --explain E0080`.
Future incompatibility report: Future breakage diagnostic:
error: accessing memory with alignment 1, but alignment 4 is required
--> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #68585 <https://github.com/rust-lang/rust/issues/104616>
note: inside `std::ptr::read::<u32>`
--> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
note: inside `ptr::const_ptr::<impl *const u32>::read`
--> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
note: inside `UNALIGNED_READ`
--> $DIR/ub-ref-ptr.rs:67:5
|
LL | ptr.read();
| ^^^^^^^^^^
= note: `#[deny(invalid_alignment)]` on by default
|
