Rollup merge of rust-lang#120872 - petrochenkov:opthirpar, r=cjgillot

hir: Refactor getters for HIR parents

See individual commits.

I ended up removing on of the FIXMEs from rust-lang#120206 instead of addressing it.

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -403,8 +403,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     }
                 }
                 let typeck = self.infcx.tcx.typeck(self.mir_def_id());
-                let hir_id = hir.parent_id(expr.hir_id);
-                let parent = self.infcx.tcx.hir_node(hir_id);
+                let parent = self.infcx.tcx.parent_hir_node(expr.hir_id);
                 let (def_id, args, offset) = if let hir::Node::Expr(parent_expr) = parent
                     && let hir::ExprKind::MethodCall(_, _, args, _) = parent_expr.kind
                     && let Some(def_id) = typeck.type_dependent_def_id(parent_expr.hir_id)
@@ -1660,8 +1659,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
         // Check that the parent of the closure is a method call,
         // with receiver matching with local's type (modulo refs)
-        let parent = hir.parent_id(closure_expr.hir_id);
-        if let hir::Node::Expr(parent) = tcx.hir_node(parent) {
+        if let hir::Node::Expr(parent) = tcx.parent_hir_node(closure_expr.hir_id) {
             if let hir::ExprKind::MethodCall(_, recv, ..) = parent.kind {
                 let recv_ty = typeck_results.expr_ty(recv);
 

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -944,7 +944,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let hir = self.infcx.tcx.hir();
         let closure_id = self.mir_hir_id();
         let closure_span = self.infcx.tcx.def_span(self.mir_def_id());
-        let fn_call_id = hir.parent_id(closure_id);
+        let fn_call_id = self.infcx.tcx.parent_hir_id(closure_id);
         let node = self.infcx.tcx.hir_node(fn_call_id);
         let def_id = hir.enclosing_body_owner(fn_call_id);
         let mut look_at_return = true;
@@ -1034,7 +1034,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         if let InstanceDef::Item(def_id) = source.instance
             && let Some(Node::Expr(hir::Expr { hir_id, kind, .. })) = hir.get_if_local(def_id)
             && let ExprKind::Closure(hir::Closure { kind: hir::ClosureKind::Closure, .. }) = kind
-            && let Some(Node::Expr(expr)) = hir.find_parent(*hir_id)
+            && let Node::Expr(expr) = self.infcx.tcx.parent_hir_node(*hir_id)
         {
             let mut cur_expr = expr;
             while let ExprKind::MethodCall(path_segment, recv, _, _) = cur_expr.kind {

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -214,8 +214,11 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 if let Some(id) = placeholder.bound.kind.get_id()
                     && let Some(placeholder_id) = id.as_local()
                     && let gat_hir_id = self.infcx.tcx.local_def_id_to_hir_id(placeholder_id)
-                    && let Some(generics_impl) =
-                        hir.get_parent(hir.parent_id(gat_hir_id)).generics()
+                    && let Some(generics_impl) = self
+                        .infcx
+                        .tcx
+                        .parent_hir_node(self.infcx.tcx.parent_hir_id(gat_hir_id))
+                        .generics()
                 {
                     Some((gat_hir_id, generics_impl))
                 } else {

compiler/rustc_const_eval/src/transform/check_consts/mod.rs

@@ -131,11 +131,10 @@ fn is_parent_const_stable_trait(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     let local_def_id = def_id.expect_local();
     let hir_id = tcx.local_def_id_to_hir_id(local_def_id);
 
-    let Some(parent) = tcx.hir().opt_parent_id(hir_id) else { return false };
-
-    if !tcx.is_const_trait_impl_raw(parent.owner.def_id.to_def_id()) {
+    let parent_owner_id = tcx.parent_hir_id(hir_id).owner;
+    if !tcx.is_const_trait_impl_raw(parent_owner_id.to_def_id()) {
         return false;
     }
 
