1 // This test checks that calling `mem::{uninitialized,zeroed}` with certain types results
4 #![feature(never_type, rustc_attrs)]
6 #![deny(invalid_value)]
8 use std::mem::{self, MaybeUninit};
10 use std::num::NonZeroU32;
14 struct Ref(&'static i32);
15 struct RefPair((&'static i32, i32));
17 struct Wrap<T> { wrapped: T }
18 enum WrapEnum<T> { Wrapped(T) }
20 #[rustc_layout_scalar_valid_range_start(0)]
21 #[rustc_layout_scalar_valid_range_end(128)]
23 pub(crate) struct NonBig(u64);
25 /// A two-variant enum, thus needs a tag and may not remain uninitialized.
31 /// Looks like two variants but really only has one.
37 enum OneFruitNonZero {
47 #[rustc_layout_scalar_valid_range_start(254)]
48 #[rustc_layout_scalar_valid_range_end(1)]
49 pub(crate) struct WrapAroundRange(u8);
52 fn generic<T: 'static>() {
54 let _val: &'static T = mem::zeroed(); //~ ERROR: does not permit zero-initialization
55 let _val: &'static T = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
57 let _val: Wrap<&'static T> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
58 let _val: Wrap<&'static T> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
64 // Things that cannot even be zero.
65 let _val: ! = mem::zeroed(); //~ ERROR: does not permit zero-initialization
66 let _val: ! = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
68 let _val: (i32, !) = mem::zeroed(); //~ ERROR: does not permit zero-initialization
69 let _val: (i32, !) = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
71 let _val: Void = mem::zeroed(); //~ ERROR: does not permit zero-initialization
72 let _val: Void = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
74 let _val: &'static i32 = mem::zeroed(); //~ ERROR: does not permit zero-initialization
75 let _val: &'static i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
77 let _val: Ref = mem::zeroed(); //~ ERROR: does not permit zero-initialization
78 let _val: Ref = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
80 let _val: fn() = mem::zeroed(); //~ ERROR: does not permit zero-initialization
81 let _val: fn() = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
83 let _val: Wrap<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
84 let _val: Wrap<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
86 let _val: WrapEnum<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
87 let _val: WrapEnum<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
89 let _val: Wrap<(RefPair, i32)> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
90 let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
92 let _val: NonNull<i32> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
93 let _val: NonNull<i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
95 let _val: (NonZeroU32, i32) = mem::zeroed(); //~ ERROR: does not permit zero-initialization
96 let _val: (NonZeroU32, i32) = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
98 let _val: *const dyn Send = mem::zeroed(); //~ ERROR: does not permit zero-initialization
99 let _val: *const dyn Send = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
101 let _val: [fn(); 2] = mem::zeroed(); //~ ERROR: does not permit zero-initialization
102 let _val: [fn(); 2] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
104 let _val: TwoUninhabited = mem::zeroed(); //~ ERROR: does not permit zero-initialization
105 let _val: TwoUninhabited = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
107 let _val: OneFruitNonZero = mem::zeroed(); //~ ERROR: does not permit zero-initialization
108 let _val: OneFruitNonZero = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
110 // Things that can be zero, but not uninit.
111 let _val: bool = mem::zeroed();
112 let _val: bool = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
114 let _val: Wrap<char> = mem::zeroed();
115 let _val: Wrap<char> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
117 let _val: NonBig = mem::zeroed();
118 let _val: NonBig = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
120 let _val: Fruit = mem::zeroed();
121 let _val: Fruit = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
123 let _val: [bool; 2] = mem::zeroed();
124 let _val: [bool; 2] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
126 let _val: i32 = mem::zeroed();
127 let _val: i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
129 let _val: f32 = mem::zeroed();
130 let _val: f32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
132 let _val: *const () = mem::zeroed();
133 let _val: *const () = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
135 let _val: *const [()] = mem::zeroed();
136 let _val: *const [()] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
138 let _val: WrapAroundRange = mem::zeroed();
139 let _val: WrapAroundRange = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
141 // Things where 0 is okay due to rustc implementation details,
142 // but that are not guaranteed to keep working.
143 let _val: Result<i32, i32> = mem::zeroed();
144 let _val: Result<i32, i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
146 // Some things that happen to be UB-free due to rustc implementation details,
147 // but are not guaranteed to keep working.
148 let _val: OneFruit = mem::zeroed();
149 let _val: OneFruit = mem::uninitialized();
152 let _val: &'static i32 = mem::transmute(0usize); //~ ERROR: does not permit zero-initialization
153 let _val: &'static [i32] = mem::transmute((0usize, 0usize)); //~ ERROR: does not permit zero-initialization
154 let _val: NonZeroU32 = mem::transmute(0); //~ ERROR: does not permit zero-initialization
156 // `MaybeUninit` cases
157 let _val: NonNull<i32> = MaybeUninit::zeroed().assume_init(); //~ ERROR: does not permit zero-initialization
158 let _val: NonNull<i32> = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
159 let _val: bool = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
161 // Some more types that should work just fine.
162 let _val: Option<&'static i32> = mem::zeroed();
163 let _val: Option<fn()> = mem::zeroed();
164 let _val: MaybeUninit<&'static i32> = mem::zeroed();
165 let _val: bool = MaybeUninit::zeroed().assume_init();
166 let _val: [bool; 0] = MaybeUninit::uninit().assume_init();
167 let _val: [!; 0] = MaybeUninit::zeroed().assume_init();