diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:03:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:03:36 +0000 |
commit | 17d40c6057c88f4c432b0d7bac88e1b84cb7e67f (patch) | |
tree | 3f66c4a5918660bb8a758ab6cda5ff8ee4f6cdcd /compiler/rustc_resolve/src/late/lifetimes.rs | |
parent | Adding upstream version 1.64.0+dfsg1. (diff) | |
download | rustc-f7f0cc2a5d72e2c61c1f6900e70eec992bea4273.tar.xz rustc-f7f0cc2a5d72e2c61c1f6900e70eec992bea4273.zip |
Adding upstream version 1.65.0+dfsg1.upstream/1.65.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_resolve/src/late/lifetimes.rs | 511 |
1 files changed, 111 insertions, 400 deletions
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs index 94460e33d..4d9704617 100644 --- a/compiler/rustc_resolve/src/late/lifetimes.rs +++ b/compiler/rustc_resolve/src/late/lifetimes.rs @@ -11,23 +11,21 @@ use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet}; use rustc_errors::struct_span_err; use rustc_hir as hir; use rustc_hir::def::{DefKind, Res}; -use rustc_hir::def_id::{DefIdMap, LocalDefId}; +use rustc_hir::def_id::LocalDefId; use rustc_hir::intravisit::{self, Visitor}; use rustc_hir::{GenericArg, GenericParam, GenericParamKind, HirIdMap, LifetimeName, Node}; use rustc_middle::bug; use rustc_middle::hir::map::Map; use rustc_middle::hir::nested_filter; use rustc_middle::middle::resolve_lifetime::*; -use rustc_middle::ty::{self, GenericParamDefKind, TyCtxt}; +use rustc_middle::ty::{self, DefIdTree, TyCtxt}; use rustc_span::def_id::DefId; use rustc_span::symbol::{sym, Ident}; use rustc_span::Span; -use std::borrow::Cow; use std::fmt; -use std::mem::take; trait RegionExt { - fn early(hir_map: Map<'_>, index: &mut u32, param: &GenericParam<'_>) -> (LocalDefId, Region); + fn early(hir_map: Map<'_>, param: &GenericParam<'_>) -> (LocalDefId, Region); fn late(index: u32, hir_map: Map<'_>, param: &GenericParam<'_>) -> (LocalDefId, Region); @@ -36,19 +34,13 @@ trait RegionExt { fn shifted(self, amount: u32) -> Region; fn shifted_out_to_binder(self, binder: ty::DebruijnIndex) -> Region; - - fn subst<'a, L>(self, params: L, map: &NamedRegionMap) -> Option<Region> - where - L: Iterator<Item = &'a hir::Lifetime>; } impl RegionExt for Region { - fn early(hir_map: Map<'_>, index: &mut u32, param: &GenericParam<'_>) -> (LocalDefId, Region) { - let i = *index; - *index += 1; + fn early(hir_map: Map<'_>, param: &GenericParam<'_>) -> (LocalDefId, Region) { let def_id = hir_map.local_def_id(param.hir_id); - debug!("Region::early: index={} def_id={:?}", i, def_id); - (def_id, Region::EarlyBound(i, def_id.to_def_id())) + debug!("Region::early: def_id={:?}", def_id); + (def_id, Region::EarlyBound(def_id.to_def_id())) } fn late(idx: u32, hir_map: Map<'_>, param: &GenericParam<'_>) -> (LocalDefId, Region) { @@ -65,9 +57,7 @@ impl RegionExt for Region { match *self { Region::Static => None, - Region::EarlyBound(_, id) | Region::LateBound(_, _, id) | Region::Free(_, id) => { - Some(id) - } + Region::EarlyBound(id) | Region::LateBound(_, _, id) | Region::Free(_, id) => Some(id), } } @@ -88,17 +78,6 @@ impl RegionExt for Region { _ => self, } } - - fn subst<'a, L>(self, mut params: L, map: &NamedRegionMap) -> Option<Region> - where - L: Iterator<Item = &'a hir::Lifetime>, - { - if let Region::EarlyBound(index, _) = self { - params.nth(index as usize).and_then(|lifetime| map.defs.get(&lifetime.hir_id).cloned()) - } else { - Some(self) - } - } } /// Maps the id of each lifetime reference to the lifetime decl @@ -131,9 +110,6 @@ pub(crate) struct LifetimeContext<'a, 'tcx> { /// be false if the `Item` we are resolving lifetimes for is not a trait or /// we eventually need lifetimes resolve for trait items. trait_definition_only: bool, - - /// Cache for cross-crate per-definition object lifetime defaults. - xcrate_object_lifetime_defaults: DefIdMap<Vec<ObjectLifetimeDefault>>, } #[derive(Debug)] @@ -147,25 +123,6 @@ enum Scope<'a> { /// for diagnostics. lifetimes: FxIndexMap<LocalDefId, Region>, - /// if