-    tcx.lookup_const_stability(parent.owner).is_some_and(|stab| stab.is_const_stable())
+    tcx.lookup_const_stability(parent_owner_id).is_some_and(|stab| stab.is_const_stable())
 }

compiler/rustc_hir/src/hir.rs

@@ -3508,7 +3508,7 @@ impl<'hir> Node<'hir> {
     /// ```ignore (illustrative)
     /// ctor
     ///     .ctor_hir_id()
-    ///     .and_then(|ctor_id| tcx.hir().find_parent(ctor_id))
+    ///     .map(|ctor_id| tcx.parent_hir_node(ctor_id))
     ///     .and_then(|parent| parent.ident())
     /// ```
     pub fn ident(&self) -> Option<Ident> {

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2749,14 +2749,12 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         arg_idx: Option<usize>,
     ) -> Option<Ty<'tcx>> {
         let tcx = self.tcx();
-        let hir = tcx.hir();
-
         let hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), ident, .. }) =
             tcx.hir_node(fn_hir_id)
         else {
             return None;
         };
-        let i = hir.get_parent(fn_hir_id).expect_item().expect_impl();
+        let i = tcx.parent_hir_node(fn_hir_id).expect_item().expect_impl();
 
         let trait_ref =
             self.instantiate_mono_trait_ref(i.of_trait.as_ref()?, self.ast_ty_to_ty(i.self_ty));

compiler/rustc_hir_analysis/src/collect.rs

@@ -224,11 +224,8 @@ pub(crate) fn placeholder_type_error_diag<'tcx>(
             is_fn = true;
 
             // Check if parent is const or static
-            let parent_id = tcx.hir().parent_id(hir_ty.hir_id);
-            let parent_node = tcx.hir_node(parent_id);
-
             is_const_or_static = matches!(
-                parent_node,
+                tcx.parent_hir_node(hir_ty.hir_id),
                 Node::Item(&hir::Item {
                     kind: hir::ItemKind::Const(..) | hir::ItemKind::Static(..),
                     ..
@@ -1085,7 +1082,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<ty::PolyFnSig<
 
         ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), generics, .. }) => {
             // Do not try to infer the return type for a impl method coming from a trait
-            if let Item(hir::Item { kind: ItemKind::Impl(i), .. }) = tcx.hir().get_parent(hir_id)
+            if let Item(hir::Item { kind: ItemKind::Impl(i), .. }) = tcx.parent_hir_node(hir_id)
                 && i.of_trait.is_some()
             {
                 icx.astconv().ty_of_fn(

compiler/rustc_hir_analysis/src/collect/generics_of.rs

@@ -51,7 +51,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
                 // of a const parameter type, e.g. `struct Foo<const N: usize, const M: [u8; N]>` is not allowed.
                 None
             } else if tcx.features().generic_const_exprs {
-                let parent_node = tcx.hir().get_parent(hir_id);
+                let parent_node = tcx.parent_hir_node(hir_id);
                 if let Node::Variant(Variant { disr_expr: Some(constant), .. }) = parent_node
                     && constant.hir_id == hir_id
                 {
@@ -113,7 +113,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
                     Some(parent_def_id.to_def_id())
                 }
             } else {
-                let parent_node = tcx.hir().get_parent(hir_id);
+                let parent_node = tcx.parent_hir_node(hir_id);
                 match parent_node {
                     // HACK(eddyb) this provides the correct generics for repeat
                     // expressions' count (i.e. `N` in `[x; N]`), and explicit

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -315,8 +315,7 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen
     // We create bi-directional Outlives predicates between the original
     // and the duplicated parameter, to ensure that they do not get out of sync.
     if let Node::Item(&Item { kind: ItemKind::OpaqueTy(..), .. }) = node {
-        let opaque_ty_id = tcx.hir().parent_id(hir_id);
-        let opaque_ty_node = tcx.hir_node(opaque_ty_id);
+        let opaque_ty_node = tcx.parent_hir_node(hir_id);
         let Node::Ty(&Ty { kind: TyKind::OpaqueDef(_, lifetimes, _), .. }) = opaque_ty_node else {
             bug!("unexpected {opaque_ty_node:?}")
         };

