From 382c964f3ea97d81f75c9716645dcedf081b4f5d Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Sat, 13 Sep 2025 00:28:46 +0200 Subject: [PATCH 1/2] small clean-up --- clippy_lints/src/lifetimes.rs | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/clippy_lints/src/lifetimes.rs b/clippy_lints/src/lifetimes.rs index 149ae5e710c1..aac5d08fd37c 100644 --- a/clippy_lints/src/lifetimes.rs +++ b/clippy_lints/src/lifetimes.rs @@ -745,7 +745,7 @@ fn report_elidable_impl_lifetimes<'tcx>( impl_: &'tcx Impl<'_>, map: &FxIndexMap>, ) { - let single_usages = map + let (elidable_lts, usages): (Vec<_>, Vec<_>) = map .iter() .filter_map(|(def_id, usages)| { if let [ @@ -762,14 +762,12 @@ fn report_elidable_impl_lifetimes<'tcx>( None } }) - .collect::>(); + .unzip(); - if single_usages.is_empty() { + if elidable_lts.is_empty() { return; } - let (elidable_lts, usages): (Vec<_>, Vec<_>) = single_usages.into_iter().unzip(); - report_elidable_lifetimes(cx, impl_.generics, &elidable_lts, &usages, true); } @@ -795,9 +793,7 @@ fn report_elidable_lifetimes( // In principle, the result of the call to `Node::ident` could be `unwrap`ped, as `DefId` should refer to a // `Node::GenericParam`. .filter_map(|&def_id| cx.tcx.hir_node_by_def_id(def_id).ident()) - .map(|ident| ident.to_string()) - .collect::>() - .join(", "); + .format(", "); let elidable_usages: Vec = usages .iter() From 25881bfc3400005b047c8eb553fb7bb2fab25950 Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Fri, 12 Sep 2025 18:56:52 +0200 Subject: [PATCH 2/2] fix(elidable_lifetime_names): avoid overlapping spans in suggestions --- clippy_lints/src/lifetimes.rs | 97 ++++++++++++---- tests/ui/crashes/ice-15666.fixed | 6 + tests/ui/crashes/ice-15666.rs | 6 + tests/ui/crashes/ice-15666.stderr | 16 +++ tests/ui/elidable_lifetime_names.fixed | 82 +++++++++++++ tests/ui/elidable_lifetime_names.rs | 82 +++++++++++++ tests/ui/elidable_lifetime_names.stderr | 146 +++++++++++++++++++++++- 7 files changed, 412 insertions(+), 23 deletions(-) create mode 100644 tests/ui/crashes/ice-15666.fixed create mode 100644 tests/ui/crashes/ice-15666.rs create mode 100644 tests/ui/crashes/ice-15666.stderr diff --git a/clippy_lints/src/lifetimes.rs b/clippy_lints/src/lifetimes.rs index aac5d08fd37c..d8b186b6787d 100644 --- a/clippy_lints/src/lifetimes.rs +++ b/clippy_lints/src/lifetimes.rs @@ -856,36 +856,89 @@ fn elision_suggestions( .filter(|param| !param.is_elided_lifetime() && !param.is_impl_trait()) .collect::>(); - let mut suggestions = if elidable_lts.len() == explicit_params.len() { + if !elidable_lts + .iter() + .all(|lt| explicit_params.iter().any(|param| param.def_id == *lt)) + { + return None; + } + + let mut suggestions = if elidable_lts.is_empty() { + vec![] + } else if elidable_lts.len() == explicit_params.len() { // if all the params are elided remove the whole generic block // // fn x<'a>() {} // ^^^^ vec![(generics.span, String::new())] } else { - elidable_lts - .iter() - .map(|&id| { - let pos = explicit_params.iter().position(|param| param.def_id == id)?; - let param = explicit_params.get(pos)?; - - let span = if let Some(next) = explicit_params.get(pos + 1) { - // fn x<'prev, 'a, 'next>() {} - // ^^^^ - param.span.until(next.span) + match &explicit_params[..] { + // no params, nothing to elide + [] => unreachable!