Repository navigation
Anon lifetime in impl Trait no longer suggests adding a lifetime parameter #100615
Description
Activity
- added
on Aug 16, 2022 WG-prioritization assigning priority (Zulip discussion).
@rustbot label -I-prioritize +P-high
self-assigning to ensure we record a cargo-bisect to the injecting PR
I went ahead and attempted a bisection. The breadcrumbs seem to lead to rollup of #99231 with possibly #97720 being the patchset where this issue originates cc @cjgillot ?
searched nightlies: from nightly-2022-07-13 to nightly-2022-07-15
regressed nightly: nightly-2022-07-15
searched commit range: 87588a2...c2f428d
regressed commit: f1a8854bisected with cargo-bisect-rustc v0.6.3
Host triple: x86_64-unknown-linux-gnu
Reproduce with:cargo bisect-rustc --start 2022-07-13 --end 2022-07-15 --preserve
I'm not sure what would be wrong after @cjgillot change. I think this is exactly the support Camille has added. If you use
#![feature(anonymous_lifetime_in_impl_trait)]the example compiles and if you don't the error points to the anonymous lifetime and tells you that you would need the feature flag to support such case.Added an explanation in #85417 (comment).
TLDR: I proposed to allow this syntax, we made a feature gate instead, and I forgot to put back the suggestion.Reacted by Santiago Pastorino6 remaining items
Hello, I would like to work on this. So far I've been able to get this kind of output
error[E0106]: missing lifetime specifier --> test.rs:1:32 | 1 | fn foo(_: impl Iterator<Item = & u32>) {} | ^ expected named lifetime parameter | help: consider introducing a named lifetime parameter --> test.rs:1:7 | 1 | fn foo(_: impl Iterator<Item = & u32>) {} | ^with the input found in the original message.
I am looping over all generic params and checking if the full
<...>span doesn't contain thespanassociated with the parameter, at which point I try to suggest the introduction of the named lifetime parameter.I'm looking for a few pointers on:
- If my logic actually makes sense
- what other suggestions
rustc_resolve::late::lifetimes::resolve_lifetime_refshould handle. - how to properly emit the errors/suggestions (I see that late/diagnostics.rs also does similar suggestions but I'm unsure if/how I should use it)
Given
fn foo(_: impl Iterator<Item = &u32>) {}.In 1.63:
In 1.64: