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Do less work on the good path

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This commit is contained in:
Michael Goulet 2024-08-12 18:05:07 -04:00
parent f8f4d50aa3
commit 70641356dc
1 changed files with 114 additions and 111 deletions
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29
compiler/rustc_lint/src/impl_trait_overcaptures.rs
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@ -263,6 +263,12 @@ fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
self.tcx.hir_node_by_def_id(opaque_def_id).expect_item().expect_opaque_ty()
&& let hir::OpaqueTyOrigin::FnReturn(parent_def_id) = opaque.origin
&& parent_def_id == self.parent_def_id
{
let opaque_span = self.tcx.def_span(opaque_def_id);
let new_capture_rules =
opaque_span.at_least_rust_2024() || self.tcx.features().lifetime_capture_rules_2024;
if !new_capture_rules
&& !opaque.bounds.iter().any(|bound| matches!(bound, hir::GenericBound::Use(..)))
{
// Compute the set of args that are captured by the opaque...
let mut captured = FxIndexSet::default();
@ -302,7 +308,8 @@ fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
.iter()
.copied()
.filter(|&(def_id, kind)| {
let Some(ty::Bivariant | ty::Contravariant) = self.variances.get(def_id) else {
let Some(ty::Bivariant | ty::Contravariant) = self.variances.get(def_id)
else {
return false;
};
let DefKind::LifetimeParam = self.tcx.def_kind(def_id) else {
@ -331,23 +338,17 @@ fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
// We don't care to warn on these args.
uncaptured_args.retain(|arg| !covariant_long_args.contains(arg));
let opaque_span = self.tcx.def_span(opaque_def_id);
let new_capture_rules =
opaque_span.at_least_rust_2024() || self.tcx.features().lifetime_capture_rules_2024;
// If we have uncaptured args, and if the opaque doesn't already have
// `use<>` syntax on it, and we're < edition 2024, then warn the user.
if !new_capture_rules
&& !opaque.bounds.iter().any(|bound| matches!(bound, hir::GenericBound::Use(..)))
&& !uncaptured_args.is_empty()
{
if !uncaptured_args.is_empty() {
let suggestion = if let Ok(snippet) =
self.tcx.sess.source_map().span_to_snippet(opaque_span)
&& snippet.starts_with("impl ")
{
let (lifetimes, others): (Vec<_>, Vec<_>) = captured
.into_iter()
.partition(|def_id| self.tcx.def_kind(*def_id) == DefKind::LifetimeParam);
let (lifetimes, others): (Vec<_>, Vec<_>) =
captured.into_iter().partition(|def_id| {
self.tcx.def_kind(*def_id) == DefKind::LifetimeParam
});
// Take all lifetime params first, then all others (ty/ct).
let generics: Vec<_> = lifetimes
.into_iter()
@ -384,10 +385,12 @@ fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
},
);
}
}
// Otherwise, if we are edition 2024, have `use<>` syntax, and
// have no uncaptured args, then we should warn to the user that
// it's redundant to capture all args explicitly.
else if new_capture_rules
if new_capture_rules
&& let Some((captured_args, capturing_span)) =
opaque.bounds.iter().find_map(|bound| match *bound {
hir::GenericBound::Use(a, s) => Some((a, s)),