2 // ignore-tidy-linelength
7 // normalize-stderr-test "offset \d+" -> "offset N"
8 // normalize-stderr-test "alloc\d+" -> "allocN"
9 // normalize-stderr-test "size \d+" -> "size N"
11 /// A newtype wrapper to prevent MIR generation from inserting reborrows that would affect the error
12 /// message. Use this whenever the message is "any use of this value will cause an error" instead of
13 /// "it is undefined behavior to use this value".
18 union MaybeUninit<T: Copy> {
24 impl Trait for bool {}
26 // custom unsized type
29 // custom unsized type with sized fields
30 struct MySlice<T: ?Sized>(bool, T);
31 type MySliceBool = MySlice<[bool]>;
35 const STR_VALID: &str = unsafe { mem::transmute((&42u8, 1usize)) };
37 const STR_TOO_LONG: &str = unsafe { mem::transmute((&42u8, 999usize)) };
38 //~^ ERROR it is undefined behavior to use this value
39 const NESTED_STR_MUCH_TOO_LONG: (&str,) = (unsafe { mem::transmute((&42, usize::MAX)) },);
40 //~^ ERROR it is undefined behavior to use this value
42 const STR_LENGTH_PTR: &str = unsafe { mem::transmute((&42u8, &3)) };
43 //~^ ERROR any use of this value will cause an error
44 //~| WARN this was previously accepted by the compiler but is being phased out
45 // bad str in user-defined unsized type
46 const MY_STR_LENGTH_PTR: &MyStr = unsafe { mem::transmute((&42u8, &3)) };
47 //~^ ERROR any use of this value will cause an error
48 //~| WARN this was previously accepted by the compiler but is being phased out
49 const MY_STR_MUCH_TOO_LONG: &MyStr = unsafe { mem::transmute((&42u8, usize::MAX)) };
50 //~^ ERROR it is undefined behavior to use this value
53 const STR_NO_INIT: &str = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
54 //~^ ERROR it is undefined behavior to use this value
55 // uninitialized byte in user-defined str-like
56 const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
57 //~^ ERROR it is undefined behavior to use this value
61 const SLICE_VALID: &[u8] = unsafe { mem::transmute((&42u8, 1usize)) };
62 // bad slice: length uninit
63 const SLICE_LENGTH_UNINIT: &[u8] = unsafe {
64 //~^ ERROR it is undefined behavior to use this value
65 let uninit_len = MaybeUninit::<usize> { uninit: () };
66 mem::transmute((42, uninit_len))
68 // bad slice: length too big
69 const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
70 //~^ ERROR it is undefined behavior to use this value
71 // bad slice: length computation overflows
72 const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, isize::MAX)) };
73 //~^ ERROR it is undefined behavior to use this value
74 // bad slice: length not an int
75 const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
76 //~^ ERROR any use of this value will cause an error
77 //~| WARN this was previously accepted by the compiler but is being phased out
78 // bad slice box: length too big
79 const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999usize)) };
80 //~^ ERROR it is undefined behavior to use this value
81 // bad slice box: length not an int
82 const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
83 //~^ ERROR any use of this value will cause an error
84 //~| WARN this was previously accepted by the compiler but is being phased out
86 // bad data *inside* the slice
87 const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
88 //~^ ERROR it is undefined behavior to use this value
89 //~| ERROR any use of this value will cause an error
90 //~| WARNING this was previously accepted
93 const MYSLICE_GOOD: &MySliceBool = &MySlice(true, [false]);
94 // bad: sized field is not okay
95 const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
96 //~^ ERROR it is undefined behavior to use this value
97 //~| ERROR any use of this value will cause an error
98 //~| WARNING this was previously accepted
99 // bad: unsized part is not okay
100 const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
101 //~^ ERROR it is undefined behavior to use this value
102 //~| ERROR any use of this value will cause an error
103 //~| WARNING this was previously accepted
106 const RAW_SLICE_VALID: *const [u8] = unsafe { mem::transmute((&42u8, 1usize)) }; // ok
107 const RAW_SLICE_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, 999usize)) }; // ok because raw
108 const RAW_SLICE_MUCH_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, usize::MAX)) }; // ok because raw
109 const RAW_SLICE_LENGTH_UNINIT: *const [u8] = unsafe {
110 //~^ ERROR it is undefined behavior to use this value
111 let uninit_len = MaybeUninit::<usize> { uninit: () };
112 mem::transmute((42, uninit_len))
117 const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u8))) };
118 //~^ ERROR it is undefined behavior to use this value
120 const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u64))) };
121 //~^ ERROR it is undefined behavior to use this value
123 const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, 4usize))) };
124 //~^ ERROR it is undefined behavior to use this value
125 const TRAIT_OBJ_UNALIGNED_VTABLE: &dyn Trait = unsafe { mem::transmute((&92u8, &[0u8; 128])) };
126 //~^ ERROR it is undefined behavior to use this value
127 const TRAIT_OBJ_BAD_DROP_FN_NULL: &dyn Trait = unsafe { mem::transmute((&92u8, &[0usize; 8])) };
128 //~^ ERROR it is undefined behavior to use this value
129 const TRAIT_OBJ_BAD_DROP_FN_INT: &dyn Trait = unsafe { mem::transmute((&92u8, &[1usize; 8])) };
130 //~^ ERROR it is undefined behavior to use this value
131 const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &[&42u8; 8]))) };
132 //~^ ERROR it is undefined behavior to use this value
134 // bad data *inside* the trait object
135 const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) };
136 //~^ ERROR it is undefined behavior to use this value
138 // # raw trait object
139 const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) };
140 //~^ ERROR it is undefined behavior to use this value
141 const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
142 //~^ ERROR it is undefined behavior to use this value
143 const RAW_TRAIT_OBJ_CONTENT_INVALID: *const dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) } as *const dyn Trait; // ok because raw
145 // Const eval fails for these, so they need to be statics to error.
146 static mut RAW_TRAIT_OBJ_VTABLE_NULL_THROUGH_REF: *const dyn Trait = unsafe {
147 mem::transmute::<_, &dyn Trait>((&92u8, 0usize))
148 //~^ ERROR could not evaluate static initializer
150 static mut RAW_TRAIT_OBJ_VTABLE_INVALID_THROUGH_REF: *const dyn Trait = unsafe {
151 mem::transmute::<_, &dyn Trait>((&92u8, &3u64))
152 //~^ ERROR could not evaluate static initializer