Parse precise capturing syntax

[dtolnay]

RFC: rust-lang/rfcs#3617
Tracking issue: rust-lang/rust#123432

fn f<'a, T>() -> impl Sized + use<'a, T> {}

[traviscross]

Just an update here that the stabilization report for this has gone up.

The earliest this syntax could conceivably stabilize is with Rust 1.82, which will branch on 2024-08-30 and will be released on 2024-10-17.