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Diffstat (limited to '')
-rw-r--r-- | src/test/ui/transmutability/unions/repr/should_handle_align.rs | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/src/test/ui/transmutability/unions/repr/should_handle_align.rs b/src/test/ui/transmutability/unions/repr/should_handle_align.rs new file mode 100644 index 000000000..e215799a2 --- /dev/null +++ b/src/test/ui/transmutability/unions/repr/should_handle_align.rs @@ -0,0 +1,40 @@ +// 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::BikeshedIntrinsicFrom; + pub struct Context; + + pub fn is_maybe_transmutable<Src, Dst>() + where + Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, 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>(); +} |