Rollup of 25 pull requests

.mailmap

@@ -562,6 +562,7 @@ Paul Faria <paul_faria@ultimatesoftware.com> Paul Faria <Nashenas88@gmail.com>
 Peer Aramillo Irizar <peer.aramillo.irizar@gmail.com> parir <peer.aramillo.irizar@gmail.com>
 Peter Elmers <peter.elmers@yahoo.com> <peter.elmers@rice.edu>
 Peter Liniker <peter.liniker+github@gmail.com>
+Petr Hosek <petrhosek@gmail.com> <phosek@google.com>
 Phil Dawes <phil@phildawes.net> Phil Dawes <pdawes@drw.com>
 Phil Hansch <dev@phansch.net>
 Philipp Brüschweiler <blei42@gmail.com> <blei42@gmail.com>
@@ -720,6 +721,7 @@ Wilfred Hughes <me@wilfred.me.uk>
 Wilfred Hughes <me@wilfred.me.uk> <wilfred@meta.com>
 Will Crichton <crichton.will@gmail.com> <wcrichto@stanford.edu>
 Will Crichton <crichton.will@gmail.com> <wcrichto@cs.stanford.edu>
+Will Crichton <crichton.will@gmail.com> <will_crichton@brown.edu>
 William Ting <io@williamting.com> <william.h.ting@gmail.com>
 Wim Looman <wim@nemo157.com> <rust-lang@nemo157.com>
 Wim Looman <wim@nemo157.com> <git@nemo157.com>

compiler/rustc_ast/src/token.rs

@@ -308,8 +308,13 @@ impl LitKind {
 }
 
 pub fn ident_can_begin_expr(name: Symbol, span: Span, is_raw: IdentIsRaw) -> bool {
+    // WARNING: Take care when modifying this function! It will change the stable(!) set of
+    //          tokens that are allowed to match an `expr` nonterminal which is user observable.
+
     let ident_token = Token::new(Ident(name, is_raw), span);
 
+    // FIXME: Remove `box` from this list given we officially no longer support box expressions
+    //        (#108471) (needs lang FCP as it affects stable macro matching behavior).
     !ident_token.is_reserved_ident()
         || ident_token.is_path_segment_keyword()
         || [
@@ -340,6 +345,9 @@ pub fn ident_can_begin_expr(name: Symbol, span: Span, is_raw: IdentIsRaw) -> boo
 }
 
 fn ident_can_begin_type(name: Symbol, span: Span, is_raw: IdentIsRaw) -> bool {
+    // WARNING: Take care when modifying this function! It will change the stable(!) set of
+    //          tokens that are allowed to match an `ty` nonterminal which is user observable.
+
     let ident_token = Token::new(Ident(name, is_raw), span);
 
     !ident_token.is_reserved_ident()
@@ -661,10 +669,10 @@ impl Token {
     }
 
     /// Returns `true` if the token can appear at the start of an expression.
-    ///
-    /// **NB**: Take care when modifying this function, since it will change
-    /// the stable set of tokens that are allowed to match an expr nonterminal.
     pub fn can_begin_expr(&self) -> bool {
+        // WARNING: Take care when modifying this function! It will change the stable(!) set of
+        //          tokens that are allowed to match an `expr` nonterminal which is user observable.
+
         match self.uninterpolate().kind {
             Ident(name, is_raw)              =>
                 ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
@@ -695,9 +703,10 @@ impl Token {
     }
 
     /// Returns `true` if the token can appear at the start of a pattern.
-    ///
-    /// Shamelessly borrowed from `can_begin_expr`.
     pub fn can_begin_pattern(&self, pat_kind: NtPatKind) -> bool {
+        // WARNING: Take care when modifying this function! It will change the stable(!) set of
+        //          tokens that are allowed to match an `pat` nonterminal which is user observable.
+
         match &self.uninterpolate().kind {
             // box, ref, mut, and other identifiers (can stricten)
             Ident(..) | NtIdent(..) |
@@ -727,6 +736,12 @@ impl Token {
 
