// check-pass #![stable(feature = "core", since = "1.6.0")] #![feature(staged_api)] #![feature(const_precise_live_drops)] enum Either { Left(T), Right(S), } impl Either { #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_unstable(feature = "foo", issue = "none")] pub const fn unwrap(self) -> T { match self { Self::Left(t) => t, Self::Right(t) => t, } } } fn main() {}