we extend this scope with another scope, what is the next index - /// we should use for an early-bound region? - next_early_index: u32, - - /// Whether or not this binder would serve as the parent - /// binder for opaque types introduced within. For example: - /// - /// ```text - /// fn foo<'a>() -> impl for<'b> Trait<Item = impl Trait2<'a>> - /// ``` - /// - /// Here, the opaque types we create for the `impl Trait` - /// and `impl Trait2` references will both have the `foo` item - /// as their parent. When we get to `impl Trait2`, we find - /// that it is nested within the `for<>` binder -- this flag - /// allows us to skip that when looking for the parent binder - /// of the resulting opaque type. - opaque_type_parent: bool, - scope_type: BinderScopeType, /// The late bound vars for a given item are stored by `HirId` to be @@ -245,19 +202,9 @@ struct TruncatedScopeDebug<'a>(&'a Scope<'a>); impl<'a> fmt::Debug for TruncatedScopeDebug<'a> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { match self.0 { - Scope::Binder { - lifetimes, - next_early_index, - opaque_type_parent, - scope_type, - hir_id, - where_bound_origin, - s: _, - } => f + Scope::Binder { lifetimes, scope_type, hir_id, where_bound_origin, s: _ } => f .debug_struct("Binder") .field("lifetimes", lifetimes) - .field("next_early_index", next_early_index) - .field("opaque_type_parent", opaque_type_parent) .field("scope_type", scope_type) .field("hir_id", hir_id) .field("where_bound_origin", where_bound_origin) @@ -294,10 +241,7 @@ pub fn provide(providers: &mut ty::query::Providers) { named_region_map: |tcx, id| resolve_lifetimes_for(tcx, id).defs.get(&id), is_late_bound_map, - object_lifetime_defaults: |tcx, id| match tcx.hir().find_by_def_id(id) { - Some(Node::Item(item)) => compute_object_lifetime_defaults(tcx, item), - _ => None, - }, + object_lifetime_default, late_bound_vars_map: |tcx, id| resolve_lifetimes_for(tcx, id).late_bound_vars.get(&id), ..*providers @@ -334,7 +278,7 @@ pub fn provide(providers: &mut ty::query::Providers) { /// lifetimes into a single binder.) This requires us to resolve the /// *trait definition* of `Sub`; basically just enough lifetime information /// to look at the supertraits. -#[tracing::instrument(level = "debug", skip(tcx))] +#[instrument(level = "debug", skip(tcx))] fn resolve_lifetimes_trait_definition( tcx: TyCtxt<'_>, local_def_id: LocalDefId, @@ -345,7 +289,7 @@ fn resolve_lifetimes_trait_definition( /// Computes the `ResolveLifetimes` map that contains data for an entire `Item`. /// You should not read the result of this query directly, but rather use /// `named_region_map`, `is_late_bound_map`, etc. -#[tracing::instrument(level = "debug", skip(tcx))] +#[instrument(level = "debug", skip(tcx))] fn resolve_lifetimes(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> ResolveLifetimes { convert_named_region_map(do_resolve(tcx, local_def_id, false)) } @@ -363,7 +307,6 @@ fn do_resolve( map: &mut named_region_map, scope: ROOT_SCOPE, trait_definition_only, - xcrate_object_lifetime_defaults: Default::default(), }; visitor.visit_item(item); @@ -432,13 +375,6 @@ fn item_for(tcx: TyCtxt<'_>, local_def_id: LocalDefId) -> LocalDefId { item } -/// In traits, there is an implicit `Self` type parameter which comes before the generics. -/// We have to account for this when computing the index of the other generic parameters. -/// This function returns whether there is such an implicit parameter defined on the given item. -fn sub_items_have_self_param(node: &hir::ItemKind<'_>) -> bool { - matches!