#![cfg(feature = "blanket_impl")] #![feature(never_type)] use unwrap_infallible::UnwrapInfallible; enum MyNeverToken {} impl From for ! { fn from(never: MyNeverToken) -> Self { match never {} } } #[test] fn with_custom_type() { let r: Result = Ok(true); assert!(r.unwrap_infallible()); }