135 lines
3.7 KiB
Rust
135 lines
3.7 KiB
Rust
#![feature(derive_coerce_pointee, arbitrary_self_types)]
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extern crate core;
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use std::marker::CoercePointee;
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#[derive(CoercePointee)]
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//~^ ERROR: `CoercePointee` can only be derived on `struct`s with `#[repr(transparent)]`
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enum NotStruct<'a, T: ?Sized> {
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Variant(&'a T),
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}
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#[derive(CoercePointee)]
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//~^ ERROR: `CoercePointee` can only be derived on `struct`s with at least one field
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#[repr(transparent)]
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struct NoField<'a, #[pointee] T: ?Sized> {}
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//~^ ERROR: lifetime parameter `'a` is never used
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//~| ERROR: type parameter `T` is never used
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#[derive(CoercePointee)]
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//~^ ERROR: `CoercePointee` can only be derived on `struct`s with at least one field
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#[repr(transparent)]
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struct NoFieldUnit<'a, #[pointee] T: ?Sized>();
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//~^ ERROR: lifetime parameter `'a` is never used
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//~| ERROR: type parameter `T` is never used
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#[derive(CoercePointee)]
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//~^ ERROR: `CoercePointee` can only be derived on `struct`s that are generic over at least one type
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#[repr(transparent)]
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struct NoGeneric<'a>(&'a u8);
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#[derive(CoercePointee)]
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//~^ ERROR: exactly one generic type parameter must be marked as #[pointee] to derive CoercePointee traits
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#[repr(transparent)]
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struct AmbiguousPointee<'a, T1: ?Sized, T2: ?Sized> {
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a: (&'a T1, &'a T2),
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct TooManyPointees<'a, #[pointee] A: ?Sized, #[pointee] B: ?Sized>((&'a A, &'a B));
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//~^ ERROR: only one type parameter can be marked as `#[pointee]` when deriving CoercePointee traits
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#[derive(CoercePointee)]
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//~^ ERROR: `CoercePointee` can only be derived on `struct`s with `#[repr(transparent)]`
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struct NotTransparent<'a, #[pointee] T: ?Sized> {
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct NoMaybeSized<'a, #[pointee] T> {
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//~^ ERROR: `derive(CoercePointee)` requires T to be marked `?Sized`
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct PointeeOnField<'a, #[pointee] T: ?Sized> {
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#[pointee]
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//~^ ERROR: the `#[pointee]` attribute may only be used on generic parameters
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct PointeeInTypeConstBlock<
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'a,
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T: ?Sized = [u32; const {
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struct UhOh<#[pointee] T>(T);
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//~^ ERROR: the `#[pointee]` attribute may only be used on generic parameters
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10
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}],
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> {
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct PointeeInConstConstBlock<
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'a,
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T: ?Sized,
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const V: u32 = {
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struct UhOh<#[pointee] T>(T);
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//~^ ERROR: the `#[pointee]` attribute may only be used on generic parameters
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10
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},
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> {
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct PointeeInAnotherTypeConstBlock<'a, #[pointee] T: ?Sized> {
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ptr: PointeeInConstConstBlock<
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'a,
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T,
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{
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struct UhOh<#[pointee] T>(T);
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//~^ ERROR: the `#[pointee]` attribute may only be used on generic parameters
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0
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},
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>,
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}
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// However, reordering attributes should work nevertheless.
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#[repr(transparent)]
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#[derive(CoercePointee)]
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struct ThisIsAPossibleCoercePointee<'a, #[pointee] T: ?Sized> {
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ptr: &'a T,
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}
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// Also, these paths to Sized should work
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct StdSized<'a, #[pointee] T: ?std::marker::Sized> {
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct CoreSized<'a, #[pointee] T: ?core::marker::Sized> {
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct GlobalStdSized<'a, #[pointee] T: ?::std::marker::Sized> {
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ptr: &'a T,
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}
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#[derive(CoercePointee)]
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#[repr(transparent)]
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struct GlobalCoreSized<'a, #[pointee] T: ?::core::marker::Sized> {
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ptr: &'a T,
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}
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fn main() {}
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