Rollup of 9 pull requests

compiler/rustc_ast/src/token.rs

@@ -486,6 +486,9 @@ 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 {
         match self.uninterpolate().kind {
             Ident(name, is_raw)              =>
@@ -504,34 +507,46 @@ impl Token {
             PathSep                            | // global path
             Lifetime(..)                      | // labeled loop
             Pound                             => true, // expression attributes
-            Interpolated(ref nt) => matches!(&**nt, NtLiteral(..) |
-                NtExpr(..)    |
-                NtBlock(..)   |
-                NtPath(..)),
+            Interpolated(ref nt) =>
+                matches!(&**nt,
+                    NtBlock(..)   |
+                    NtExpr(..)    |
+                    NtLiteral(..) |
+                    NtPath(..)
+                ),
             _ => false,
         }
     }
 
     /// Returns `true` if the token can appear at the start of a pattern.
     ///
     /// Shamelessly borrowed from `can_begin_expr`, only used for diagnostics right now.
-    pub fn can_begin_pattern(&self) -> bool {
-        match self.uninterpolate().kind {
-            Ident(name, is_raw)              =>
-                ident_can_begin_expr(name, self.span, is_raw), // value name or keyword
-            | OpenDelim(Delimiter::Bracket | Delimiter::Parenthesis)  // tuple or array
-            | Literal(..)                        // literal
-            | BinOp(Minus)                       // unary minus
-            | BinOp(And)                         // reference
-            | AndAnd                             // double reference
-            // DotDotDot is no longer supported
-            | DotDot | DotDotDot | DotDotEq      // ranges
-            | Lt | BinOp(Shl)                    // associated path
-            | PathSep                    => true, // global path
-            Interpolated(ref nt) => matches!(&**nt, NtLiteral(..) |
-                NtPat(..)     |
-                NtBlock(..)   |
-                NtPath(..)),
+    pub fn can_begin_pattern(&self, pat_kind: NtPatKind) -> bool {
+        match &self.uninterpolate().kind {
+            // box, ref, mut, and other identifiers (can stricten)
+            Ident(..) | NtIdent(..) |
+            OpenDelim(Delimiter::Parenthesis) |  // tuple pattern
+            OpenDelim(Delimiter::Bracket) |      // slice pattern
+            BinOp(And) |                  // reference
+            BinOp(Minus) |                // negative literal
+            AndAnd |                      // double reference
+            Literal(_) |                  // literal
+            DotDot |                      // range pattern (future compat)
+            DotDotDot |                   // range pattern (future compat)
+            PathSep |                     // path
+            Lt |                          // path (UFCS constant)
+            BinOp(Shl) => true,           // path (double UFCS)
+            // leading vert `|` or-pattern
+            BinOp(Or) => matches!(pat_kind, PatWithOr),
+            Interpolated(nt) =>
+                matches!(&**nt,
+                    | NtExpr(..)
+                    | NtLiteral(..)
+                    | NtMeta(..)
+                    | NtPat(..)
+                    | NtPath(..)
+                    | NtTy(..)
+                ),
             _ => false,
         }
     }

compiler/rustc_const_eval/src/interpret/visitor.rs

@@ -25,14 +25,15 @@ pub trait ValueVisitor<'tcx, M: Machine<'tcx>>: Sized {
     }
 
     /// This function provides the chance to reorder the order in which fields are visited for
-    /// `FieldsShape::Aggregate`: The order of fields will be
-    /// `(0..num_fields).map(aggregate_field_order)`.
+    /// `FieldsShape::Aggregate`.
     ///
-    /// The default means we iterate in source declaration order; alternative this can do an inverse
-    /// lookup in `memory_index` to use memory field order instead.
+    /// The default means we iterate in source declaration order; alternatively this can do some
+    /// work with `memory_index` to iterate in memory order.
     #[inline(always)]
-    fn aggregate_field_order(_memory_index: &IndexVec<FieldIdx, u32>, idx: usize) -> usize {
-        idx
+    fn aggregate_field_iter(
+        memory_index: &IndexVec<FieldIdx, u32>,
+    ) -> impl Iterator<Item = FieldIdx> + 'static {
+        memory_index.indices()
     }
 
