79 lines
1.7 KiB
Rust
79 lines
1.7 KiB
Rust
//@ check-pass
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#![feature(derive_coerce_pointee)]
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#[derive(core::marker::CoercePointee)]
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#[repr(transparent)]
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pub struct Ptr<'a, #[pointee] T: OnDrop + ?Sized, X> {
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data: &'a mut T,
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x: core::marker::PhantomData<X>,
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}
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pub trait OnDrop {
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fn on_drop(&mut self);
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}
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#[derive(core::marker::CoercePointee)]
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#[repr(transparent)]
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pub struct Ptr2<'a, #[pointee] T: ?Sized, X>
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where
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T: OnDrop,
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{
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data: &'a mut T,
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x: core::marker::PhantomData<X>,
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}
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pub trait MyTrait<T: ?Sized> {}
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#[derive(core::marker::CoercePointee)]
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#[repr(transparent)]
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pub struct Ptr3<'a, #[pointee] T: ?Sized, X>
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where
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T: MyTrait<T>,
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{
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data: &'a mut T,
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x: core::marker::PhantomData<X>,
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}
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#[derive(core::marker::CoercePointee)]
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#[repr(transparent)]
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pub struct Ptr4<'a, #[pointee] T: MyTrait<T> + ?Sized, X> {
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data: &'a mut T,
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x: core::marker::PhantomData<X>,
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}
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#[derive(core::marker::CoercePointee)]
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#[repr(transparent)]
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pub struct Ptr5<'a, #[pointee] T: ?Sized, X>
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where
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Ptr5Companion<T>: MyTrait<T>,
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Ptr5Companion2: MyTrait<T>,
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{
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data: &'a mut T,
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x: core::marker::PhantomData<X>,
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}
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pub struct Ptr5Companion<T: ?Sized>(core::marker::PhantomData<T>);
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pub struct Ptr5Companion2;
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#[derive(core::marker::CoercePointee)]
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#[repr(transparent)]
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pub struct Ptr6<'a, #[pointee] T: ?Sized, X: MyTrait<T> = (), const PARAM: usize = 0> {
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data: &'a mut T,
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x: core::marker::PhantomData<X>,
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}
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// a reduced example from https://lore.kernel.org/all/20240402-linked-list-v1-1-b1c59ba7ae3b@google.com/
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#[repr(transparent)]
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#[derive(core::marker::CoercePointee)]
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pub struct ListArc<#[pointee] T, const ID: u64 = 0>
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where
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T: ListArcSafe<ID> + ?Sized,
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{
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arc: *const T,
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}
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pub trait ListArcSafe<const ID: u64> {}
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fn main() {}
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