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -732,7 +732,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                     let Some(def_id) = def_id.as_local() else { continue };
                     let hir_id = self.tcx.local_def_id_to_hir_id(def_id);
                     // Ensure that the parent of the def is an item, not HRTB
-                    let parent_id = self.tcx.hir().parent_id(hir_id);
+                    let parent_id = self.tcx.parent_hir_id(hir_id);
                     if !parent_id.is_owner() {
                         struct_span_code_err!(
                             self.tcx.dcx(),

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -30,7 +30,7 @@ fn anon_const_type_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Ty<'tcx> {
         );
     };
 
-    let parent_node_id = tcx.hir().parent_id(hir_id);
+    let parent_node_id = tcx.parent_hir_id(hir_id);
     let parent_node = tcx.hir_node(parent_node_id);
 
     let (generics, arg_idx) = match parent_node {
@@ -79,7 +79,7 @@ fn anon_const_type_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Ty<'tcx> {
         }
 
         Node::TypeBinding(binding @ &TypeBinding { hir_id: binding_id, .. })
-            if let Node::TraitRef(trait_ref) = tcx.hir_node(tcx.hir().parent_id(binding_id)) =>
+            if let Node::TraitRef(trait_ref) = tcx.parent_hir_node(binding_id) =>
         {
             let Some(trait_def_id) = trait_ref.trait_def_id() else {
                 return Ty::new_error_with_message(

compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs

@@ -135,7 +135,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
             // Here we check if the reference to the generic type
             // is from the 'of_trait' field of the enclosing impl
 
-            let parent = self.tcx.hir().get_parent(self.path_segment.hir_id);
+            let parent = self.tcx.parent_hir_node(self.path_segment.hir_id);
             let parent_item = self.tcx.hir_node_by_def_id(
                 self.tcx.hir().get_parent_item(self.path_segment.hir_id).def_id,
             );
@@ -770,9 +770,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
             num = num_trait_generics_except_self,
         );
 
-        if let Some(parent_node) = self.tcx.hir().opt_parent_id(self.path_segment.hir_id)
-            && let hir::Node::Expr(expr) = self.tcx.hir_node(parent_node)
-        {
+        if let hir::Node::Expr(expr) = self.tcx.parent_hir_node(self.path_segment.hir_id) {
             match &expr.kind {
                 hir::ExprKind::Path(qpath) => self
                     .suggest_moving_args_from_assoc_fn_to_trait_for_qualified_path(

compiler/rustc_hir_typeck/src/_match.rs

@@ -287,7 +287,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     {
         // If this `if` expr is the parent's function return expr,
         // the cause of the type coercion is the return type, point at it. (#25228)
-        let hir_id = self.tcx.hir().parent_id(self.tcx.hir().parent_id(then_expr.hir_id));
+        let hir_id = self.tcx.parent_hir_id(self.tcx.parent_hir_id(then_expr.hir_id));
         let ret_reason = self.maybe_get_coercion_reason(hir_id, if_span);
         let cause = self.cause(if_span, ObligationCauseCode::IfExpressionWithNoElse);
         let mut error = false;
@@ -396,7 +396,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let node = self.tcx.hir_node(hir_id);
         if let hir::Node::Block(block) = node {
             // check that the body's parent is an fn
-            let parent = self.tcx.hir().get_parent(self.tcx.hir().parent_id(block.hir_id));
+            let parent = self.tcx.parent_hir_node(self.tcx.parent_hir_id(block.hir_id));
             if let (Some(expr), hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(..), .. })) =
                 (&block.expr, parent)
             {

