An (experimental) RFC repo devoted to Rust's impl Trait.
This repo is an effort to collect and organize the discussion around
future impl Trait RFCs.
impl Trait allows functions to leave their return types "abstract."
Abstract return types allow a function to hide a concrete return type behind a
trait interface similar to trait objects, while still generating the same
statically-dispatched code as with concrete types.
The initial conservative proposal for impl Trait was accepted as
RFC 1522 - Conservative impl Trait.
This proposal was expanded upon in
RFC 1951 - Expand impl Trait,
which settled the impl Trait syntax design, resolved questions around type
and lifetime parameter scopes, and added impl Trait to argument position.
However, there are still more features left to be added before the impl Trait
story can be considered complete. This repo aims to track information and
discussion of these additional features, and to address them through a followup
RFC (possibly multiple).
The help-wanted label
indicates issues where a PR would be most welcome.
- P-essential means that we have to resolve this.
- P-nice-to-have means that it might be nice to include this feature.
- P-wild-and-crazy means that theses are far-out ideas that may or may not make sense.
Once an issue is closed, it ought to have a resolution tag.
Z-updated-rfc-- text was added to the RFC resolving this questionZ-open-question-- text was added to the RFC making this an "open question" to be resolved before stabilizationZ-alternative-- text was added to the RFC describing this as an alternative but not endorsing itZ-no-go-- nothing was added to the RFC. This is out of scope or just something we decided against.Z-duplicate-- a duplicate of some other issue