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// check-pass
//! The fields of a struct should be laid out in lexical order.
#![crate_type = "lib"]
#![feature(transmutability)]
#![allow(dead_code)]
mod assert {
use std::mem::{Assume, BikeshedIntrinsicFrom};
pub struct Context;
pub fn is_transmutable<Src, Dst>()
where
Dst: BikeshedIntrinsicFrom<Src, Context, {
Assume::ALIGNMENT
.and(Assume::LIFETIMES)
.and(Assume::SAFETY)
.and(Assume::VALIDITY)
}>
{}
}
#[repr(u8)] enum V0 { V = 0 }
#[repr(u8)] enum V1 { V = 1 }
#[repr(u8)] enum V2 { V = 2 }
#[repr(C)] struct S01(V0, V1);
#[repr(C)] struct S012(V0, V1, V2);
fn should_order_tag_and_fields_correctly() {
// An implementation that (incorrectly) arranges S01 as [0x01, 0x00] will,
// in principle, reject this transmutation.
assert::is_transmutable::<S01, V0>();
// Again, but with one more field.
assert::is_transmutable::<S012, S01>();
}
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