(*node, hir::ItemKind::Trait(..) | hir::ItemKind::TraitAlias(..)) -} - fn late_region_as_bound_region<'tcx>(tcx: TyCtxt<'tcx>, region: &Region) -> ty::BoundVariableKind { match region { Region::LateBound(_, _, def_id) => { @@ -558,7 +494,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } - let next_early_index = self.next_early_index(); let (lifetimes, binders): (FxIndexMap<LocalDefId, Region>, Vec<_>) = bound_generic_params .iter() @@ -576,8 +511,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { hir_id: e.hir_id, lifetimes, s: self.scope, - next_early_index, - opaque_type_parent: false, scope_type: BinderScopeType::Normal, where_bound_origin: None, }; @@ -592,6 +525,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } + #[instrument(level = "debug", skip(self))] fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) { match &item.kind { hir::ItemKind::Impl(hir::Impl { of_trait, .. }) => { @@ -603,7 +537,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } match item.kind { hir::ItemKind::Fn(_, ref generics, _) => { - self.visit_early_late(None, item.hir_id(), generics, |this| { + self.visit_early_late(item.hir_id(), generics, |this| { intravisit::walk_item(this, item); }); } @@ -670,31 +604,20 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { | hir::ItemKind::TraitAlias(ref generics, ..) | hir::ItemKind::Impl(hir::Impl { ref generics, .. }) => { // These kinds of items have only early-bound lifetime parameters. - let mut index = if sub_items_have_self_param(&item.kind) { - 1 // Self comes before lifetimes - } else { - 0 - }; - let mut non_lifetime_count = 0; let lifetimes = generics .params .iter() .filter_map(|param| match param.kind { GenericParamKind::Lifetime { .. } => { - Some(Region::early(self.tcx.hir(), &mut index, param)) - } - GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => { - non_lifetime_count += 1; - None + Some(Region::early(self.tcx.hir(), param)) } + GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => None, }) .collect(); self.map.late_bound_vars.insert(item.hir_id(), vec![]); let scope = Scope::Binder { hir_id: item.hir_id(), lifetimes, - next_early_index: index + non_lifetime_count, - opaque_type_parent: true, scope_type: BinderScopeType::Normal, s: ROOT_SCOPE, where_bound_origin: None, @@ -712,7 +635,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem<'tcx>) { match item.kind { hir::ForeignItemKind::Fn(_, _, ref generics) => { - self.visit_early_late(None, item.hir_id(), generics, |this| { + self.visit_early_late(item.hir_id(), generics, |this| { intravisit::walk_foreign_item(this, item); }) } @@ -725,11 +648,10 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) { match ty.kind { hir::TyKind::BareFn(ref c) => { - let next_early_index = self.next_early_index(); let (lifetimes, binders): (FxIndexMap<LocalDefId, Region>, Vec<_>) = c .generic_params .iter() @@ -746,8 +668,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { hir_id: ty.hir_id, lifetimes, s: self.scope, - next_early_index, - opaque_type_parent: false, scope_type: BinderScopeType::Normal, where_bound_origin: None, }; @@ -762,7 +682,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { let scope = Scope::TraitRefBoundary { s: self.scope }; self.with(scope, |this| { for bound in bounds { - this.visit_poly_trait_ref(bound, hir::TraitBoundModifier::None); + this.visit_poly_trait_ref(bound); } }); match lifetime.name { @@ -795,7 +715,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { }; self.with(scope, |this| this.visit_ty(&mt.ty)); } - hir::TyKind::OpaqueDef(item_id, lifetimes) => { + hir::TyKind::OpaqueDef(item_id, lifetimes, _in_trait) => { // Resolve the lifetimes in the bounds to the lifetime defs in the generics. // `fn foo<'a>() -> impl MyTrait<'a> { ... }` desugars to // `type MyAnonTy<'b> = impl MyTrait<'b>;` @@ -886,32 +806,23 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { // We want to start our early-bound indices at the end of the parent scope, // not including any parent `impl Trait`s. - let mut index = self.next_early_index_for_opaque_type(); - debug!(?index); - let mut lifetimes = FxIndexMap::default(); - let mut non_lifetime_count = 0; debug!