This is a tracking issue for the RFC "Refined trait implementations" (rust-lang/rfcs#3245).
The feature gate for the issue is #![feature(refine)].

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

• Implement the RFC (cc @rust-lang/compiler -- can anyone write up mentoring
  instructions?)
• Adjust documentation (see instructions on rustc-dev-guide)
• Stabilization PR (see instructions on rustc-dev-guide)

Unresolved Questions

• Should #[refine] be required in future editions? Options:
  • Required
  • Recommended (by a lint that can be disabled on refined impls without a #[refine])
  • Not recommended (refined APIs are available without the attribute)

See the RFC for more information.

Implementation history