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//! 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::{Assume, TransmuteFrom};
pub fn is_transmutable<Src, Dst>()
where
Dst: TransmuteFrom<Src, { Assume::SAFETY }>
{}
}
#[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
}
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