(?generics.params); for param in generics.params { match param.kind { GenericParamKind::Lifetime { .. } => { - let (def_id, reg) = Region::early(self.tcx.hir(), &mut index, ¶m); + let (def_id, reg) = Region::early(self.tcx.hir(), ¶m); lifetimes.insert(def_id, reg); } - GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => { - non_lifetime_count += 1; - } + GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => {} } } - let next_early_index = index + non_lifetime_count; self.map.late_bound_vars.insert(ty.hir_id, vec![]); let scope = Scope::Binder { hir_id: ty.hir_id, lifetimes, - next_early_index, s: self.scope, - opaque_type_parent: false, scope_type: BinderScopeType::Normal, where_bound_origin: None, }; @@ -929,43 +840,32 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } + #[instrument(level = "debug", skip(self))] fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) { use self::hir::TraitItemKind::*; match trait_item.kind { Fn(_, _) => { - let tcx = self.tcx; - self.visit_early_late( - Some(tcx.hir().get_parent_item(trait_item.hir_id())), - trait_item.hir_id(), - &trait_item.generics, - |this| intravisit::walk_trait_item(this, trait_item), - ); + self.visit_early_late(trait_item.hir_id(), &trait_item.generics, |this| { + intravisit::walk_trait_item(this, trait_item) + }); } Type(bounds, ref ty) => { let generics = &trait_item.generics; - let mut index = self.next_early_index(); - debug!("visit_ty: index = {}", index); - let mut non_lifetime_count = 0; let lifetimes = generics .params .iter() .filter_map(|param| match param.kind { GenericParamKind::Lifetime { .. } => { - Some(Region::early(self.tcx.hir(), &mut index, param)) - } - GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => { - non_lifetime_count += 1; - None + Some(Region::early(self.tcx.hir(), param)) } + GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => None, }) .collect(); self.map.late_bound_vars.insert(trait_item.hir_id(), vec![]); let scope = Scope::Binder { hir_id: trait_item.hir_id(), lifetimes, - next_early_index: index + non_lifetime_count, s: self.scope, - opaque_type_parent: true, scope_type: BinderScopeType::Normal, where_bound_origin: None, }; @@ -990,43 +890,30 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } + #[instrument(level = "debug", skip(self))] fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) { use self::hir::ImplItemKind::*; match impl_item.kind { - Fn(..) => { - let tcx = self.tcx; - self.visit_early_late( - Some(tcx.hir().get_parent_item(impl_item.hir_id())), - impl_item.hir_id(), - &impl_item.generics, - |this| intravisit::walk_impl_item(this, impl_item), - ); - } + Fn(..) => self.visit_early_late(impl_item.hir_id(), &impl_item.generics, |this| { + intravisit::walk_impl_item(this, impl_item) + }), TyAlias(ref ty) => { let generics = &impl_item.generics; - let mut index = self.next_early_index(); - let mut non_lifetime_count = 0; - debug!("visit_ty: index = {}", index); let lifetimes: FxIndexMap<LocalDefId, Region> = generics .params .iter() .filter_map(|param| match param.kind { GenericParamKind::Lifetime { .. } => { - Some(Region::early(self.tcx.hir(), &mut index, param)) - } - GenericParamKind::Const { .. } | GenericParamKind::Type { .. } => { - non_lifetime_count += 1; - None + Some(Region::early(self.tcx.hir(), param)) } + GenericParamKind::Const { .. } | GenericParamKind::Type { .. } => None, }) .collect(); self.map.late_bound_vars.insert(ty.hir_id, vec![]); let scope = Scope::Binder { hir_id: ty.hir_id, lifetimes, - next_early_index: index + non_lifetime_count, s: self.scope, - opaque_type_parent: true, scope_type: BinderScopeType::Normal, where_bound_origin: None, }; @@ -1046,7 +933,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn visit_lifetime(&mut self, lifetime_ref: &'tcx hir::Lifetime) { match lifetime_ref.name { hir::LifetimeName::Static => self.insert_lifetime(lifetime_ref, Region::Static), @@ -1129,7 +1016,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { }) .unzip(); this.map.late_bound_vars.insert(bounded_ty.hir_id, binders.clone()); - let next_early_index = this.next_early_index(); // Even if there are no lifetimes defined here, we still wrap it in a binder // scope. If there