("handled by `elidable_lts.is_empty()`"), + [param] => { + if elidable_lts.contains(¶m.def_id) { + unreachable!("handled by `elidable_lts.len() == explicit_params.len()`") } else { - // `pos` should be at least 1 here, because the param in position 0 would either have a `next` - // param or would have taken the `elidable_lts.len() == explicit_params.len()` branch. - let prev = explicit_params.get(pos - 1)?; - - // fn x<'prev, 'a>() {} - // ^^^^ - param.span.with_lo(prev.span.hi()) + unreachable!("handled by `elidable_lts.is_empty()`") + } + }, + [_, _, ..] => { + // Given a list like `<'a, 'b, 'c, 'd, ..>`, + // + // If there is a cluster of elidable lifetimes at the beginning, say `'a` and `'b`, we should + // suggest removing them _and_ the trailing comma. The span for that is `a.span.until(c.span)`: + // <'a, 'b, 'c, 'd, ..> => <'a, 'b, 'c, 'd, ..> + // ^^ ^^ ^^^^^^^^ + // + // And since we know that `'c` isn't elidable--otherwise it would've been in the cluster--we can go + // over all the lifetimes after it, and for each elidable one, add a suggestion spanning the + // lifetime itself and the comma before, because each individual suggestion is guaranteed to leave + // the list valid: + // <.., 'c, 'd, 'e, 'f, 'g, ..> => <.., 'c, 'd, 'e, 'f, 'g, ..> + // ^^ ^^ ^^ ^^^^ ^^^^^^^^ + // + // In case there is no such starting cluster, we only need to do the second part of the algorithm: + // <'a, 'b, 'c, 'd, 'e, 'f, 'g, ..> => <'a, 'b , 'c, 'd, 'e, 'f, 'g, ..> + // ^^ ^^ ^^ ^^ ^^^^^^^^^ ^^^^^^^^ + + // Split off the starting cluster + // TODO: use `slice::split_once` once stabilized (github.com/rust-lang/rust/issues/112811): + // ``` + // let Some(split) = explicit_params.split_once(|param| !elidable_lts.contains(¶m.def_id)) else { + // // there were no lifetime param that couldn't be elided + // unreachable!("handled by `elidable_lts.len() == explicit_params.len()`") + // }; + // match split { /* .. */ } + // ``` + let Some(split_pos) = explicit_params + .iter() + .position(|param| !elidable_lts.contains(¶m.def_id)) + else { + // there were no lifetime param that couldn't be elided + unreachable!("handled by `elidable_lts.len() == explicit_params.len()`") }; - - Some((span, String::new())) - }) - .collect::>>()? + let split = explicit_params + .split_at_checked(split_pos) + .expect("got `split_pos` from `position` on the same Vec"); + + match split { + ([..], []) => unreachable!("handled by `elidable_lts.len() == explicit_params.len()`"), + ([], [_]) => unreachable!("handled by `explicit_params.len() == 1`"), + (cluster, rest @ [rest_first, ..]) => { + // the span for the cluster + (cluster.first().map(|fw| fw.span.until(rest_first.span)).into_iter()) + // the span for the remaining lifetimes (calculations independent of the cluster) + .chain( + rest.array_windows() + .filter(|[_, curr]| elidable_lts.contains(&curr.def_id)) + .map(|[prev, curr]| curr.span.with_lo(prev.span.hi())), + ) + .map(|sp| (sp, String::new())) + .collect() + }, + } + }, + } }; suggestions.extend(usages.iter().map(|&usage| { diff --git