#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(transmutability)]
use core::mem::{Assume, TransmuteFrom};
struct EvenU8 {
    val: u8,
}
fn main() {
    let src: u8 = 42;
    let maybe_dst: Option<EvenU8> = if src % 2 == 0 {
        Some(unsafe { <_ as TransmuteFrom<_, { Assume::SAFETY }>>::transmute(src) })
    } else {
        None
    };
    assert!(matches!(maybe_dst, Some(EvenU8 { val : 42 })));
}