//@ revisions: e2021 e2024 //@[e2021] edition: 2021 //@[e2021] run-rustfix //@[e2024] edition: 2024 //@[e2024] compile-flags: -Zunstable-options //@[e2024] check-pass #![deny(rust_2024_prelude_collisions)] trait Meow { fn into_future(&self) {} } impl Meow for Cat {} struct Cat; impl core::future::IntoFuture for Cat { type Output = (); type IntoFuture = core::future::Ready<()>; fn into_future(self) -> Self::IntoFuture { core::future::ready(()) } } fn main() { Meow::into_future(&Cat); //[e2021]~^ ERROR trait method `into_future` will become ambiguous in Rust 2024 //[e2021]~| WARN this is accepted in the current edition (Rust 2021) but is a hard error in Rust 2024! }