a/tests/ui/crashes/ice-15666.fixed b/tests/ui/crashes/ice-15666.fixed new file mode 100644 index 000000000000..53b618765c0f --- /dev/null +++ b/tests/ui/crashes/ice-15666.fixed @@ -0,0 +1,6 @@ +#![warn(clippy::elidable_lifetime_names)] + +struct UnitVariantAccess<'a, 'b, 's>(&'a &'b &'s ()); +trait Trait<'de> {} +impl<'de> Trait<'de> for UnitVariantAccess<'_, 'de, '_> {} +//~^ elidable_lifetime_names diff --git a/tests/ui/crashes/ice-15666.rs b/tests/ui/crashes/ice-15666.rs new file mode 100644 index 000000000000..1414b3d2035e --- /dev/null +++ b/tests/ui/crashes/ice-15666.rs @@ -0,0 +1,6 @@ +#![warn(clippy::elidable_lifetime_names)] + +struct UnitVariantAccess<'a, 'b, 's>(&'a &'b &'s ()); +trait Trait<'de> {} +impl<'de, 'a, 's> Trait<'de> for UnitVariantAccess<'a, 'de, 's> {} +//~^ elidable_lifetime_names diff --git a/tests/ui/crashes/ice-15666.stderr b/tests/ui/crashes/ice-15666.stderr new file mode 100644 index 000000000000..b417c09b5c65 --- /dev/null +++ b/tests/ui/crashes/ice-15666.stderr @@ -0,0 +1,16 @@ +error: the following explicit lifetimes could be elided: 'a, 's + --> tests/ui/crashes/ice-15666.rs:5:11 + | +LL | impl<'de, 'a, 's> Trait<'de> for UnitVariantAccess<'a, 'de, 's> {} + | ^^ ^^ ^^ ^^ + | + = note: `-D clippy::elidable-lifetime-names` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::elidable_lifetime_names)]` +help: elide the lifetimes + | +LL - impl<'de, 'a, 's> Trait<'de> for UnitVariantAccess<'a, 'de, 's> {} +LL + impl<'de> Trait<'de> for UnitVariantAccess<'_, 'de, '_> {} + | + +error: aborting due to 1 previous error + diff --git a/tests/ui/elidable_lifetime_names.fixed b/tests/ui/elidable_lifetime_names.fixed index abeee5c4cef3..a6c4cb7a36a8 100644 --- a/tests/ui/elidable_lifetime_names.fixed +++ b/tests/ui/elidable_lifetime_names.fixed @@ -192,3 +192,85 @@ mod issue13923 { x.b } } + +fn issue15666_original() { + struct UnitVariantAccess<'a, 'b, 's>(&'a &'b &'s ()); + + trait Trait<'de> {} + + //~v elidable_lifetime_names + impl<'de> Trait<'de> for UnitVariantAccess<'_, 'de, '_> {} + // ^^ ^^ ^^ ^^ +} + +#[allow(clippy::upper_case_acronyms)] +fn issue15666() { + struct S1<'a>(&'a ()); + struct S2<'a, 'b>(&'a &'b ()); + struct S3<'a, 'b, 'c>(&'a &'b &'c ()); + + trait T {} + trait TA<'a> {} + trait TB<'b> {} + trait TC<'c> {} + trait TAB<'a, 'b> {} + trait TAC<'a, 'c> {} + trait TBC<'b, 'c> {} + trait TABC<'a, 'b, 'c> {} + + // 1 lifetime + + impl<'a> TA<'a> for S1<'a> {} + + //~v elidable_lifetime_names + impl T for S1<'_> {} + // ^^ + + // 2 lifetimes + + impl<'a, 'b> TAB<'a, 'b> for S2<'a, 'b> {} + + //~v elidable_lifetime_names + impl<'a> TA<'a> for S2<'a, '_> {} + // ^^ + + //~v elidable_lifetime_names + impl<'b> TB<'b> for S2<'_, 'b> {} + // ^^ + + //~v elidable_lifetime_names + impl T for S2<'_, '_> {} + // ^^ ^^ + + // 3 lifetimes + + impl<'a, 'b, 'c> TABC<'a, 'b, 'c> for S3<'a, 'b, 'c> {} + + //~v elidable_lifetime_names + impl<'a, 'b> TAB<'a, 'b> for S3<'a, 'b, '_> {} + // ^^ + + //~v elidable_lifetime_names + impl<'a, 'c> TAC<'a, 'c> for S3<'a, '_, 'c> {} + // ^^ + + //~v elidable_lifetime_names + impl<'a> TA<'a> for S3<'a, '_, '_> {} + // ^^ ^^ + + //~v elidable_lifetime_names + impl<'b, 'c> TBC<'b, 