diff options
Diffstat (limited to 'src/test/ui/transmutability/unions/should_reject_contraction.rs')
-rw-r--r-- | src/test/ui/transmutability/unions/should_reject_contraction.rs | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/test/ui/transmutability/unions/should_reject_contraction.rs b/src/test/ui/transmutability/unions/should_reject_contraction.rs new file mode 100644 index 000000000..e8138d0e0 --- /dev/null +++ b/src/test/ui/transmutability/unions/should_reject_contraction.rs @@ -0,0 +1,36 @@ +//! Validity may not be contracted, unless validity is assumed. + +#![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_transmutable<Src, Dst>() + where + Dst: BikeshedIntrinsicFrom<Src, Context, false, false, false, true> + {} +} + +#[derive(Clone, Copy)] #[repr(u8)] enum Ox00 { V = 0x00 } +#[derive(Clone, Copy)] #[repr(u8)] enum Ox01 { V = 0x01 } +#[derive(Clone, Copy)] #[repr(u8)] enum OxFF { V = 0xFF } + +fn test() { + #[repr(C)] + union Subset { + a: Ox00, + b: OxFF, + } + + #[repr(C)] + union Superset { + a: Ox00, + b: OxFF, + c: Ox01, + } + + assert::is_transmutable::<Superset, Subset>(); //~ ERROR cannot be safely transmuted +} |