Rollup of 6 pull requests

compiler/rustc_ast_lowering/src/index.rs

@@ -19,7 +19,7 @@ struct NodeCollector<'a, 'hir> {
     parenting: LocalDefIdMap<ItemLocalId>,
 
     /// The parent of this node
-    parent_node: hir::ItemLocalId,
+    parent_node: ItemLocalId,
 
     owner: OwnerId,
 }
@@ -31,17 +31,16 @@ pub(super) fn index_hir<'hir>(
     bodies: &SortedMap<ItemLocalId, &'hir Body<'hir>>,
     num_nodes: usize,
 ) -> (IndexVec<ItemLocalId, ParentedNode<'hir>>, LocalDefIdMap<ItemLocalId>) {
-    let zero_id = ItemLocalId::ZERO;
-    let err_node = ParentedNode { parent: zero_id, node: Node::Err(item.span()) };
+    let err_node = ParentedNode { parent: ItemLocalId::ZERO, node: Node::Err(item.span()) };
     let mut nodes = IndexVec::from_elem_n(err_node, num_nodes);
     // This node's parent should never be accessed: the owner's parent is computed by the
     // hir_owner_parent query. Make it invalid (= ItemLocalId::MAX) to force an ICE whenever it is
     // used.
-    nodes[zero_id] = ParentedNode { parent: ItemLocalId::INVALID, node: item.into() };
+    nodes[ItemLocalId::ZERO] = ParentedNode { parent: ItemLocalId::INVALID, node: item.into() };
     let mut collector = NodeCollector {
         tcx,
         owner: item.def_id(),
-        parent_node: zero_id,
+        parent_node: ItemLocalId::ZERO,
         nodes,
         bodies,
         parenting: Default::default(),
@@ -112,7 +111,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
     }
 
     fn insert_nested(&mut self, item: LocalDefId) {
-        if self.parent_node.as_u32() != 0 {
+        if self.parent_node != ItemLocalId::ZERO {
             self.parenting.insert(item, self.parent_node);
         }
     }

compiler/rustc_feature/src/unstable.rs

@@ -567,6 +567,8 @@ declare_features! (
     (unstable, proc_macro_hygiene, "1.30.0", Some(54727)),
     /// Allows `&raw const $place_expr` and `&raw mut $place_expr` expressions.
     (unstable, raw_ref_op, "1.41.0", Some(64490)),
+    /// Allows `&` and `&mut` patterns to consume match-ergonomics-inserted references.
+    (incomplete, ref_pat_everywhere, "CURRENT_RUSTC_VERSION", Some(123076)),
     /// Allows using the `#[register_tool]` attribute.
     (unstable, register_tool, "1.41.0", Some(66079)),
     /// Allows the `#[repr(i128)]` attribute for enums.

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -461,7 +461,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     where
         T: TypeVisitable<TyCtxt<'tcx>>,
     {
-        t.has_free_regions() || t.has_projections() || t.has_infer_types()
+        t.has_free_regions() || t.has_aliases() || t.has_infer_types()
     }
 
     pub fn node_ty(&self, id: hir::HirId) -> Ty<'tcx> {

compiler/rustc_hir_typeck/src/pat.rs

@@ -130,7 +130,14 @@ enum AdjustMode {
     /// Peel off all immediate reference types.
     Peel,
     /// Reset binding mode to the initial mode.
+    /// Used for destructuring assignment, where we don't want any match ergonomics.
     Reset,
+    /// Produced by ref patterns.
+    /// Reset the binding mode to the initial mode,
+    /// and if the old biding mode was by-reference
+    /// with mutability matching the pattern,
+    /// mark the pattern as having consumed this reference.
+    ResetAndConsumeRef(Mutability),
     /// Pass on the input binding mode and expected type.
     Pass,
 }
@@ -174,7 +181,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             _ => None,
         };
         let adjust_mode = self.calc_adjust_mode(pat, path_res.map(|(res, ..)| res));
-        let (expected, def_bm) = self.calc_default_binding_mode(pat, expected, def_bm, adjust_mode);
+        let (expected, def_bm, ref_pattern_already_consumed) =
+            self.calc_default_binding_mode(pat, expected, def_bm, adjust_mode);
         let pat_info = PatInfo {
             binding_mode: def_bm,
             top_info: ti,
@@ -211,7 +219,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             PatKind::Box(inner) => self.check_pat_box(pat.span, inner, expected, pat_info),
             PatKind::Deref(inner) => self.check_pat_deref(pat.span, inner, expected, pat_info),
-            PatKind::Ref(inner, mutbl) => self.check_pat_ref(pat, inner, mutbl, expected, pat_info),
+            PatKind::Ref(inner, mutbl) => self.check_pat_ref(
+                pat,
+                inner,
+                mutbl,
+                expected,
+                pat_info,
+                ref_pattern_already_consumed,
+            ),
             PatKind::Slice(before, slice, after) => {
                 self.check_pat_slice(pat.span, before, slice, after, expected, pat_info)
             }
@@ -264,17 +279,27 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     /// Compute the new expected type and default binding mode from the old ones
     /// as well as the pattern form we are currently checking.
+    ///
+    /// Last entry is only relevant for ref patterns (`&` and `&mut`);
+    /// if `true`, then the ref pattern consumed a match ergonomics inserted reference
+    /// and so does no need to match against a reference in the scrutinee type.
     fn calc_default_binding_mode(
         &self,
         pat: &'tcx Pat<'tcx>,
         expected: Ty<'tcx>,
         def_bm: BindingAnnotation,
         adjust_mode: AdjustMode,
-    ) -> (Ty<'tcx>, BindingAnnotation) {
+    ) -> (Ty<'tcx>, BindingAnnotation, bool) {
         match adjust_mode {
-            AdjustMode::Pass => (expected, def_bm),
-            AdjustMode::Reset => (expected, INITIAL_BM),
-            AdjustMode::Peel => self.peel_off_references(pat, expected, def_bm),
+            AdjustMode::Pass => (expected, def_bm, false),
+            AdjustMode::Reset => (expected, INITIAL_BM, false),
+            AdjustMode::ResetAndConsumeRef(mutbl) => {
+                (expected, INITIAL_BM, def_bm.0 == ByRef::Yes(mutbl))
+            }
+            AdjustMode::Peel => {
+                let peeled = self.peel_off_references(pat, expected, def_bm);
+                (peeled.0, peeled.1, false)
+            }
         }
     }
 