compiler/rustc_hir_typeck/src/callee.rs

@@ -361,7 +361,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let fn_decl_span = if let hir::Node::Expr(hir::Expr {
             kind: hir::ExprKind::Closure(&hir::Closure { fn_decl_span, .. }),
             ..
-        }) = hir.get_parent(hir_id)
+        }) = self.tcx.parent_hir_node(hir_id)
         {
             fn_decl_span
         } else if let Some((
@@ -383,11 +383,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         {
             // Actually need to unwrap one more layer of HIR to get to
             // the _real_ closure...
-            let async_closure = hir.parent_id(parent_hir_id);
             if let hir::Node::Expr(hir::Expr {
                 kind: hir::ExprKind::Closure(&hir::Closure { fn_decl_span, .. }),
                 ..
-            }) = self.tcx.hir_node(async_closure)
+            }) = self.tcx.parent_hir_node(parent_hir_id)
             {
                 fn_decl_span
             } else {
@@ -415,8 +414,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         call_expr: &'tcx hir::Expr<'tcx>,
         callee_expr: &'tcx hir::Expr<'tcx>,
     ) -> bool {
-        let hir_id = self.tcx.hir().parent_id(call_expr.hir_id);
-        let parent_node = self.tcx.hir_node(hir_id);
+        let parent_node = self.tcx.parent_hir_node(call_expr.hir_id);
         if let (
             hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Array(_), .. }),
             hir::ExprKind::Tup(exp),

compiler/rustc_hir_typeck/src/coercion.rs

@@ -1594,7 +1594,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
                         err.span_label(cause.span, "return type is not `()`");
                     }
                     ObligationCauseCode::BlockTailExpression(blk_id, ..) => {
-                        let parent_id = fcx.tcx.hir().parent_id(blk_id);
+                        let parent_id = fcx.tcx.parent_hir_id(blk_id);
                         err = self.report_return_mismatched_types(
                             cause,
                             expected,
@@ -1785,7 +1785,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
     ) -> DiagnosticBuilder<'a> {
         let mut err = fcx.err_ctxt().report_mismatched_types(cause, expected, found, ty_err);
 
-        let parent_id = fcx.tcx.hir().parent_id(id);
+        let parent_id = fcx.tcx.parent_hir_id(id);
         let parent = fcx.tcx.hir_node(parent_id);
         if let Some(expr) = expression
             && let hir::Node::Expr(hir::Expr {

compiler/rustc_hir_typeck/src/demand.rs

@@ -298,7 +298,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let hir::Node::Pat(pat) = self.tcx.hir_node(local_hir_id) else {
             return false;
         };
-        let (init_ty_hir_id, init) = match hir.get_parent(pat.hir_id) {
+        let (init_ty_hir_id, init) = match self.tcx.parent_hir_node(pat.hir_id) {
             hir::Node::Local(hir::Local { ty: Some(ty), init, .. }) => (ty.hir_id, *init),
             hir::Node::Local(hir::Local { init: Some(init), .. }) => (init.hir_id, Some(*init)),
             _ => return false,
@@ -445,7 +445,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 continue;
             }
 