     // Recursive actions, ready to be overloaded.
@@ -172,9 +173,9 @@ pub trait ValueVisitor<'tcx, M: Machine<'tcx>>: Sized {
             &FieldsShape::Union(fields) => {
                 self.visit_union(v, fields)?;
             }
-            FieldsShape::Arbitrary { offsets, memory_index } => {
-                for idx in 0..offsets.len() {
-                    let idx = Self::aggregate_field_order(memory_index, idx);
+            FieldsShape::Arbitrary { memory_index, .. } => {
+                for idx in Self::aggregate_field_iter(memory_index) {
+                    let idx = idx.as_usize();
                     let field = self.ecx().project_field(v, idx)?;
                     self.visit_field(v, idx, &field)?;
                 }

compiler/rustc_hir_analysis/src/collect.rs

@@ -420,7 +420,7 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
         span: Span,
         def_id: LocalDefId,
         assoc_name: Ident,
-    ) -> ty::GenericPredicates<'tcx> {
+    ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
         self.tcx.at(span).type_param_predicates((self.item_def_id, def_id, assoc_name))
     }
 

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -580,24 +580,24 @@ pub(super) fn explicit_predicates_of<'tcx>(
 /// Ensures that the super-predicates of the trait with a `DefId`
 /// of `trait_def_id` are lowered and stored. This also ensures that
 /// the transitive super-predicates are lowered.
-pub(super) fn explicit_super_predicates_of(
-    tcx: TyCtxt<'_>,
+pub(super) fn explicit_super_predicates_of<'tcx>(
+    tcx: TyCtxt<'tcx>,
     trait_def_id: LocalDefId,
-) -> ty::GenericPredicates<'_> {
+) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
     implied_predicates_with_filter(tcx, trait_def_id.to_def_id(), PredicateFilter::SelfOnly)
 }
 
-pub(super) fn explicit_supertraits_containing_assoc_item(
-    tcx: TyCtxt<'_>,
+pub(super) fn explicit_supertraits_containing_assoc_item<'tcx>(
+    tcx: TyCtxt<'tcx>,
     (trait_def_id, assoc_name): (DefId, Ident),
-) -> ty::GenericPredicates<'_> {
+) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
     implied_predicates_with_filter(tcx, trait_def_id, PredicateFilter::SelfThatDefines(assoc_name))
 }
 
-pub(super) fn explicit_implied_predicates_of(
-    tcx: TyCtxt<'_>,
+pub(super) fn explicit_implied_predicates_of<'tcx>(
+    tcx: TyCtxt<'tcx>,
     trait_def_id: LocalDefId,
-) -> ty::GenericPredicates<'_> {
+) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
     implied_predicates_with_filter(
         tcx,
         trait_def_id.to_def_id(),
@@ -612,11 +612,11 @@ pub(super) fn explicit_implied_predicates_of(
 /// Ensures that the super-predicates of the trait with a `DefId`
 /// of `trait_def_id` are lowered and stored. This also ensures that
 /// the transitive super-predicates are lowered.
-pub(super) fn implied_predicates_with_filter(
-    tcx: TyCtxt<'_>,
+pub(super) fn implied_predicates_with_filter<'tcx>(
+    tcx: TyCtxt<'tcx>,
     trait_def_id: DefId,
     filter: PredicateFilter,
-) -> ty::GenericPredicates<'_> {
+) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
     let Some(trait_def_id) = trait_def_id.as_local() else {
         // if `assoc_name` is None, then the query should've been redirected to an
         // external provider
@@ -679,20 +679,16 @@ pub(super) fn implied_predicates_with_filter(
         _ => {}
     }
 
-    ty::GenericPredicates {
-        parent: None,
-        predicates: implied_bounds,
-        effects_min_tys: ty::List::empty(),
-    }
+    ty::EarlyBinder::bind(implied_bounds)
 }
 
