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//! Unless visibility is assumed, a transmutation should be rejected if the
//! destination type contains an unreachable field (e.g., a public field with a
//! private type). (This rule is distinct from type privacy, which still may
//! forbid naming such types.)
#![crate_type = "lib"]
#![feature(transmutability)]
#![allow(dead_code)]
mod assert {
use std::mem::BikeshedIntrinsicFrom;
pub fn is_transmutable<Src, Dst, Context>()
where
Dst: BikeshedIntrinsicFrom<Src, Context> // safety is NOT assumed
{}
}
mod src {
#[repr(C)] pub(in super) struct Zst;
#[repr(C)] pub(in super) struct Src {
pub(in super) field: Zst,
}
}
mod dst {
#[repr(C)] pub(in super) struct Zst;
// unreachable type
#[repr(C)] pub(self) struct Dst {
pub(in super) field: Zst,
}
}
fn test() {
struct Context;
assert::is_transmutable::<src::Src, dst::Dst, Context>();
//~^ ERROR `Dst` is private
//~| ERROR cannot be safely transmuted
}
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