@@ -329,7 +354,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // ```
             //
             // See issue #46688.
-            PatKind::Ref(..) => AdjustMode::Reset,
+            PatKind::Ref(_, mutbl) => AdjustMode::ResetAndConsumeRef(*mutbl),
             // A `_` pattern works with any expected type, so there's no need to do anything.
             PatKind::Wild
             // A malformed pattern doesn't have an expected type, so let's just accept any type.
@@ -840,8 +865,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             && let Some(mt) = self.shallow_resolve(expected).builtin_deref(true)
             && let ty::Dynamic(..) = mt.ty.kind()
         {
-            // This is "x = SomeTrait" being reduced from
-            // "let &x = &SomeTrait" or "let box x = Box<SomeTrait>", an error.
+            // This is "x = dyn SomeTrait" being reduced from
+            // "let &x = &dyn SomeTrait" or "let box x = Box<dyn SomeTrait>", an error.
             let type_str = self.ty_to_string(expected);
             let mut err = struct_span_code_err!(
                 self.dcx(),
@@ -2036,6 +2061,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         mutbl: Mutability,
         expected: Ty<'tcx>,
         pat_info: PatInfo<'tcx, '_>,
+        consumed_inherited_ref: bool,
     ) -> Ty<'tcx> {
         let tcx = self.tcx;
         let expected = self.shallow_resolve(expected);
@@ -2051,26 +2077,37 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 match *expected.kind() {
                     ty::Ref(_, r_ty, r_mutbl) if r_mutbl == mutbl => (expected, r_ty),
                     _ => {
-                        let inner_ty = self.next_ty_var(TypeVariableOrigin {
-                            kind: TypeVariableOriginKind::TypeInference,
-                            span: inner.span,
-                        });
-                        let ref_ty = self.new_ref_ty(pat.span, mutbl, inner_ty);
-                        debug!("check_pat_ref: demanding {:?} = {:?}", expected, ref_ty);
-                        let err = self.demand_eqtype_pat_diag(
-                            pat.span,
-                            expected,
-                            ref_ty,
-                            pat_info.top_info,
-                        );
+                        if consumed_inherited_ref && self.tcx.features().ref_pat_everywhere {
+                            // We already matched against a match-ergonmics inserted reference,
+                            // so we don't need to match against a reference from the original type.
+                            // Save this infor for use in lowering later
+                            self.typeck_results
+                                .borrow_mut()
+                                .skipped_ref_pats_mut()
+                                .insert(pat.hir_id);
+                            (expected, expected)
+                        } else {
+                            let inner_ty = self.next_ty_var(TypeVariableOrigin {
+                                kind: TypeVariableOriginKind::TypeInference,
+                                span: inner.span,
+                            });
+                            let ref_ty = self.new_ref_ty(pat.span, mutbl, inner_ty);
+                            debug!("check_pat_ref: demanding {:?} = {:?}", expected, ref_ty);
+                            let err = self.demand_eqtype_pat_diag(
+                                pat.span,
+                                expected,
+                                ref_ty,
+                                pat_info.top_info,
+                            );
 
-                        // Look for a case like `fn foo(&foo: u32)` and suggest
-                        // `fn foo(foo: &u32)`
-                        if let Some(mut err) = err {
-                            self.borrow_pat_suggestion(&mut err, pat);
-                            err.emit();
+                            // Look for a case like `fn foo(&foo: u32)` and suggest
+                            // `fn foo(foo: &u32)`
+                            if let Some(mut err) = err {
+                                self.borrow_pat_suggestion(&mut err, pat);
+                                err.emit();
+                            }
+                            (ref_ty, inner_ty)
                         }
-                        (ref_ty, inner_ty)
                     }
                 }
             }

compiler/rustc_hir_typeck/src/writeback.rs

@@ -345,6 +345,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for WritebackCx<'cx, 'tcx> {
             _ => {}
         };
 
