1 // ignore-tidy-linelength
2 // This test checks that calling `mem::{uninitialized,zeroed}` with certain types results
5 #![feature(never_type, rustc_attrs)]
7 #![deny(invalid_value)]
9 use std::mem::{self, MaybeUninit};
10 use std::ptr::NonNull;
11 use std::num::NonZeroU32;
15 struct Ref(&'static i32);
16 struct RefPair((&'static i32, i32));
18 struct Wrap<T> { wrapped: T }
19 enum WrapEnum<T> { Wrapped(T) }
21 #[rustc_layout_scalar_valid_range_start(0)]
22 #[rustc_layout_scalar_valid_range_end(128)]
24 pub(crate) struct NonBig(u64);
26 /// A two-variant enum, thus needs a tag and may not remain uninitialized.
32 /// Looks like two variants but really only has one.
39 fn generic<T: 'static>() {
41 let _val: &'static T = mem::zeroed(); //~ ERROR: does not permit zero-initialization
42 let _val: &'static T = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
44 let _val: Wrap<&'static T> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
45 let _val: Wrap<&'static T> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
51 // Things that cannot even be zero.
52 let _val: ! = mem::zeroed(); //~ ERROR: does not permit zero-initialization
53 let _val: ! = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
55 let _val: (i32, !) = mem::zeroed(); //~ ERROR: does not permit zero-initialization
56 let _val: (i32, !) = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
58 let _val: Void = mem::zeroed(); //~ ERROR: does not permit zero-initialization
59 let _val: Void = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
61 let _val: &'static i32 = mem::zeroed(); //~ ERROR: does not permit zero-initialization
62 let _val: &'static i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
64 let _val: Ref = mem::zeroed(); //~ ERROR: does not permit zero-initialization
65 let _val: Ref = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
67 let _val: fn() = mem::zeroed(); //~ ERROR: does not permit zero-initialization
68 let _val: fn() = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
70 let _val: Wrap<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
71 let _val: Wrap<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
73 let _val: WrapEnum<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
74 let _val: WrapEnum<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
76 let _val: Wrap<(RefPair, i32)> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
77 let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
79 let _val: NonNull<i32> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
80 let _val: NonNull<i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
82 let _val: *const dyn Send = mem::zeroed(); //~ ERROR: does not permit zero-initialization
83 let _val: *const dyn Send = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
85 // Things that can be zero, but not uninit.
86 let _val: bool = mem::zeroed();
87 let _val: bool = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
89 let _val: Wrap<char> = mem::zeroed();
90 let _val: Wrap<char> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
92 let _val: NonBig = mem::zeroed();
93 let _val: NonBig = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
95 let _val: Fruit = mem::zeroed();
96 let _val: Fruit = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
99 let _val: &'static i32 = mem::transmute(0usize); //~ ERROR: does not permit zero-initialization
100 let _val: &'static [i32] = mem::transmute((0usize, 0usize)); //~ ERROR: does not permit zero-initialization
101 let _val: NonZeroU32 = mem::transmute(0); //~ ERROR: does not permit zero-initialization
103 // `MaybeUninit` cases
104 let _val: NonNull<i32> = MaybeUninit::zeroed().assume_init(); //~ ERROR: does not permit zero-initialization
105 let _val: NonNull<i32> = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
106 let _val: bool = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
108 // Some more types that should work just fine.
109 let _val: Option<&'static i32> = mem::zeroed();
110 let _val: Option<fn()> = mem::zeroed();
111 let _val: MaybeUninit<&'static i32> = mem::zeroed();
112 let _val: i32 = mem::zeroed();
113 let _val: bool = MaybeUninit::zeroed().assume_init();
114 // Some things that happen to work due to rustc implementation details,
115 // but are not guaranteed to keep working.
116 let _val: i32 = mem::uninitialized();
117 let _val: OneFruit = mem::uninitialized();