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// check-pass
//! The presence of an `align(X)` annotation must be accounted for.
#![crate_type = "lib"]
#![feature(transmutability)]
#![allow(dead_code, incomplete_features, non_camel_case_types)]
mod assert {
use std::mem::{Assume, BikeshedIntrinsicFrom};
pub struct Context;
pub fn is_maybe_transmutable<Src, Dst>()
where
Dst: BikeshedIntrinsicFrom<Src, Context, {
Assume {
alignment: true,
lifetimes: true,
safety: true,
validity: true,
}
}>
{}
}
fn should_pad_explicitly_aligned_field() {
#[derive(Clone, Copy)] #[repr(u8)] enum V0u8 { V = 0 }
#[derive(Clone, Copy)] #[repr(u8)] enum V1u8 { V = 1 }
#[repr(C)]
pub union Uninit {
a: (),
b: V1u8,
}
#[repr(C, align(2))]
pub union align_2 {
a: V0u8,
}
#[repr(C)] struct ImplicitlyPadded(align_2, V0u8);
#[repr(C)] struct ExplicitlyPadded(V0u8, Uninit, V0u8);
// An implementation that (incorrectly) does not place a padding byte after
// `align_2` will, incorrectly, reject the following transmutations.
assert::is_maybe_transmutable::<ImplicitlyPadded, ExplicitlyPadded>();
assert::is_maybe_transmutable::<ExplicitlyPadded, ImplicitlyPadded>();
}
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