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-rw-r--r--src/test/ui/lint/invalid_value.rs169
1 files changed, 169 insertions, 0 deletions
diff --git a/src/test/ui/lint/invalid_value.rs b/src/test/ui/lint/invalid_value.rs
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+// 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,
+}
+
+enum OneFruitNonZero {
+ Apple(!),
+ Banana(NonZeroU32),
+}
+
+enum TwoUninhabited {
+ A(!),
+ B(Void),
+}
+
+#[rustc_layout_scalar_valid_range_start(254)]
+#[rustc_layout_scalar_valid_range_end(1)]
+pub(crate) struct WrapAroundRange(u8);
+
+#[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: (NonZeroU32, i32) = mem::zeroed(); //~ ERROR: does not permit zero-initialization
+ let _val: (NonZeroU32, 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
+
+ let _val: TwoUninhabited = mem::zeroed(); //~ ERROR: does not permit zero-initialization
+ let _val: TwoUninhabited = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
+
+ let _val: OneFruitNonZero = mem::zeroed(); //~ ERROR: does not permit zero-initialization
+ let _val: OneFruitNonZero = 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
+
+ let _val: i32 = mem::zeroed();
+ let _val: i32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
+
+ let _val: f32 = mem::zeroed();
+ let _val: f32 = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
+
+ let _val: *const () = mem::zeroed();
+ let _val: *const () = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
+
+ let _val: *const [()] = mem::zeroed();
+ let _val: *const [()] = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
+
+ let _val: WrapAroundRange = mem::zeroed();
+ let _val: WrapAroundRange = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
+
+ // Things where 0 is okay due to rustc implementation details,
+ // but that are not guaranteed to keep working.
+ let _val: Result<i32, i32> = mem::zeroed();
+ let _val: Result<i32, i32> = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized
+
+ // Some things that happen to be UB-free due to rustc implementation details,
+ // but are not guaranteed to keep working.
+ let _val: OneFruit = mem::zeroed();
+ let _val: OneFruit = mem::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: bool = MaybeUninit::zeroed().assume_init();
+ let _val: [bool; 0] = MaybeUninit::uninit().assume_init();
+ let _val: [!; 0] = MaybeUninit::zeroed().assume_init();
+ }
+}