Syntax for precise capturing: impl Trait + use<..> · Issue #125836 · rust-lang/rust (original) (raw)

For precise capturing (#123432), we need to decide which syntax to adopt.

The original two, left as an open question in the RFC, were:

1. impl use<..> Trait
   • This syntax is used throughout the RFC.
2. use<..> impl Trait
   • This syntax is the worthy challenger.

(See the alternatives section in the RFC for a detailed comparative analysis of these options. In particular, so as to reduce duplication, please read that section carefully before commenting here.)

However, in the design meeting on 2024-06-05, as described below, we settled on placing use<..> within the list of bounds, e.g.:

fn foo<'a>() -> impl Sized + use<'a> {}

This issue is to track the resolution of the open question on syntax left in the RFC.

Tracking:

• Tracking issue for precise_capturing syntax #123432