src/test/ui/consts/const-eval/ub-wide-ptr.rs

   1 // ignore-tidy-linelength
   2 #![allow(unused)]
   3 #![allow(const_err)] // make sure we cannot allow away the errors tested here
   4
   5 use std::mem;
   6
   7 // normalize-stderr-test "offset \d+" -> "offset N"
   8 // normalize-stderr-test "alloc\d+" -> "allocN"
   9 // normalize-stderr-test "size \d+" -> "size N"
  10
  11 #[repr(C)]
  12 union MaybeUninit<T: Copy> {
  13     uninit: (),
  14     init: T,
  15 }
  16
  17 trait Trait {}
  18 impl Trait for bool {}
  19
  20 // custom unsized type
  21 struct MyStr(str);
  22
  23 // custom unsized type with sized fields
  24 struct MySlice<T: ?Sized>(bool, T);
  25 type MySliceBool = MySlice<[bool]>;
  26
  27 // # str
  28 // OK
  29 const STR_VALID: &str = unsafe { mem::transmute((&42u8, 1usize)) };
  30 // bad str
  31 const STR_TOO_LONG: &str = unsafe { mem::transmute((&42u8, 999usize)) };
  32 //~^ ERROR it is undefined behavior to use this value
  33 const NESTED_STR_MUCH_TOO_LONG: (&str,) = (unsafe { mem::transmute((&42, usize::MAX)) },);
  34 //~^ ERROR it is undefined behavior to use this value
  35 // bad str
  36 const STR_LENGTH_PTR: &str = unsafe { mem::transmute((&42u8, &3)) };
  37 //~^ ERROR it is undefined behavior to use this value
  38 // bad str in user-defined unsized type
  39 const MY_STR_LENGTH_PTR: &MyStr = unsafe { mem::transmute((&42u8, &3)) };
  40 //~^ ERROR it is undefined behavior to use this value
  41 const MY_STR_MUCH_TOO_LONG: &MyStr = unsafe { mem::transmute((&42u8, usize::MAX)) };
  42 //~^ ERROR it is undefined behavior to use this value
  43
  44 // uninitialized byte
  45 const STR_NO_INIT: &str = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
  46 //~^ ERROR it is undefined behavior to use this value
  47 // uninitialized byte in user-defined str-like
  48 const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
  49 //~^ ERROR it is undefined behavior to use this value
  50
  51 // # slice
  52 // OK
  53 const SLICE_VALID: &[u8] = unsafe { mem::transmute((&42u8, 1usize)) };
  54 // bad slice: length uninit
  55 const SLICE_LENGTH_UNINIT: &[u8] = unsafe {
  56 //~^ ERROR it is undefined behavior to use this value
  57     let uninit_len = MaybeUninit::<usize> { uninit: () };
  58     mem::transmute((42, uninit_len))
  59 };
  60 // bad slice: length too big
  61 const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
  62 //~^ ERROR it is undefined behavior to use this value
  63 // bad slice: length not an int
  64 const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
  65 //~^ ERROR it is undefined behavior to use this value
  66 // bad slice box: length too big
  67 const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999usize)) };
  68 //~^ ERROR it is undefined behavior to use this value
  69 // bad slice box: length not an int
  70 const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
  71 //~^ ERROR it is undefined behavior to use this value
  72
  73 // bad data *inside* the slice
  74 const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
  75 //~^ ERROR it is undefined behavior to use this value
  76
  77 // good MySliceBool
  78 const MYSLICE_GOOD: &MySliceBool = &MySlice(true, [false]);
  79 // bad: sized field is not okay
  80 const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
  81 //~^ ERROR it is undefined behavior to use this value
  82 // bad: unsized part is not okay
  83 const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
  84 //~^ ERROR it is undefined behavior to use this value
  85
  86 // # raw slice
  87 const RAW_SLICE_VALID: *const [u8] = unsafe { mem::transmute((&42u8, 1usize)) }; // ok
  88 const RAW_SLICE_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, 999usize)) }; // ok because raw
  89 const RAW_SLICE_MUCH_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, usize::MAX)) }; // ok because raw
  90 const RAW_SLICE_LENGTH_UNINIT: *const [u8] = unsafe {
  91 //~^ ERROR it is undefined behavior to use this value
  92     let uninit_len = MaybeUninit::<usize> { uninit: () };
  93     mem::transmute((42, uninit_len))
  94 };
  95
  96 // # trait object
  97 // bad trait object
  98 const TRAIT_OBJ_SHORT_VTABLE_1: &dyn Trait = unsafe { mem::transmute((&92u8, &3u8)) };
  99 //~^ ERROR it is undefined behavior to use this value
 100 // bad trait object
 101 const TRAIT_OBJ_SHORT_VTABLE_2: &dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
 102 //~^ ERROR it is undefined behavior to use this value
 103 // bad trait object
 104 const TRAIT_OBJ_INT_VTABLE: &dyn Trait = unsafe { mem::transmute((&92u8, 4usize)) };
 105 //~^ ERROR it is undefined behavior to use this value
 106 const TRAIT_OBJ_UNALIGNED_VTABLE: &dyn Trait = unsafe { mem::transmute((&92u8, &[0u8; 128])) };
 107 //~^ ERROR it is undefined behavior to use this value
 108 const TRAIT_OBJ_BAD_DROP_FN_NULL: &dyn Trait = unsafe { mem::transmute((&92u8, &[0usize; 8])) };
 109 //~^ ERROR it is undefined behavior to use this value
 110 const TRAIT_OBJ_BAD_DROP_FN_INT: &dyn Trait = unsafe { mem::transmute((&92u8, &[1usize; 8])) };
 111 //~^ ERROR it is undefined behavior to use this value
 112 const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: &dyn Trait = unsafe { mem::transmute((&92u8, &[&42u8; 8])) };
 113 //~^ ERROR it is undefined behavior to use this value
 114
 115 // bad data *inside* the trait object
 116 const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) };
 117 //~^ ERROR it is undefined behavior to use this value
 118
 119 // # raw trait object
 120 const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) };
 121 //~^ ERROR it is undefined behavior to use this value
 122 const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
 123 //~^ ERROR it is undefined behavior to use this value
 124 const RAW_TRAIT_OBJ_CONTENT_INVALID: *const dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) } as *const dyn Trait; // ok because raw
 125
 126 // Const eval fails for these, so they need to be statics to error.
 127 static mut RAW_TRAIT_OBJ_VTABLE_NULL_THROUGH_REF: *const dyn Trait = unsafe {
 128     mem::transmute::<_, &dyn Trait>((&92u8, 0usize))
 129     //~^ ERROR could not evaluate static initializer
 130 };
 131 static mut RAW_TRAIT_OBJ_VTABLE_INVALID_THROUGH_REF: *const dyn Trait = unsafe {
 132     mem::transmute::<_, &dyn Trait>((&92u8, &3u64))
 133     //~^ ERROR could not evaluate static initializer
 134 };
 135
 136 fn main() {}