 /// Returns the predicates defined on `item_def_id` of the form
 /// `X: Foo` where `X` is the type parameter `def_id`.
 #[instrument(level = "trace", skip(tcx))]
-pub(super) fn type_param_predicates(
-    tcx: TyCtxt<'_>,
+pub(super) fn type_param_predicates<'tcx>(
+    tcx: TyCtxt<'tcx>,
     (item_def_id, def_id, assoc_name): (LocalDefId, LocalDefId, Ident),
-) -> ty::GenericPredicates<'_> {
+) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
     use rustc_hir::*;
     use rustc_middle::ty::Ty;
 
@@ -713,18 +709,20 @@ pub(super) fn type_param_predicates(
         tcx.generics_of(item_def_id).parent.map(|def_id| def_id.expect_local())
     };
 
-    let mut result = parent
-        .map(|parent| {
-            let icx = ItemCtxt::new(tcx, parent);
-            icx.probe_ty_param_bounds(DUMMY_SP, def_id, assoc_name)
-        })
-        .unwrap_or_default();
+    let result = if let Some(parent) = parent {
+        let icx = ItemCtxt::new(tcx, parent);
+        icx.probe_ty_param_bounds(DUMMY_SP, def_id, assoc_name)
+    } else {
+        ty::EarlyBinder::bind(&[] as &[_])
+    };
     let mut extend = None;
 
     let item_hir_id = tcx.local_def_id_to_hir_id(item_def_id);
 
     let hir_node = tcx.hir_node(item_hir_id);
-    let Some(hir_generics) = hir_node.generics() else { return result };
+    let Some(hir_generics) = hir_node.generics() else {
+        return result;
+    };
     if let Node::Item(item) = hir_node
         && let ItemKind::Trait(..) = item.kind
         // Implied `Self: Trait` and supertrait bounds.
@@ -748,9 +746,10 @@ pub(super) fn type_param_predicates(
             _ => false,
         }),
     );
-    result.predicates =
-        tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(extra_predicates));
-    result
+
+    ty::EarlyBinder::bind(
+        tcx.arena.alloc_from_iter(result.skip_binder().iter().copied().chain(extra_predicates)),
+    )
 }
 
 impl<'tcx> ItemCtxt<'tcx> {

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -1761,7 +1761,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                 break Some((bound_vars.into_iter().collect(), assoc_item));
             }
             let predicates = tcx.explicit_supertraits_containing_assoc_item((def_id, assoc_name));
-            let obligations = predicates.predicates.iter().filter_map(|&(pred, _)| {
+            let obligations = predicates.iter_identity_copied().filter_map(|(pred, _)| {
                 let bound_predicate = pred.kind();
                 match bound_predicate.skip_binder() {
                     ty::ClauseKind::Trait(data) => {

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -136,7 +136,7 @@ pub trait HirTyLowerer<'tcx> {
         span: Span,
         def_id: LocalDefId,
         assoc_name: Ident,
-    ) -> ty::GenericPredicates<'tcx>;
+    ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]>;
 
     /// Lower an associated type to a projection.
     ///
@@ -831,13 +831,13 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         debug!(?ty_param_def_id, ?assoc_name, ?span);
         let tcx = self.tcx();
 
-        let predicates = &self.probe_ty_param_bounds(span, ty_param_def_id, assoc_name).predicates;
+        let predicates = &self.probe_ty_param_bounds(span, ty_param_def_id, assoc_name);
         debug!("predicates={:#?}", predicates);
 
         self.probe_single_bound_for_assoc_item(
             || {
                 let trait_refs = predicates
-                    .iter()
+                    .iter_identity_copied()
                     .filter_map(|(p, _)| Some(p.as_trait_clause()?.map_bound(|t| t.trait_ref)));
                 traits::transitive_bounds_that_define_assoc_item(tcx, trait_refs, assoc_name)
             },

