diff options
| -rw-r--r-- | compiler/rustc_lint/src/impl_trait_overcaptures.rs | 223 |
1 files changed, 113 insertions, 110 deletions
diff --git a/compiler/rustc_lint/src/impl_trait_overcaptures.rs b/compiler/rustc_lint/src/impl_trait_overcaptures.rs index 42c800a81af..98330792673 100644 --- a/compiler/rustc_lint/src/impl_trait_overcaptures.rs +++ b/compiler/rustc_lint/src/impl_trait_overcaptures.rs @@ -264,130 +264,133 @@ where && let hir::OpaqueTyOrigin::FnReturn(parent_def_id) = opaque.origin && parent_def_id == self.parent_def_id { - // Compute the set of args that are captured by the opaque... - let mut captured = FxIndexSet::default(); - let mut captured_regions = FxIndexSet::default(); - let variances = self.tcx.variances_of(opaque_def_id); - let mut current_def_id = Some(opaque_def_id.to_def_id()); - while let Some(def_id) = current_def_id { - let generics = self.tcx.generics_of(def_id); - for param in &generics.own_params { - // A param is captured if it's invariant. - if variances[param.index as usize] != ty::Invariant { - continue; - } - - let arg = opaque_ty.args[param.index as usize]; - // We need to turn all `ty::Param`/`ConstKind::Param` and - // `ReEarlyParam`/`ReBound` into def ids. - captured.insert(extract_def_id_from_arg(self.tcx, generics, arg)); - - captured_regions.extend(arg.as_region()); - } - current_def_id = generics.parent; - } - - // Compute the set of in scope params that are not captured. Get their spans, - // since that's all we really care about them for emitting the diagnostic. - let mut uncaptured_args: FxIndexSet<_> = self - .in_scope_parameters - .iter() - .filter(|&(def_id, _)| !captured.contains(def_id)) - .collect(); - - // These are args that we know are likely fine to "overcapture", since they can be - // contravariantly shortened to one of the already-captured lifetimes that they - // outlive. - let covariant_long_args: FxIndexSet<_> = uncaptured_args - .iter() - .copied() - .filter(|&(def_id, kind)| { - let Some(ty::Bivariant | ty::Contravariant) = self.variances.get(def_id) else { - return false; - }; - let DefKind::LifetimeParam = self.tcx.def_kind(def_id) else { - return false; - }; - let uncaptured = match *kind { - ParamKind::Early(name, index) => ty::Region::new_early_param( - self.tcx, - ty::EarlyParamRegion { name, index }, - ), - ParamKind::Free(def_id, name) => ty::Region::new_late_param( - self.tcx, - self.parent_def_id.to_def_id(), - ty::BoundRegionKind::BrNamed(def_id, name), - ), - ParamKind::Late => return false, - }; - // Does this region outlive any captured region? - captured_regions.iter().any(|r| { - self.outlives_env - .free_region_map() - .sub_free_regions(self.tcx, *r, uncaptured) - }) - }) - .collect(); - // 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() { - 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); - // Take all lifetime params first, then all others (ty/ct). - let generics: Vec<_> = lifetimes - .into_iter() - .chain(others) - .map(|def_id| self.tcx.item_name(def_id).to_string()) - .collect(); - // Make sure that we're not trying to name any APITs - if generics.iter().all(|name| !name.starts_with("impl ")) { - Some(( - format!(" + use<{}>", generics.join(", ")), - opaque_span.shrink_to_hi(), - )) - } else { - None + // Compute the set of args that are captured by the opaque... + let mut captured = FxIndexSet::default(); + let mut captured_regions = FxIndexSet::default(); + let variances = self.tcx.variances_of(opaque_def_id); + let mut current_def_id = Some(opaque_def_id.to_def_id()); + while let Some(def_id) = current_def_id { + let generics = self.tcx.generics_of(def_id); + for param in &generics.own_params { + // A param is captured if it's invariant. + if variances[param.index as usize] != ty::Invariant { + continue; + } + + let arg = opaque_ty.args[param.index as usize]; + // We need to turn all `ty::Param`/`ConstKind::Param` and + // `ReEarlyParam`/`ReBound` into def ids. + captured.insert(extract_def_id_from_arg(self.tcx, generics, arg)); + + captured_regions.extend(arg.as_region()); } - } else { - None - }; + current_def_id = generics.parent; + } + + // Compute the set of in scope params that are not captured. Get their spans, + // since that's all we really care about them for emitting the diagnostic. + let mut uncaptured_args: FxIndexSet<_> = self + .in_scope_parameters + .iter() + .filter(|&(def_id, _)| !captured.contains(def_id)) + .collect(); - let uncaptured_spans: Vec<_> = uncaptured_args - .into_iter() - .map(|(def_id, _)| self.tcx.def_span(def_id)) + // These are args that we know are likely fine to "overcapture", since they can be + // contravariantly shortened to one of the already-captured lifetimes that they + // outlive. + let covariant_long_args: FxIndexSet<_> = uncaptured_args + .iter() + .copied() + .filter(|&(def_id, kind)| { + let Some(ty::Bivariant | ty::Contravariant) = self.variances.get(def_id) + else { + return false; + }; + let DefKind::LifetimeParam = self.tcx.def_kind(def_id) else { + return false; + }; + let uncaptured = match *kind { + ParamKind::Early(name, index) => ty::Region::new_early_param( + self.tcx, + ty::EarlyParamRegion { name, index }, + ), + ParamKind::Free(def_id, name) => ty::Region::new_late_param( + self.tcx, + self.parent_def_id.to_def_id(), + ty::BoundRegionKind::BrNamed(def_id, name), + ), + ParamKind::Late => return false, + }; + // Does this region outlive any captured region? + captured_regions.iter().any(|r| { + self.outlives_env + .free_region_map() + .sub_free_regions(self.tcx, *r, uncaptured) + }) + }) .collect(); + // We don't care to warn on these args. + uncaptured_args.retain(|arg| !covariant_long_args.contains(arg)); + + // 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 !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 + }); + // Take all lifetime params first, then all others (ty/ct). + let generics: Vec<_> = lifetimes + .into_iter() + .chain(others) + .map(|def_id| self.tcx.item_name(def_id).to_string()) + .collect(); + // Make sure that we're not trying to name any APITs + if generics.iter().all(|name| !name.starts_with("impl ")) { + Some(( + format!(" + use<{}>", generics.join(", ")), + opaque_span.shrink_to_hi(), + )) + } else { + None + } + } else { + None + }; - self.tcx.emit_node_span_lint( - IMPL_TRAIT_OVERCAPTURES, - self.tcx.local_def_id_to_hir_id(opaque_def_id), - opaque_span, - ImplTraitOvercapturesLint { - self_ty: t, - num_captured: uncaptured_spans.len(), - uncaptured_spans, - suggestion, - }, - ); + let uncaptured_spans: Vec<_> = uncaptured_args + .into_iter() + .map(|(def_id, _)| self.tcx.def_span(def_id)) + .collect(); + + self.tcx.emit_node_span_lint( + IMPL_TRAIT_OVERCAPTURES, + self.tcx.local_def_id_to_hir_id(opaque_def_id), + opaque_span, + ImplTraitOvercapturesLint { + self_ty: t, + num_captured: uncaptured_spans.len(), + uncaptured_spans, + suggestion, + }, + ); + } } + // 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)), |