diff options
Diffstat (limited to 'src/test/ui/lint/uninitialized-zeroed.rs')
-rw-r--r-- | src/test/ui/lint/uninitialized-zeroed.rs | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/src/test/ui/lint/uninitialized-zeroed.rs b/src/test/ui/lint/uninitialized-zeroed.rs new file mode 100644 index 000000000..5cd323c01 --- /dev/null +++ b/src/test/ui/lint/uninitialized-zeroed.rs @@ -0,0 +1,126 @@ +// This test checks that calling `mem::{uninitialized,zeroed}` with certain types results +// in a lint. + +#![feature(never_type, rustc_attrs)] +#![allow(deprecated)] +#![deny(invalid_value)] + +use std::mem::{self, MaybeUninit}; +use std::ptr::NonNull; +use std::num::NonZeroU32; + +enum Void {} + +struct Ref(&'static i32); +struct RefPair((&'static i32, i32)); + +struct Wrap<T> { wrapped: T } +enum WrapEnum<T> { Wrapped(T) } + +#[rustc_layout_scalar_valid_range_start(0)] +#[rustc_layout_scalar_valid_range_end(128)] +#[repr(transparent)] +pub(crate) struct NonBig(u64); + +/// A two-variant enum, thus needs a tag and may not remain uninitialized. +enum Fruit { + Apple, + Banana, +} + +/// Looks like two variants but really only has one. +enum OneFruit { + Apple(!), + Banana, +} + +#[allow(unused)] +fn generic<T: 'static>() { + unsafe { + let _val: &'static T = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: &'static T = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: Wrap<&'static T> = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: Wrap<&'static T> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + } +} + +fn main() { + unsafe { + // Things that cannot even be zero. + let _val: ! = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: ! = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: (i32, !) = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: (i32, !) = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: Void = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: Void = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: &'static i32 = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: &'static i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: Ref = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: Ref = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: fn() = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: fn() = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: Wrap<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: Wrap<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: WrapEnum<fn()> = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: WrapEnum<fn()> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: Wrap<(RefPair, i32)> = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: NonNull<i32> = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: NonNull<i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: *const dyn Send = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: *const dyn Send = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: [fn(); 2] = mem::zeroed(); //~ ERROR: does not permit zero-initialization + let _val: [fn(); 2] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + // Things that can be zero, but not uninit. + let _val: bool = mem::zeroed(); + let _val: bool = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: Wrap<char> = mem::zeroed(); + let _val: Wrap<char> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: NonBig = mem::zeroed(); + let _val: NonBig = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: Fruit = mem::zeroed(); + let _val: Fruit = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + let _val: [bool; 2] = mem::zeroed(); + let _val: [bool; 2] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + + // Transmute-from-0 + let _val: &'static i32 = mem::transmute(0usize); //~ ERROR: does not permit zero-initialization + let _val: &'static [i32] = mem::transmute((0usize, 0usize)); //~ ERROR: does not permit zero-initialization + let _val: NonZeroU32 = mem::transmute(0); //~ ERROR: does not permit zero-initialization + + // `MaybeUninit` cases + let _val: NonNull<i32> = MaybeUninit::zeroed().assume_init(); //~ ERROR: does not permit zero-initialization + let _val: NonNull<i32> = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized + let _val: bool = MaybeUninit::uninit().assume_init(); //~ ERROR: does not permit being left uninitialized + + // Some more types that should work just fine. + let _val: Option<&'static i32> = mem::zeroed(); + let _val: Option<fn()> = mem::zeroed(); + let _val: MaybeUninit<&'static i32> = mem::zeroed(); + let _val: i32 = mem::zeroed(); + let _val: bool = MaybeUninit::zeroed().assume_init(); + let _val: [bool; 0] = MaybeUninit::uninit().assume_init(); + let _val: [!; 0] = MaybeUninit::zeroed().assume_init(); + // Some things that happen to work due to rustc implementation details, + // but are not guaranteed to keep working. + let _val: i32 = mem::uninitialized(); + let _val: OneFruit = mem::uninitialized(); + } +} |