| //@ 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 fn is_maybe_transmutable<Src, Dst>() |
| where |
| Dst: BikeshedIntrinsicFrom<Src, { |
| 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>(); |
| } |