[perf] proc-macro Ident should have method as_str

[loynoir]

According to https://doc.rust-lang.org/proc_macro/struct.Ident.html

There are

• pub fn new(string: &str, span: Span) -> Ident

• ident.to_string()

Should provide below for performance

• ident.as_str()

Very common actual usage

ident_string = ident.to_string()

match ident_string.as_str() { ... }

Expect usage

match ident.as_str() { ... }

[jieyouxu]

cc @m-ou-se, maybe this issue should be an ACP aginst https://github.com/rust-lang/libs-team/issues instead?

[jieyouxu]

The rust-lang/rust issue tracker is not suited to handle standard library (API) feature requests. Please consult The feature lifecycle — Standard library developers Guide for advice on (proposals to) adding new standard library features. If you have a concrete proposal, you should instead submit an API Change Proposal (ACP) against the rust-lang/libs-team repository.

You could also discuss your proposal on the #t-libs zulip channel by opening a new topic, and/or discuss your proposal on the Rust Internals forum.