#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(transmutability)]
use core::mem::{Assume, TransmuteFrom};
fn main() {
    let src: u8 = 1;
    let maybe_dst: Option<bool> = if src == 0 || src == 1 {
        Some(unsafe { <_ as TransmuteFrom<_, { Assume::VALIDITY }>>::transmute(src) })
    } else {
        None
    };
    assert_eq!(maybe_dst, Some(true));
}