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.
38 fn generic<T: 'static>() {
40 let _val: &'static T = mem::zeroed(); //~ ERROR: does not permit zero-initialization
41 let _val: &'static T = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
43 let _val: Wrap<&'static T> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
44 let _val: Wrap<&'static T> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
50 // Things that cannot even be zero.
51 let _val: ! = mem::zeroed(); //~ ERROR: does not permit zero-initialization
52 let _val: ! = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
54 let _val: (i32, !) = mem::zeroed(); //~ ERROR: does not permit zero-initialization
55 let _val: (i32, !) = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
57 let _val: Void = mem::zeroed(); //~ ERROR: does not permit zero-initialization
58 let _val: Void = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
60 let _val: &'static i32 = mem::zeroed(); //~ ERROR: does not permit zero-initialization
61 let _val: &'static i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
63 let _val: Ref = mem::zeroed(); //~ ERROR: does not permit zero-initialization
64 let _val: Ref = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
66 let _val: fn() = mem::zeroed(); //~ ERROR: does not permit zero-initialization
67 let _val: fn() = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
69 let _val: Wrap<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
70 let _val: Wrap<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
72 let _val: WrapEnum<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
73 let _val: WrapEnum<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
75 let _val: Wrap<(RefPair, i32)> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
76 let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
78 let _val: NonNull<i32> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
79 let _val: NonNull<i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
81 let _val: *const dyn Send = mem::zeroed(); //~ ERROR: does not permit zero-initialization
82 let _val: *const dyn Send = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
84 // Things that can be zero, but not uninit.
85 let _val: bool = mem::zeroed();
86 let _val: bool = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
88 let _val: Wrap<char> = mem::zeroed();
89 let _val: Wrap<char> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
91 let _val: NonBig = mem::zeroed();
92 let _val: NonBig = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
94 let _val: Fruit = mem::zeroed();
95 let _val: Fruit = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
98 let _val: &'static i32 = mem::transmute(0usize); //~ ERROR: does not permit zero-initialization
99 let _val: &'static [i32] = mem::transmute((0usize, 0usize)); //~ ERROR: does not permit zero-initialization
100 let _val: NonZeroU32 = mem::transmute(0); //~ ERROR: does not permit zero-initialization
102 // `MaybeUninit` cases
103 let _val: NonNull<i32> = MaybeUninit::zeroed().assume_init(); //~ ERROR: does not permit zero-initialization
104 let _val: NonNull<i32> = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
105 let _val: bool = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
107 // Some more types that should work just fine.
108 let _val: Option<&'static i32> = mem::zeroed();
109 let _val: Option<fn()> = mem::zeroed();
110 let _val: MaybeUninit<&'static i32> = mem::zeroed();
111 let _val: i32 = mem::zeroed();
112 let _val: bool = MaybeUninit::zeroed().assume_init();
113 // Some things that happen to work due to rustc implementation details,
114 // but are not guaranteed to keep working.
115 let _val: i32 = mem::uninitialized();
116 let _val: OneFruit = mem::uninitialized();