'c> for S3<'_, 'b, 'c> {} + // ^^ + + //~v elidable_lifetime_names + impl<'b> TB<'b> for S3<'_, 'b, '_> {} + // ^^ ^^ + + //~v elidable_lifetime_names + impl<'c> TC<'c> for S3<'_, '_, 'c> {} + // ^^ ^^ + + //~v elidable_lifetime_names + impl T for S3<'_, '_, '_> {} + // ^^ ^^ ^^ +} diff --git a/tests/ui/elidable_lifetime_names.rs b/tests/ui/elidable_lifetime_names.rs index fae3577a8e96..e08056b2fb56 100644 --- a/tests/ui/elidable_lifetime_names.rs +++ b/tests/ui/elidable_lifetime_names.rs @@ -192,3 +192,85 @@ mod issue13923 { x.b } } + +fn issue15666_original() { + struct UnitVariantAccess<'a, 'b, 's>(&'a &'b &'s ()); + + trait Trait<'de> {} + + //~v elidable_lifetime_names + impl<'de, 'a, 's> Trait<'de> for UnitVariantAccess<'a, 'de, 's> {} + // ^^ ^^ ^^ ^^ +} + +#[allow(clippy::upper_case_acronyms)] +fn issue15666() { + struct S1<'a>(&'a ()); + struct S2<'a, 'b>(&'a &'b ()); + struct S3<'a, 'b, 'c>(&'a &'b &'c ()); + + trait T {} + trait TA<'a> {} + trait TB<'b> {} + trait TC<'c> {} + trait TAB<'a, 'b> {} + trait TAC<'a, 'c> {} + trait TBC<'b, 'c> {} + trait TABC<'a, 'b, 'c> {} + + // 1 lifetime + + impl<'a> TA<'a> for S1<'a> {} + + //~v elidable_lifetime_names + impl<'a> T for S1<'a> {} + // ^^ + + // 2 lifetimes + + impl<'a, 'b> TAB<'a, 'b> for S2<'a, 'b> {} + + //~v elidable_lifetime_names + impl<'a, 'b> TA<'a> for S2<'a, 'b> {} + // ^^ + + //~v elidable_lifetime_names + impl<'a, 'b> TB<'b> for S2<'a, 'b> {} + // ^^ + + //~v elidable_lifetime_names + impl<'a, 'b> T for S2<'a, 'b> {} + // ^^ ^^ + + // 3 lifetimes + + impl<'a, 'b, 'c> TABC<'a, 'b, 'c> for S3<'a, 'b, 'c> {} + + //~v elidable_lifetime_names + impl<'a, 'b, 'c> TAB<'a, 'b> for S3<'a, 'b, 'c> {} + // ^^ + + //~v elidable_lifetime_names + impl<'a, 'b, 'c> TAC<'a, 'c> for S3<'a, 'b, 'c> {} + // ^^ + + //~v elidable_lifetime_names + impl<'a, 'b, 'c> TA<'a> for S3<'a, 'b, 'c> {} + // ^^ ^^ + + //~v elidable_lifetime_names + impl<'a, 'b, 'c> TBC<'b, 'c> for S3<'a, 'b, 'c> {} + // ^^ + + //~v elidable_lifetime_names + impl<'a, 'b, 'c> TB<'b> for S3<'a, 'b, 'c> {} + // ^^ ^^ + + //~v elidable_lifetime_names + impl<'a, 'b, 'c> TC<'c> for S3<'a, 'b, 'c> {} + // ^^ ^^ + + //~v elidable_lifetime_names + impl<'a, 'b, 'c> T for S3<'a, 'b, 'c> {} + // ^^ ^^ ^^ +} diff --git a/tests/ui/elidable_lifetime_names.stderr b/tests/ui/elidable_lifetime_names.stderr index a60dfc697564..03fe383b8f67 100644 --- a/tests/ui/elidable_lifetime_names.stderr +++ b/tests/ui/elidable_lifetime_names.stderr @@ -158,5 +158,149 @@ LL | o: &'t str, LL ~ ) -> Content<'t, '_> { | -error: aborting due to 12 previous errors +error: the following explicit lifetimes could be elided: 'a, 's + --> tests/ui/elidable_lifetime_names.rs:202:15 + | +LL | impl<'de, 'a, 's> Trait<'de> for UnitVariantAccess<'a, 'de, 's> {} + | ^^ ^^ ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'de, 'a, 's> Trait<'de> for UnitVariantAccess<'a, 'de, 's> {} +LL + impl<'de> Trait<'de> for UnitVariantAccess<'_, 'de, '_> {} + | + +error: the following explicit lifetimes could be elided: 'a + --> tests/ui/elidable_lifetime_names.rs:226:10 + | +LL | impl<'a> T for S1<'a> {} + | ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a> T for