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -263,27 +263,24 @@ impl<'tcx> HirTyLowerer<'tcx> for FnCtxt<'_, 'tcx> {
         _: Span,
         def_id: LocalDefId,
         _: Ident,
-    ) -> ty::GenericPredicates<'tcx> {
+    ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
         let tcx = self.tcx;
         let item_def_id = tcx.hir().ty_param_owner(def_id);
         let generics = tcx.generics_of(item_def_id);
         let index = generics.param_def_id_to_index[&def_id.to_def_id()];
         // HACK(eddyb) should get the original `Span`.
         let span = tcx.def_span(def_id);
-        ty::GenericPredicates {
-            parent: None,
-            predicates: tcx.arena.alloc_from_iter(
-                self.param_env.caller_bounds().iter().filter_map(|predicate| {
-                    match predicate.kind().skip_binder() {
-                        ty::ClauseKind::Trait(data) if data.self_ty().is_param(index) => {
-                            Some((predicate, span))
-                        }
-                        _ => None,
+
+        ty::EarlyBinder::bind(tcx.arena.alloc_from_iter(
+            self.param_env.caller_bounds().iter().filter_map(|predicate| {
+                match predicate.kind().skip_binder() {
+                    ty::ClauseKind::Trait(data) if data.self_ty().is_param(index) => {
+                        Some((predicate, span))
                     }
-                }),
-            ),
-            effects_min_tys: ty::List::empty(),
-        }
+                    _ => None,
+                }
+            }),
+        ))
     }
 
     fn lower_assoc_ty(

compiler/rustc_infer/src/traits/util.rs

@@ -123,7 +123,7 @@ pub fn transitive_bounds_that_define_assoc_item<'tcx>(
 
             stack.extend(
                 tcx.explicit_supertraits_containing_assoc_item((trait_ref.def_id(), assoc_name))
-                    .instantiate_own_identity()
+                    .iter_identity_copied()
                     .map(|(clause, _)| clause.instantiate_supertrait(tcx, trait_ref))
                     .filter_map(|clause| clause.as_trait_clause())
                     // FIXME: Negative supertraits are elaborated here lol

compiler/rustc_lint/src/multiple_supertrait_upcastable.rs

@@ -45,8 +45,7 @@ impl<'tcx> LateLintPass<'tcx> for MultipleSupertraitUpcastable {
             let direct_super_traits_iter = cx
                 .tcx
                 .explicit_super_predicates_of(def_id)
-                .predicates
-                .into_iter()
+                .iter_identity_copied()
                 .filter_map(|(pred, _)| pred.as_trait_clause());
             if direct_super_traits_iter.count() > 1 {
                 cx.emit_span_lint(

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -1070,34 +1070,6 @@ impl<'a> CrateMetadataRef<'a> {
         )
     }
 
-    fn get_explicit_item_bounds<'tcx>(
-        self,
-        index: DefIndex,
-        tcx: TyCtxt<'tcx>,
-    ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
-        let lazy = self.root.tables.explicit_item_bounds.get(self, index);
-        let output = if lazy.is_default() {
-            &mut []
-        } else {
-            tcx.arena.alloc_from_iter(lazy.decode((self, tcx)))
-        };
-        ty::EarlyBinder::bind(&*output)
-    }
-
-    fn get_explicit_item_super_predicates<'tcx>(
-        self,
-        index: DefIndex,
-        tcx: TyCtxt<'tcx>,
-    ) -> ty::EarlyBinder<'tcx, &'tcx [(ty::Clause<'tcx>, Span)]> {
-        let lazy = self.root.tables.explicit_item_super_predicates.get(self, index);
-        let output = if lazy.is_default() {
-            &mut []
-        } else {
-            tcx.arena.alloc_from_iter(lazy.decode((self, tcx)))
-        };
-        ty::EarlyBinder::bind(&*output)
-    }
-
     fn get_variant(
         self,
         kind: DefKind,
@@ -1323,10 +1295,6 @@ impl<'a> CrateMetadataRef<'a> {
         self.root.tables.optimized_mir.get(self, id).is_some()
     }
 
-    fn cross_crate_inlinable(self, id: DefIndex) -> bool {
-        self.root.tables.cross_crate_inlinable.get(self, id)
-    }
-
     fn get_fn_has_self_parameter(self, id: DefIndex, sess: &'a Session) -> bool {
         self.root
             .tables