     /// Returns `true` if the token can appear at the start of a type.
     pub fn can_begin_type(&self) -> bool {
+        // WARNING: Take care when modifying this function! It will change the stable(!) set of
+        //          tokens that are allowed to match an `ty` nonterminal which is user observable.
+
+        // FIXME: Arguably, `use` should be included in this list since it can begin bare trait
+        //        object types (consider `use<>+` and `use<T> + Trait` for example).
+
         match self.uninterpolate().kind {
             Ident(name, is_raw) =>
                 ident_can_begin_type(name, self.span, is_raw), // type name or keyword

compiler/rustc_ast_lowering/src/delegation/attributes.rs

@@ -43,17 +43,17 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let &DelegationResolution { span, sig_id, .. } = resolution;
 
         const PARENT_ID: hir::ItemLocalId = hir::ItemLocalId::ZERO;
-        let new_attrs = self.create_new_attrs(span, sig_id, self.attrs.get(&PARENT_ID));
+        let new_attrs = self.create_new_attrs(span, sig_id, self.curr_owner.attrs.get(&PARENT_ID));
 
         if !new_attrs.is_empty() {
-            let new_attrs = match self.attrs.get(&PARENT_ID) {
+            let new_attrs = match self.curr_owner.attrs.get(&PARENT_ID) {
                 Some(existing_attrs) => self.arena.alloc_from_iter(
                     existing_attrs.iter().map(|a| a.clone()).chain(new_attrs.into_iter()),
                 ),
                 None => self.arena.alloc_from_iter(new_attrs.into_iter()),
             };
 
-            self.attrs.insert(PARENT_ID, new_attrs);
+            self.curr_owner.attrs.insert(PARENT_ID, new_attrs);
         }
     }
 

compiler/rustc_ast_lowering/src/delegation/generics.rs

@@ -587,7 +587,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             };
 
             // Important: we don't use `self.next_id()` as we want to execute
-            // `lower_node_id` routine so param's id is added to `self.children`.
+            // `lower_node_id` routine so param's id is added to `self.curr_owner.children`.
             let hir_id = self.lower_node_id(node_id);
 
             Some(hir::GenericParam {

compiler/rustc_ast_lowering/src/delegation/mod.rs

@@ -140,9 +140,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         let id = match source {
                             DelegationSource::Single => None,
                             DelegationSource::List(expn_id) => Some(expn_id),
-                            DelegationSource::Glob => {
-                                Some(self.tcx.expn_that_defined(self.owner.def_id).expect_local())
-                            }
+                            DelegationSource::Glob => Some(
+                                self.tcx
+                                    .expn_that_defined(self.curr_owner.owner.def_id)
+                                    .expect_local(),
+                            ),
                         };
 
                         id.map(|id| (id, unused_target_expr))
@@ -335,7 +337,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let overwrites = self_resolver.overwrites;
 
         // Target expr needs to lower `self` path.
-        self.ident_and_label_to_local_id.insert(pat_node_id, param_local_id);
+        self.curr_owner.ident_and_label_to_local_id.insert(pat_node_id, param_local_id);
 
         let block = cfg_select! {
             debug_assertions => {

compiler/rustc_ast_lowering/src/delegation/resolution.rs

@@ -73,7 +73,7 @@ pub(super) mod resolver {
 
         #[inline]
         pub(crate) fn owner_id(&self) -> LocalDefId {
-            self.0.owner.def_id
+            self.0.curr_owner.owner.def_id
         }
 
         /// (from `tests\ui\delegation\target-expr-removal-defs-inside.rs`):
@@ -91,7 +91,7 @@ pub(super) mod resolver {
         #[inline]
         pub(crate) fn is_definition(&self, id: NodeId) -> bool {
             self.0.resolver.owners.contains_key(&id)
-                || self.0.owner.node_id_to_def_id.contains_key(&id)
+                || self.0.curr_owner.owner.node_id_to_def_id.contains_key(&id)
         }
 
         #[inline]

compiler/rustc_ast_lowering/src/expr.rs

@@ -172,7 +172,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 // Merge attributes into the inner expression.
                 if !e.attrs.is_empty() {
-                    let old_attrs = self.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
+                    let old_attrs =
+                        self.curr_owner.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
                     let new_attrs = self
                         .lower_attrs_vec(&e.attrs, e.span, ex.hir_id, Target::from_expr(e))
                         .into_iter()
@@ -181,7 +182,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     if new_attrs.is_empty() {
                         return ex;
                     }
-                    self.attrs.insert(ex.hir_id.local_id, new_attrs);
+                    self.curr_owner.attrs.insert(ex.hir_id.local_id, new_attrs);
                 }
                 return ex;
             }
@@ -884,15 +885,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
     /// `inner_hir_id` in case the `async_fn_track_caller` feature is enabled.
     pub(super) fn maybe_forward_track_caller(&mut self, outer_hir_id: HirId, inner_hir_id: HirId) {
         if self.tcx.features().async_fn_track_caller()
-            && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
+            && let Some(attrs) = self.curr_owner.attrs.get(&outer_hir_id.local_id)
             && let Some(t) = attrs.iter().find(|a| {
                 matches!(
                     a,
                     rustc_attr_ir::Attribute::Parsed(rustc_attr_ir::AttributeKind::TrackCaller(_))
                 )
             })
         {
-            self.attrs.insert(inner_hir_id.local_id, std::slice::from_ref(t));
+            self.curr_owner.attrs.insert(inner_hir_id.local_id, std::slice::from_ref(t));
         }
     }
 