+        self.visit_skipped_ref_pats(p.hir_id);
         self.visit_pat_adjustments(p.span, p.hir_id);
 
         self.visit_node_id(p.span, p.hir_id);
@@ -674,6 +675,14 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         }
     }
 
+    #[instrument(skip(self), level = "debug")]
+    fn visit_skipped_ref_pats(&mut self, hir_id: hir::HirId) {
+        if self.fcx.typeck_results.borrow_mut().skipped_ref_pats_mut().remove(hir_id) {
+            debug!("node is a skipped ref pat");
+            self.typeck_results.skipped_ref_pats_mut().insert(hir_id);
+        }
+    }
+
     fn visit_liberated_fn_sigs(&mut self) {
         let fcx_typeck_results = self.fcx.typeck_results.borrow();
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);

compiler/rustc_middle/src/hir/mod.rs

@@ -179,7 +179,7 @@ pub fn provide(providers: &mut Providers) {
                     .parenting
                     .get(&owner_id.def_id)
                     .copied()
-                    .unwrap_or(ItemLocalId::from_u32(0)),
+                    .unwrap_or(ItemLocalId::ZERO),
             }
         })
     };

compiler/rustc_middle/src/traits/solve/inspect.rs

@@ -121,8 +121,6 @@ pub enum ProbeStep<'tcx> {
     /// used whenever there are multiple candidates to prove the
     /// current goalby .
     NestedProbe(Probe<'tcx>),
-    CommitIfOkStart,
-    CommitIfOkSuccess,
 }
 
 /// What kind of probe we're in. In case the probe represents a candidate, or
@@ -132,6 +130,8 @@ pub enum ProbeStep<'tcx> {
 pub enum ProbeKind<'tcx> {
     /// The root inference context while proving a goal.
     Root { result: QueryResult<'tcx> },
+    /// Trying to normalize an alias by at least one stpe in `NormalizesTo`.
+    TryNormalizeNonRigid { result: QueryResult<'tcx> },
     /// Probe entered when normalizing the self ty during candidate assembly
     NormalizedSelfTyAssembly,
     /// Some candidate to prove the current goal.
@@ -143,9 +143,6 @@ pub enum ProbeKind<'tcx> {
     /// Used in the probe that wraps normalizing the non-self type for the unsize
     /// trait, which is also structurally matched on.
     UnsizeAssembly,
-    /// A call to `EvalCtxt::commit_if_ok` which failed, causing the work
-    /// to be discarded.
-    CommitIfOk,
     /// During upcasting from some source object to target object type, used to
     /// do a probe to find out what projection type(s) may be used to prove that
     /// the source type upholds all of the target type's object bounds.

compiler/rustc_middle/src/traits/solve/inspect/format.rs

@@ -100,6 +100,9 @@ impl<'a, 'b> ProofTreeFormatter<'a, 'b> {
             ProbeKind::Root { result } => {
                 write!(self.f, "ROOT RESULT: {result:?}")
             }
+            ProbeKind::TryNormalizeNonRigid { result } => {
+                write!(self.f, "TRY NORMALIZE NON-RIGID: {result:?}")
+            }
             ProbeKind::NormalizedSelfTyAssembly => {
                 write!(self.f, "NORMALIZING SELF TY FOR ASSEMBLY:")
             }
@@ -109,9 +112,6 @@ impl<'a, 'b> ProofTreeFormatter<'a, 'b> {
             ProbeKind::UpcastProjectionCompatibility => {
                 write!(self.f, "PROBING FOR PROJECTION COMPATIBILITY FOR UPCASTING:")
             }
-            ProbeKind::CommitIfOk => {
-                write!(self.f, "COMMIT_IF_OK:")
-            }
             ProbeKind::MiscCandidate { name, result } => {
                 write!(self.f, "CANDIDATE {name}: {result:?}")
             }
@@ -132,8 +132,6 @@ impl<'a, 'b> ProofTreeFormatter<'a, 'b> {
                     }
                     ProbeStep::EvaluateGoals(eval) => this.format_added_goals_evaluation(eval)?,
                     ProbeStep::NestedProbe(probe) => this.format_probe(probe)?,
-                    ProbeStep::CommitIfOkStart => writeln!(this.f, "COMMIT_IF_OK START")?,
-                    ProbeStep::CommitIfOkSuccess => writeln!(this.f, "COMMIT_IF_OK SUCCESS")?,
                 }
             }
             Ok(())

compiler/rustc_middle/src/ty/normalize_erasing_regions.rs

@@ -49,7 +49,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let value = self.erase_regions(value);
         debug!(?value);
 
-        if !value.has_projections() {
+        if !value.has_aliases() {
             value
         } else {
             value.fold_with(&mut NormalizeAfterErasingRegionsFolder { tcx: self, param_env })
@@ -81,7 +81,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let value = self.erase_regions(value);
         debug!(?value);
 
-        if !value.has_projections() {
+        if !value.has_aliases() {
             Ok(value)
         } else {
             let mut folder = TryNormalizeAfterErasingRegionsFolder::new(self, param_env);