S1<'a> {} +LL + impl T for S1<'_> {} + | + +error: the following explicit lifetimes could be elided: 'b + --> tests/ui/elidable_lifetime_names.rs:234:14 + | +LL | impl<'a, 'b> TA<'a> for S2<'a, 'b> {} + | ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b> TA<'a> for S2<'a, 'b> {} +LL + impl<'a> TA<'a> for S2<'a, '_> {} + | + +error: the following explicit lifetimes could be elided: 'a + --> tests/ui/elidable_lifetime_names.rs:238:10 + | +LL | impl<'a, 'b> TB<'b> for S2<'a, 'b> {} + | ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b> TB<'b> for S2<'a, 'b> {} +LL + impl<'b> TB<'b> for S2<'_, 'b> {} + | + +error: the following explicit lifetimes could be elided: 'a, 'b + --> tests/ui/elidable_lifetime_names.rs:242:10 + | +LL | impl<'a, 'b> T for S2<'a, 'b> {} + | ^^ ^^ ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b> T for S2<'a, 'b> {} +LL + impl T for S2<'_, '_> {} + | + +error: the following explicit lifetimes could be elided: 'c + --> tests/ui/elidable_lifetime_names.rs:250:18 + | +LL | impl<'a, 'b, 'c> TAB<'a, 'b> for S3<'a, 'b, 'c> {} + | ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b, 'c> TAB<'a, 'b> for S3<'a, 'b, 'c> {} +LL + impl<'a, 'b> TAB<'a, 'b> for S3<'a, 'b, '_> {} + | + +error: the following explicit lifetimes could be elided: 'b + --> tests/ui/elidable_lifetime_names.rs:254:14 + | +LL | impl<'a, 'b, 'c> TAC<'a, 'c> for S3<'a, 'b, 'c> {} + | ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b, 'c> TAC<'a, 'c> for S3<'a, 'b, 'c> {} +LL + impl<'a, 'c> TAC<'a, 'c> for S3<'a, '_, 'c> {} + | + +error: the following explicit lifetimes could be elided: 'b, 'c + --> tests/ui/elidable_lifetime_names.rs:258:14 + | +LL | impl<'a, 'b, 'c> TA<'a> for S3<'a, 'b, 'c> {} + | ^^ ^^ ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b, 'c> TA<'a> for S3<'a, 'b, 'c> {} +LL + impl<'a> TA<'a> for S3<'a, '_, '_> {} + | + +error: the following explicit lifetimes could be elided: 'a + --> tests/ui/elidable_lifetime_names.rs:262:10 + | +LL | impl<'a, 'b, 'c> TBC<'b, 'c> for S3<'a, 'b, 'c> {} + | ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b, 'c> TBC<'b, 'c> for S3<'a, 'b, 'c> {} +LL + impl<'b, 'c> TBC<'b, 'c> for S3<'_, 'b, 'c> {} + | + +error: the following explicit lifetimes could be elided: 'a, 'c + --> tests/ui/elidable_lifetime_names.rs:266:10 + | +LL | impl<'a, 'b, 'c> TB<'b> for S3<'a, 'b, 'c> {} + | ^^ ^^ ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b, 'c> TB<'b> for S3<'a, 'b, 'c> {} +LL + impl<'b> TB<'b> for S3<'_, 'b, '_> {} + | + +error: the following explicit lifetimes could be elided: 'a, 'b + --> tests/ui/elidable_lifetime_names.rs:270:10 + | +LL | impl<'a, 'b, 'c> TC<'c> for S3<'a, 'b, 'c> {} + | ^^ ^^ ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b, 'c> TC<'c> for S3<'a, 'b, 'c> {} +LL + impl<'c> TC<'c> for S3<'_, '_, 'c> {} + | + +error: the following explicit lifetimes could be elided: 'a, 'b, 'c + --> tests/ui/elidable_lifetime_names.rs:274:10 + | +LL | impl<'a, 'b, 'c> T for S3<'a, 'b, 'c> {} + | ^^ ^^ ^^ ^^ ^^ ^^ + | +help: elide the lifetimes + | +LL - impl<'a, 'b, 'c> T for S3<'a, 'b, 'c> {} +LL + impl T for S3<'_, '_, '_> {} + | + +error: aborting due to 24 previous errors