@@ -1505,16 +1506,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
         dest_hir_id: hir::HirId,
     ) -> Option<Label> {
         let label = opt_label?;
-        self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
+        self.curr_owner.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
         Some(Label { ident: self.lower_ident(label.ident) })
     }
 
     fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
         let target_id = match destination {
             Some((id, _)) => {
-                if let Some(loop_id) = self.owner.get_label_res(id) {
-                    let local_id = self.ident_and_label_to_local_id[&loop_id];
-                    let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
+                if let Some(loop_id) = self.curr_owner.owner.get_label_res(id) {
+                    let local_id = self.curr_owner.ident_and_label_to_local_id[&loop_id];
+                    let loop_hir_id = HirId { owner: self.curr_owner.owner_id, local_id };
                     Ok(loop_hir_id)
                 } else {
                     Err(hir::LoopIdError::UnresolvedLabel)

compiler/rustc_ast_lowering/src/item.rs

@@ -61,17 +61,15 @@ impl<'hir> ItemLowerer<'_, 'hir> {
         let mut lctx = LoweringContext::new(self.tcx, self.resolver, owner);
 
         let item = f(&mut lctx);
-        debug_assert_eq!(lctx.current_hir_id_owner, item.def_id());
-
-        let info = lctx.make_owner_info(item);
 
+        let info = lctx.curr_owner.into_owner_info(self.tcx, item);
         hir::MaybeOwner::Owner(lctx.arena.alloc(info))
     }
 
     #[instrument(level = "debug", skip(self, c))]
     pub(super) fn lower_crate(&mut self, c: &Crate) -> hir::MaybeOwner<'hir> {
         self.with_lctx(CRATE_NODE_ID, |lctx| {
-            debug_assert_eq!(lctx.current_hir_id_owner, CRATE_OWNER_ID);
+            debug_assert_eq!(lctx.curr_owner.owner_id, CRATE_OWNER_ID);
             let module = lctx.lower_mod(&c.items, &c.spans);
             lctx.lower_attrs(hir::CRATE_HIR_ID, &c.attrs, c.spans.inner_span, Target::Crate);
             hir::OwnerNode::Crate(module)
@@ -206,7 +204,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_item(&mut self, i: &Item) -> &'hir hir::Item<'hir> {
-        let owner_id = self.current_hir_id_owner;
+        let owner_id = self.curr_owner.owner_id;
         let hir_id: HirId = owner_id.into();
         let vis_span = self.lower_span(i.vis.span);
 
@@ -399,7 +397,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             ty,
                             ImplTraitContext::OpaqueTy {
                                 origin: hir::OpaqueTyOrigin::TyAlias {
-                                    parent: this.owner.def_id,
+                                    parent: this.curr_owner.owner.def_id,
                                     in_assoc_ty: false,
                                 },
                             },
@@ -547,7 +545,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             ItemKind::MacroDef(ident, MacroDef { body, macro_rules, eii_declaration: _ }) => {
                 let ident = self.lower_ident(*ident);
                 let body = Box::new(self.lower_delim_args(body));
-                let def_id = self.owner.def_id;
+                let def_id = self.curr_owner.owner.def_id;
                 let def_kind = self.tcx.def_kind(def_id);
                 let DefKind::Macro(macro_kinds) = def_kind else {
                     unreachable!(
@@ -695,7 +693,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         // `ItemLocalId` and the new owner. (See `lower_node_id`)
                         let kind = this.lower_use_tree(use_tree, &prefix, id, vis_span, attrs);
                         if !attrs.is_empty() {
-                            this.attrs.insert(hir::ItemLocalId::ZERO, attrs);
+                            this.curr_owner.attrs.insert(hir::ItemLocalId::ZERO, attrs);
                         }
 
