#[may_dangle] compiles on non-Drop impls

[Ixrec]

The RFC pretty strongly implies that this attribute is only supposed to be used on Drop, and the semantics of it don't make any sense on other traits. Yet, this compiles:

#![feature(dropck_eyepatch)]

struct Foo<T>(T);

unsafe impl<#[may_dangle] T> std::ops::Deref for Foo<T> {
    type Target = T;
    fn deref(&self) -> &T {
        &self.0
    }
}

playground link

[oli-obk]

see also https://github.com/rust-lang/rust/pull/128444/files for how the attribute just works on anything like functions, imports, ...

[kei519]

@rustbot claim

[kei519]

This seems to be fixed with 3a9bf4551374893fdc522572ee569028186e22cc.

[jieyouxu]

Fixed by #129235