Add "impl PartialEq<&str> for Ident"

[CreepySkeleton]

Currently there's only one way to examine contents of an Ident - &*ident.to_string() == "foo". I'd say this is kind of cumbersome and the more direct approach would be useful - ident == "foo".

By the way, I had encountered some people from the core team claim it's not safe to expose an a str reference from Ident - I don't know why and I would really love to be given an explanation. But keeping this in mind, still, proposed impl doesn't expose anything so it's should be safe anyway.

[CreepySkeleton]

Probably we could use impl PartialEq<&str> for LitStr too

[dtolnay]

This impl already exists. Playground

[CreepySkeleton]

Oooh... now I'm really curious why my code wasn't working. So what about AsStr for Ident? People just keep saying "no way, use to_string()` but nobody can explain why

[dtolnay]

Idents are stored in a thread local interner -- rust-lang/rust#38356. That's why they are not Send. Exposing a conversion from &'a Ident to &'a str would be unsound because you could do Box::leak(Box::new(ident)) to get a &'static Ident, convert to &'static str, hand it across to a different thread, have the original thread die and clear the interner, and then the &str continuing to exist would be undefined behavior.

[CreepySkeleton]

@dtolnay Thank's for clarification, I believe this issue should be closed