                         let item = hir::Item {
@@ -731,7 +729,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_foreign_item(&mut self, i: &ForeignItem) -> &'hir hir::ForeignItem<'hir> {
-        let owner_id = self.current_hir_id_owner;
+        let owner_id = self.curr_owner.owner_id;
         let hir_id: HirId = owner_id.into();
         let attrs =
             self.lower_attrs(hir_id, &i.attrs, i.span, Target::from_foreign_item_kind(&i.kind));
@@ -914,7 +912,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_trait_item(&mut self, i: &AssocItem) -> &'hir hir::TraitItem<'hir> {
-        let trait_item_def_id = self.current_hir_id_owner;
+        let trait_item_def_id = self.curr_owner.owner_id;
         let hir_id: HirId = trait_item_def_id.into();
         let attrs = self.lower_attrs(
             hir_id,
@@ -1169,7 +1167,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_impl_item(&mut self, i: &AssocItem) -> &'hir hir::ImplItem<'hir> {
-        let owner_id = self.current_hir_id_owner;
+        let owner_id = self.curr_owner.owner_id;
         let hir_id: HirId = owner_id.into();
         let parent_id = self.tcx.local_parent(owner_id.def_id);
         let is_in_trait_impl =
@@ -1258,7 +1256,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                                     ty,
                                     ImplTraitContext::OpaqueTy {
                                         origin: hir::OpaqueTyOrigin::TyAlias {
-                                            parent: this.owner.def_id,
+                                            parent: this.curr_owner.owner.def_id,
                                             in_assoc_ty: true,
                                         },
                                     },
@@ -1336,8 +1334,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
     ) -> hir::BodyId {
         let body = hir::Body { params, value: self.arena.alloc(value) };
         let id = body.id();
-        assert_eq!(id.hir_id.owner, self.current_hir_id_owner);
-        self.bodies.push((id.hir_id.local_id, self.arena.alloc(body)));
+        assert_eq!(id.hir_id.owner, self.curr_owner.owner_id);
+        self.curr_owner.bodies.push((id.hir_id.local_id, self.arena.alloc(body)));
         id
     }
 
@@ -1545,7 +1543,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             //
             // If this is the simple case, this parameter will end up being the same as the
             // original parameter, but with a different pattern id.
-            let stmt_attrs = self.attrs.get(&parameter.hir_id.local_id).copied();
+            let stmt_attrs = self.curr_owner.attrs.get(&parameter.hir_id.local_id).copied();
             let (new_parameter_pat, new_parameter_id) = self.pat_ident(desugared_span, ident);
             let new_parameter = hir::Param {
                 hir_id: parameter.hir_id,
@@ -1883,8 +1881,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
         itctx: ImplTraitContext,
         f: impl FnOnce(&mut Self) -> T,
     ) -> (&'hir hir::Generics<'hir>, T) {
-        assert!(self.impl_trait_defs.is_empty());
-        assert!(self.impl_trait_bounds.is_empty());
+        assert!(self.curr_owner.impl_trait_defs.is_empty());
+        assert!(self.curr_owner.impl_trait_bounds.is_empty());
 
         let mut predicates: SmallVec<[hir::WherePredicate<'hir>; 4]> = SmallVec::new();
         // We need to make sure that generic params don't have multiple relaxed bounds for the same trait
@@ -1914,7 +1912,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             .collect();
 
         // Introduce extra lifetimes if late resolution tells us to.
-        let extra_lifetimes = self.owner.extra_lifetime_params(self.owner.id);
+        let extra_lifetimes = self.curr_owner.owner.extra_lifetime_params(self.curr_owner.owner.id);
         params.extend(extra_lifetimes.into_iter().map(|&(ident, node_id, kind)| {
             self.lifetime_res_to_generic_param(
                 ident,
@@ -1929,10 +1927,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let span = self.lower_span(generics.span);
         let res = f(self);
 
-        let impl_trait_defs = std::mem::take(&mut self.impl_trait_defs);
+        let impl_trait_defs = std::mem::take(&mut self.curr_owner.impl_trait_defs);
         params.extend(impl_trait_defs.into_iter());
 
-        let impl_trait_bounds = std::mem::take(&mut self.impl_trait_bounds);
+        let impl_trait_bounds = std::mem::take(&mut self.curr_owner.impl_trait_bounds);
         predicates.extend(impl_trait_bounds.into_iter());
 
         let lowered_generics = self.arena.alloc(hir::Generics {
@@ -1951,7 +1949,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         hir_id: HirId,
         define_opaque: &Option<ThinVec<(NodeId, Path)>>,
     ) {
-        assert_eq!(self.define_opaque, None);
+        assert_eq!(self.curr_owner.define_opaque, None);
         assert!(hir_id.is_owner());
         let Some(define_opaque) = define_opaque.as_ref() else {
             return;
@@ -1972,7 +1970,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             Some((self.lower_span(path.span), did))
         });
         let define_opaque = self.arena.alloc_from_iter(define_opaque);
-        self.define_opaque = Some(define_opaque);
+        self.curr_owner.define_opaque = Some(define_opaque);
     }
 
     pub(super) fn lower_generic_bound_predicate(