happens to be a nested poly trait ref (an error), that // will be `Concatenating` anyways, so we don't have to worry about the depth @@ -1138,8 +1024,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { hir_id: bounded_ty.hir_id, lifetimes, s: this.scope, - next_early_index, - opaque_type_parent: false, scope_type: BinderScopeType::Normal, where_bound_origin: Some(origin), }; @@ -1210,8 +1094,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { hir_id: *hir_id, lifetimes: FxIndexMap::default(), s: self.scope, - next_early_index: self.next_early_index(), - opaque_type_parent: false, scope_type, where_bound_origin: None, }; @@ -1223,14 +1105,9 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } - fn visit_poly_trait_ref( - &mut self, - trait_ref: &'tcx hir::PolyTraitRef<'tcx>, - _modifier: hir::TraitBoundModifier, - ) { + fn visit_poly_trait_ref(&mut self, trait_ref: &'tcx hir::PolyTraitRef<'tcx>) { debug!("visit_poly_trait_ref(trait_ref={:?})", trait_ref); - let next_early_index = self.next_early_index(); let (mut binders, scope_type) = self.poly_trait_ref_binder_info(); let initial_bound_vars = binders.len() as u32; @@ -1260,8 +1137,6 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { hir_id: trait_ref.trait_ref.hir_ref_id, lifetimes, s: self.scope, - next_early_index, - opaque_type_parent: false, scope_type, where_bound_origin: None, }; @@ -1272,139 +1147,49 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> { } } -fn compute_object_lifetime_defaults<'tcx>( - tcx: TyCtxt<'tcx>, - item: &hir::Item<'_>, -) -> Option<&'tcx [ObjectLifetimeDefault]> { - match item.kind { - hir::ItemKind::Struct(_, ref generics) - | hir::ItemKind::Union(_, ref generics) - | hir::ItemKind::Enum(_, ref generics) - | hir::ItemKind::OpaqueTy(hir::OpaqueTy { - ref generics, - origin: hir::OpaqueTyOrigin::TyAlias, - .. - }) - | hir::ItemKind::TyAlias(_, ref generics) - | hir::ItemKind::Trait(_, _, ref generics, ..) => { - let result = object_lifetime_defaults_for_item(tcx, generics); - - // Debugging aid. - let attrs = tcx.hir().attrs(item.hir_id()); - if tcx.sess.contains_name(attrs, sym::rustc_object_lifetime_default) { - let object_lifetime_default_reprs: String = result - .iter() - .map(|set| match *set { - Set1::Empty => "BaseDefault".into(), - Set1::One(Region::Static) => "'static".into(), - Set1::One(Region::EarlyBound(mut i, _)) => generics - .params - .iter() - .find_map(|param| match param.kind { - GenericParamKind::Lifetime { .. } => { - if i == 0 { - return Some(param.name.ident().to_string().into()); - } - i -= 1; - None - } - _ => None, - }) - .unwrap(), - Set1::One(_) => bug!(), - Set1::Many => "Ambiguous".into(), - }) - .collect::<Vec<Cow<'static, str>>>() - .join(","); - tcx.sess.span_err(item.span, &object_lifetime_default_reprs); - } - - Some(result) - } - _ => None, - } -} - -/// Scan the bounds and where-clauses on parameters to extract bounds -/// of the form `T:'a` so as to determine the `ObjectLifetimeDefault` -/// for each type parameter. -fn object_lifetime_defaults_for_item<'tcx>( - tcx: TyCtxt<'tcx>, - generics: &hir::Generics<'_>, -) -> &'tcx [ObjectLifetimeDefault] { - fn add_bounds(set: &mut Set1<hir::LifetimeName>, bounds: &[hir::GenericBound<'_>]) { - for bound in bounds { - if let hir::GenericBound::Outlives(ref lifetime) = *bound { - set.insert(lifetime.name.normalize_to_macros_2_0()); - } - } - } - - let process_param = |param: &hir::GenericParam<'_>| match param.kind { - GenericParamKind::Lifetime { .. } => None, +fn object_lifetime_default<'tcx>(tcx: TyCtxt<'tcx>, param_def_id: DefId) -> ObjectLifetimeDefault { + debug_assert_eq!