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Commit | Line | Data |
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f20569fa | 1 | #![feature(stmt_expr_attributes)] |
f2b60f7d | 2 | #![allow(clippy::let_unit_value, invalid_value)] |
f20569fa | 3 | |
353b0b11 FG |
4 | use std::mem::MaybeUninit; |
5 | ||
6 | union MyOwnMaybeUninit { | |
7 | value: u8, | |
8 | uninit: (), | |
9 | } | |
f20569fa XL |
10 | |
11 | fn main() { | |
12 | let _: usize = unsafe { MaybeUninit::uninit().assume_init() }; | |
781aab86 FG |
13 | //~^ ERROR: this call for this type may be undefined behavior |
14 | //~| NOTE: `#[deny(clippy::uninit_assumed_init)]` on by default | |
f20569fa | 15 | |
353b0b11 | 16 | // This is OK, because ZSTs do not contain data. |
f20569fa XL |
17 | let _: () = unsafe { MaybeUninit::uninit().assume_init() }; |
18 | ||
19 | // This is OK, because `MaybeUninit` allows uninitialized data. | |
20 | let _: MaybeUninit<usize> = unsafe { MaybeUninit::uninit().assume_init() }; | |
21 | ||
49aad941 | 22 | // This is OK, because all constituent types are uninit-compatible. |
f20569fa XL |
23 | let _: (MaybeUninit<usize>, MaybeUninit<bool>) = unsafe { MaybeUninit::uninit().assume_init() }; |
24 | ||
49aad941 | 25 | // This is OK, because all constituent types are uninit-compatible. |
f20569fa | 26 | let _: (MaybeUninit<usize>, [MaybeUninit<bool>; 2]) = unsafe { MaybeUninit::uninit().assume_init() }; |
cdc7bbd5 | 27 | |
353b0b11 FG |
28 | // This is OK, because our own MaybeUninit is just as fine as the one from core. |
29 | let _: MyOwnMaybeUninit = unsafe { MaybeUninit::uninit().assume_init() }; | |
30 | ||
31 | // This is OK, because empty arrays don't contain data. | |
32 | let _: [u8; 0] = unsafe { MaybeUninit::uninit().assume_init() }; | |
33 | ||
cdc7bbd5 | 34 | // Was a false negative. |
353b0b11 | 35 | let _: usize = unsafe { MaybeUninit::uninit().assume_init() }; |
781aab86 | 36 | //~^ ERROR: this call for this type may be undefined behavior |
353b0b11 FG |
37 | |
38 | polymorphic::<()>(); | |
39 | polymorphic_maybe_uninit_array::<10>(); | |
40 | polymorphic_maybe_uninit::<u8>(); | |
41 | ||
42 | fn polymorphic<T>() { | |
43 | // We are conservative around polymorphic types. | |
44 | let _: T = unsafe { MaybeUninit::uninit().assume_init() }; | |
781aab86 | 45 | //~^ ERROR: this call for this type may be undefined behavior |
353b0b11 FG |
46 | } |
47 | ||
48 | fn polymorphic_maybe_uninit_array<const N: usize>() { | |
49 | // While the type is polymorphic, MaybeUninit<u8> is not. | |
50 | let _: [MaybeUninit<u8>; N] = unsafe { MaybeUninit::uninit().assume_init() }; | |
51 | } | |
52 | ||
53 | fn polymorphic_maybe_uninit<T>() { | |
54 | // The entire type is polymorphic, but it's wrapped in a MaybeUninit. | |
55 | let _: MaybeUninit<T> = unsafe { MaybeUninit::uninit().assume_init() }; | |
56 | } | |
f20569fa | 57 | } |