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 {
48 fn generic<T: 'static>() {
50 let _val: &'static T = mem::zeroed(); //~ ERROR: does not permit zero-initialization
51 let _val: &'static T = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
53 let _val: Wrap<&'static T> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
54 let _val: Wrap<&'static T> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
60 // Things that cannot even be zero.
61 let _val: ! = mem::zeroed(); //~ ERROR: does not permit zero-initialization
62 let _val: ! = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
64 let _val: (i32, !) = mem::zeroed(); //~ ERROR: does not permit zero-initialization
65 let _val: (i32, !) = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
67 let _val: Void = mem::zeroed(); //~ ERROR: does not permit zero-initialization
68 let _val: Void = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
70 let _val: &'static i32 = mem::zeroed(); //~ ERROR: does not permit zero-initialization
71 let _val: &'static i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
73 let _val: Ref = mem::zeroed(); //~ ERROR: does not permit zero-initialization
74 let _val: Ref = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
76 let _val: fn() = mem::zeroed(); //~ ERROR: does not permit zero-initialization
77 let _val: fn() = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
79 let _val: Wrap<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
80 let _val: Wrap<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
82 let _val: WrapEnum<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
83 let _val: WrapEnum<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
85 let _val: Wrap<(RefPair, i32)> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
86 let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
88 let _val: NonNull<i32> = mem::zeroed(); //~ ERROR: does not permit zero-initialization
89 let _val: NonNull<i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
91 let _val: *const dyn Send = mem::zeroed(); //~ ERROR: does not permit zero-initialization
92 let _val: *const dyn Send = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
94 let _val: [fn(); 2] = mem::zeroed(); //~ ERROR: does not permit zero-initialization
95 let _val: [fn(); 2] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
97 let _val: TwoUninhabited = mem::zeroed(); //~ ERROR: does not permit zero-initialization
98 let _val: TwoUninhabited = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
100 let _val: OneFruitNonZero = mem::zeroed(); //~ ERROR: does not permit zero-initialization
101 let _val: OneFruitNonZero = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
103 // Things that can be zero, but not uninit.
104 let _val: bool = mem::zeroed();
105 let _val: bool = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
107 let _val: Wrap<char> = mem::zeroed();
108 let _val: Wrap<char> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
110 let _val: NonBig = mem::zeroed();
111 let _val: NonBig = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
113 let _val: Fruit = mem::zeroed();
114 let _val: Fruit = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
116 let _val: [bool; 2] = mem::zeroed();
117 let _val: [bool; 2] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
119 let _val: i32 = mem::zeroed();
120 let _val: i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
122 let _val: f32 = mem::zeroed();
123 let _val: f32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
125 let _val: *const () = mem::zeroed();
126 let _val: *const () = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
128 let _val: *const [()] = mem::zeroed();
129 let _val: *const [()] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
131 // Things where 0 is okay due to rustc implementation details,
132 // but that are not guaranteed to keep working.
133 let _val: Result<i32, i32> = mem::zeroed();
134 let _val: Result<i32, i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
136 // Some things that happen to work due to rustc implementation details,
137 // but are not guaranteed to keep working.
138 let _val: OneFruit = mem::zeroed();
139 let _val: OneFruit = mem::uninitialized();
142 let _val: &'static i32 = mem::transmute(0usize); //~ ERROR: does not permit zero-initialization
143 let _val: &'static [i32] = mem::transmute((0usize, 0usize)); //~ ERROR: does not permit zero-initialization
144 let _val: NonZeroU32 = mem::transmute(0); //~ ERROR: does not permit zero-initialization
146 // `MaybeUninit` cases
147 let _val: NonNull<i32> = MaybeUninit::zeroed().assume_init(); //~ ERROR: does not permit zero-initialization
148 let _val: NonNull<i32> = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
149 let _val: bool = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized
151 // Some more types that should work just fine.
152 let _val: Option<&'static i32> = mem::zeroed();
153 let _val: Option<fn()> = mem::zeroed();
154 let _val: MaybeUninit<&'static i32> = mem::zeroed();
155 let _val: bool = MaybeUninit::zeroed().assume_init();
156 let _val: [bool; 0] = MaybeUninit::uninit().assume_init();
157 let _val: [!; 0] = MaybeUninit::zeroed().assume_init();