(tcx.def_kind(param_def_id), DefKind::TyParam); + let param_def_id = param_def_id.expect_local(); + let parent_def_id = tcx.local_parent(param_def_id); + let generics = tcx.hir().get_generics(parent_def_id).unwrap(); + let param_hir_id = tcx.local_def_id_to_hir_id(param_def_id); + let param = generics.params.iter().find(|p| p.hir_id == param_hir_id).unwrap(); + + // Scan the bounds and where-clauses on parameters to extract bounds + // of the form `T:'a` so as to determine the `ObjectLifetimeDefault` + // for each type parameter. + match param.kind { GenericParamKind::Type { .. } => { let mut set = Set1::Empty; - let param_def_id = tcx.hir().local_def_id(param.hir_id); - for predicate in generics.predicates { - // Look for `type: ...` where clauses. - let hir::WherePredicate::BoundPredicate(ref data) = *predicate else { continue }; - + // Look for `type: ...` where clauses. + for bound in generics.bounds_for_param(param_def_id) { // Ignore `for<'a> type: ...` as they can change what // lifetimes mean (although we could "just" handle it). - if !data.bound_generic_params.is_empty() { + if !bound.bound_generic_params.is_empty() { continue; } - let res = match data.bounded_ty.kind { - hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) => path.res, - _ => continue, - }; - - if res == Res::Def(DefKind::TyParam, param_def_id.to_def_id()) { - add_bounds(&mut set, &data.bounds); + for bound in bound.bounds { + if let hir::GenericBound::Outlives(ref lifetime) = *bound { + set.insert(lifetime.name.normalize_to_macros_2_0()); + } } } - Some(match set { - Set1::Empty => Set1::Empty, - Set1::One(name) => { - if name == hir::LifetimeName::Static { - Set1::One(Region::Static) - } else { - generics - .params - .iter() - .filter_map(|param| match param.kind { - GenericParamKind::Lifetime { .. } => { - let param_def_id = tcx.hir().local_def_id(param.hir_id); - Some(( - param_def_id, - hir::LifetimeName::Param(param_def_id, param.name), - )) - } - _ => None, - }) - .enumerate() - .find(|&(_, (_, lt_name))| lt_name == name) - .map_or(Set1::Many, |(i, (def_id, _))| { - Set1::One(Region::EarlyBound(i as u32, def_id.to_def_id())) - }) - } + match set { + Set1::Empty => ObjectLifetimeDefault::Empty, + Set1::One(hir::LifetimeName::Static) => ObjectLifetimeDefault::Static, + Set1::One(hir::LifetimeName::Param(param_def_id, _)) => { + ObjectLifetimeDefault::Param(param_def_id.to_def_id()) } - Set1::Many => Set1::Many, - }) + _ => ObjectLifetimeDefault::Ambiguous, + } } - GenericParamKind::Const { .. } => { - // Generic consts don't impose any constraints. - // - // We still store a dummy value here to allow generic parameters - // in an arbitrary order. - Some(Set1::Empty) + _ => { + bug!("object_lifetime_default_raw must only be called on a type parameter") } - }; - - tcx.arena.alloc_from_iter(generics.params.iter().filter_map(process_param)) + } } impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { @@ -1413,20 +1198,17 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { F: for<'b> FnOnce(&mut LifetimeContext<'b, 'tcx>), { let LifetimeContext { tcx, map, .. } = self; - let xcrate_object_lifetime_defaults = take(&mut self.xcrate_object_lifetime_defaults); let mut this = LifetimeContext { tcx: *tcx, map, scope: &wrap_scope, trait_definition_only: self.trait_definition_only, - xcrate_object_lifetime_defaults, }; - let span = tracing::debug_span!("scope", scope = ?TruncatedScopeDebug(&this.scope)); + let span = debug_span!("scope", scope = ?TruncatedScopeDebug(&this.scope)); { let _enter = span.enter(); f(&mut this); } - self.xcrate_object_lifetime_defaults = this.xcrate_object_lifetime_defaults; } /// Visits self by adding a scope and handling recursive walk over the contents with `walk`. @@ -1449,30 +1231,12 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { /// ordering is not important there. fn visit_early_late<F>( &mut self, - parent_id: Option<LocalDefId>, hir_id: hir::HirId, generics: &'tcx hir::Generics<'tcx>, walk: F, ) where F: for<'b, 'c> FnOnce(&'b mut LifetimeContext<'c, 'tcx>), { - // Find the start of nested early scopes, e.g., in methods. - let mut next_early_index = 0; - if let Some(parent_id) = parent_id { - let parent = self.tcx.hir().expect_item(parent_id); - if sub_items_have_self_param(&parent.kind) { - next_early_index += 1; // Self comes before lifetimes - } - match parent.kind { - hir::ItemKind::Trait(_, _, ref generics, ..) - | hir::ItemKind::Impl(hir::Impl { ref generics, .. }) => { - next_early_index += generics.params.len() as u32; - } - _ => {} - } - } - - let mut non_lifetime_count = 0; let mut named_late_bound_vars = 0; let lifetimes: FxIndexMap<LocalDefId, Region> = generics .params @@ -1484,16 +1248,12 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { named_late_bound_vars += 1; Some(Region::late(late_bound_idx, self.tcx.hir(), param)) } else { - Some(Region::early(self.tcx.hir(), &mut next_early_index, param)) + Some(Region::early(self.tcx.hir(), param)) } } - GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => { - non_lifetime_count += 1; - None - } + GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => None, }) .collect(); - let next_early_index = next_early_index + non_lifetime_count; let binders: Vec<_> = generics .params @@ -1512,52 +1272,14 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { let scope = Scope::Binder { hir_id, lifetimes, - next_early_index, s: self.scope, - opaque_type_parent: true, scope_type: BinderScopeType::Normal, where_bound_origin: None, }; self.with(scope, walk); } - fn next_early_index_helper(&self, only_opaque_type_parent: bool) -> u32 { - let mut scope = self.scope; - loop { - match *scope { - Scope::Root => return 0, - - Scope::Binder { next_early_index, opaque_type_parent, .. } - if (!only_opaque_type_parent || opaque_type_parent) => - { - return next_early_index; - } - - Scope::Binder { s, .. } - | Scope::Body { s, .. } - | Scope::Elision { s, .. } - | Scope::ObjectLifetimeDefault { s, .. } - | Scope::Supertrait { s, .. } - | Scope::TraitRefBoundary { s, .. } => scope = s, - } - } - } - - /// Returns the next index one would use for an early-bound-region - /// if extending the current scope. - fn next_early_index(&self) -> u32 { - self.next_early_index_helper(true) - } - - /// Returns the next index one would use for an `impl Trait` that - /// is being converted into an opaque type alias `impl Trait`. This will be the - /// next early index from the enclosing item, for the most - /// part. See the `opaque_type_parent` field for more info. - fn next_early_index_for_opaque_type(&self) -> u32 { - self.next_early_index_helper(false) - } - - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn resolve_lifetime_ref( &mut self, region_def_id: LocalDefId, @@ -1638,7 +1360,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { return; } - // We may fail to resolve higher-ranked lifetimes that are mentionned by APIT. + // We may fail to resolve higher-ranked lifetimes that are mentioned by APIT. // AST-based resolution does not care for impl-trait desugaring, which are the // responibility of lowering. This may create a mismatch between the resolution // AST found (`region_def_id`) which points to HRTB, and what HIR allows. @@ -1679,17 +1401,13 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { ); } + #[instrument(level = "debug", skip(self))] fn visit_segment_args( &mut self, res: Res, depth: usize, generic_args: &'tcx hir::GenericArgs<'tcx>, ) { - debug!( - "visit_segment_args(res={:?}, depth={:?}, generic_args={:?})", - res, depth, generic_args, - ); - if generic_args.parenthesized { self.visit_fn_like_elision( generic_args.inputs(), @@ -1707,13 +1425,9 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { // Figure out if this is a type/trait segment, // which requires object lifetime defaults. - let parent_def_id = |this: &mut Self, def_id: DefId| { - let def_key = this.tcx.def_key(def_id); - DefId { krate: def_id.krate, index: def_key.parent.expect("missing parent") } - }; let type_def_id = match res { - Res::Def(DefKind::AssocTy, def_id) if depth == 1 => Some(parent_def_id(self, def_id)), - Res::Def(DefKind::Variant, def_id) if depth == 0 => Some(parent_def_id(self, def_id)), + Res::Def(DefKind::AssocTy, def_id) if depth == 1 => Some(self.tcx.parent(def_id)), + Res::Def(DefKind::Variant, def_id) if depth == 0 => Some(self.tcx.parent(def_id)), Res::Def( DefKind::Struct | DefKind::Union @@ -1725,7 +1439,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { _ => None, }; - debug!