-            if let hir::Node::Expr(parent_expr) = hir.get_parent(binding.hir_id)
+            if let hir::Node::Expr(parent_expr) = self.tcx.parent_hir_node(binding.hir_id)
                 && let hir::ExprKind::MethodCall(segment, rcvr, args, _) = parent_expr.kind
                 && rcvr.hir_id == binding.hir_id
             {
@@ -557,7 +557,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let Some(TypeError::Sorts(ExpectedFound { expected, .. })) = error else {
             return;
         };
-        let mut parent_id = self.tcx.hir().parent_id(expr.hir_id);
+        let mut parent_id = self.tcx.parent_hir_id(expr.hir_id);
         let mut parent;
         'outer: loop {
             // Climb the HIR tree to see if the current `Expr` is part of a `break;` statement.
@@ -568,7 +568,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 break;
             };
             parent = p;
-            parent_id = self.tcx.hir().parent_id(parent_id);
+            parent_id = self.tcx.parent_hir_id(parent_id);
             let hir::ExprKind::Break(destination, _) = parent.kind else {
                 continue;
             };
@@ -578,19 +578,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // Climb the HIR tree to find the (desugared) `loop` this `break` corresponds to.
                 let parent = match self.tcx.hir_node(parent_id) {
                     hir::Node::Expr(&ref parent) => {
-                        parent_id = self.tcx.hir().parent_id(parent.hir_id);
+                        parent_id = self.tcx.parent_hir_id(parent.hir_id);
                         parent
                     }
                     hir::Node::Stmt(hir::Stmt {
                         hir_id,
                         kind: hir::StmtKind::Semi(&ref parent) | hir::StmtKind::Expr(&ref parent),
                         ..
                     }) => {
-                        parent_id = self.tcx.hir().parent_id(*hir_id);
+                        parent_id = self.tcx.parent_hir_id(*hir_id);
                         parent
                     }
                     hir::Node::Block(_) => {
-                        parent_id = self.tcx.hir().parent_id(parent_id);
+                        parent_id = self.tcx.parent_hir_id(parent_id);
                         parent
                     }
                     _ => break,
@@ -677,8 +677,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expr: &hir::Expr<'_>,
         error: Option<TypeError<'tcx>>,
     ) {
-        let parent = self.tcx.hir().parent_id(expr.hir_id);
-        match (self.tcx.hir_node(parent), error) {
+        match (self.tcx.parent_hir_node(expr.hir_id), error) {
             (hir::Node::Local(hir::Local { ty: Some(ty), init: Some(init), .. }), _)
                 if init.hir_id == expr.hir_id =>
             {
@@ -724,16 +723,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         if let hir::Node::Pat(pat) = self.tcx.hir_node(*hir_id) {
                             primary_span = pat.span;
                             secondary_span = pat.span;
-                            match self.tcx.hir().find_parent(pat.hir_id) {
-                                Some(hir::Node::Local(hir::Local { ty: Some(ty), .. })) => {
+                            match self.tcx.parent_hir_node(pat.hir_id) {
+                                hir::Node::Local(hir::Local { ty: Some(ty), .. }) => {
                                     primary_span = ty.span;
                                     post_message = " type";
                                 }
-                                Some(hir::Node::Local(hir::Local { init: Some(init), .. })) => {
+                                hir::Node::Local(hir::Local { init: Some(init), .. }) => {
                                     primary_span = init.span;
                                     post_message = " value";
                                 }
-                                Some(hir::Node::Param(hir::Param { ty_span, .. })) => {
+                                hir::Node::Param(hir::Param { ty_span, .. }) => {
                                     primary_span = *ty_span;
                                     post_message = " parameter type";
                                 }
@@ -787,12 +786,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expr: &hir::Expr<'_>,
         error: Option<TypeError<'tcx>>,
     ) {
-        let parent = self.tcx.hir().parent_id(expr.hir_id);
         let Some(TypeError::Sorts(ExpectedFound { expected, .. })) = error else {
             return;
         };
         let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Assign(lhs, rhs, _), .. }) =
-            self.tcx.hir_node(parent)
+            self.tcx.parent_hir_node(expr.hir_id)
         else {
             return;
         };
@@ -1017,7 +1015,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         )) = expr.kind
         {
             let bind = self.tcx.hir_node(*bind_hir_id);
-            let parent = self.tcx.hir_node(self.tcx.hir().parent_id(*bind_hir_id));
+            let parent = self.tcx.parent_hir_node(*bind_hir_id);
             if let hir::Node::Pat(hir::Pat {
                 kind: hir::PatKind::Binding(_, _hir_id, _, _), ..
             }) = bind
@@ -1088,7 +1086,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expr: &hir::Expr<'_>,
         checked_ty: Ty<'tcx>,
     ) {
-        let Some(hir::Node::Expr(parent_expr)) = self.tcx.hir().find_parent(expr.hir_id) else {
+        let hir::Node::Expr(parent_expr) = self.tcx.parent_hir_node(expr.hir_id) else {
             return;
         };
         enum CallableKind {