("visit_segment_args: type_def_id={:?}", type_def_id); + debug!(?type_def_id); // Compute a vector of defaults, one for each type parameter, // per the rules given in RFCs 599 and 1156. Example: @@ -1763,55 +1477,52 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { }; let map = &self.map; - let set_to_region = |set: &ObjectLifetimeDefault| match *set { - Set1::Empty => { + let generics = self.tcx.generics_of(def_id); + + // `type_def_id` points to an item, so there is nothing to inherit generics from. + debug_assert_eq!(generics.parent_count, 0); + + let set_to_region = |set: ObjectLifetimeDefault| match set { + ObjectLifetimeDefault::Empty => { if in_body { None } else { Some(Region::Static) } } - Set1::One(r) => { - let lifetimes = generic_args.args.iter().filter_map(|arg| match arg { - GenericArg::Lifetime(lt) => Some(lt), + ObjectLifetimeDefault::Static => Some(Region::Static), + ObjectLifetimeDefault::Param(param_def_id) => { + // This index can be used with `generic_args` since `parent_count == 0`. + let index = generics.param_def_id_to_index[¶m_def_id] as usize; + generic_args.args.get(index).and_then(|arg| match arg { + GenericArg::Lifetime(lt) => map.defs.get(<.hir_id).copied(), _ => None, - }); - r.subst(lifetimes, map) + }) } - Set1::Many => None, + ObjectLifetimeDefault::Ambiguous => None, }; - if let Some(def_id) = def_id.as_local() { - let id = self.tcx.hir().local_def_id_to_hir_id(def_id); - self.tcx - .object_lifetime_defaults(id.owner) - .unwrap() - .iter() - .map(set_to_region) - .collect() - } else { - let tcx = self.tcx; - self.xcrate_object_lifetime_defaults - .entry(def_id) - .or_insert_with(|| { - tcx.generics_of(def_id) - .params - .iter() - .filter_map(|param| match param.kind { - GenericParamDefKind::Type { object_lifetime_default, .. } => { - Some(object_lifetime_default) - } - GenericParamDefKind::Const { .. } => Some(Set1::Empty), - GenericParamDefKind::Lifetime => None, - }) - .collect() - }) - .iter() - .map(set_to_region) - .collect() - } + generics + .params + .iter() + .filter_map(|param| { + match self.tcx.def_kind(param.def_id) { + // Generic consts don't impose any constraints. + // + // We still store a dummy value here to allow generic parameters + // in an arbitrary order. + DefKind::ConstParam => Some(ObjectLifetimeDefault::Empty), + DefKind::TyParam => Some(self.tcx.object_lifetime_default(param.def_id)), + // We may also get a `Trait` or `TraitAlias` because of how generics `Self` parameter + // works. Ignore it because it can't have a meaningful lifetime default. + DefKind::LifetimeParam | DefKind::Trait | DefKind::TraitAlias => None, + dk => bug!("unexpected def_kind {:?}", dk), + } + }) + .map(set_to_region) + .collect() }); - debug!("visit_segment_args: object_lifetime_defaults={:?}", object_lifetime_defaults); + debug!(?object_lifetime_defaults); let mut i = 0; for arg in generic_args.args { @@ -1953,7 +1664,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { } } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn visit_fn_like_elision( &mut self, inputs: &'tcx [hir::Ty<'tcx>], @@ -2001,7 +1712,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { self.insert_lifetime(lifetime_ref, lifetime.shifted(late_depth)); } - #[tracing::instrument(level = "debug", skip(self))] + #[instrument(level = "debug", skip(self))] fn insert_lifetime(&mut self, lifetime_ref: &'tcx hir::Lifetime, def: Region) { debug!( node = ?self.tcx.hir().node_to_string(lifetime_ref.hir_id), @@ -2112,7 +1823,7 @@ fn is_late_bound_map(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<&FxIndexSet< // is, those would be potentially inputs to // projections if let Some(last_segment) = path.segments.last() { - self.visit_path_segment(path.span, last_segment); + self.visit_path_segment(last_segment); } } |