Auto merge of #120206 - petrochenkov:somehir, r=<try>

hir: Make sure all `HirId`s have corresponding HIR `Node`s

And then remove `tcx.opt_hir_node(hir_id)` in favor of `tcx.hir_node(hir_id)`.

compiler/rustc_ast_lowering/src/index.rs

@@ -29,7 +29,7 @@ pub(super) fn index_hir<'hir>(
     tcx: TyCtxt<'hir>,
     item: hir::OwnerNode<'hir>,
     bodies: &SortedMap<ItemLocalId, &'hir Body<'hir>>,
-) -> (IndexVec<ItemLocalId, Option<ParentedNode<'hir>>>, LocalDefIdMap<ItemLocalId>) {
+) -> (IndexVec<ItemLocalId, ParentedNode<'hir>>, LocalDefIdMap<ItemLocalId>) {
     let mut nodes = IndexVec::new();
     // 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
@@ -54,7 +54,18 @@ pub(super) fn index_hir<'hir>(
         OwnerNode::ForeignItem(item) => collector.visit_foreign_item(item),
     };
 
-    (collector.nodes, collector.parenting)
+    let err = || {
+        let span = item.span();
+        tcx.dcx().span_delayed_bug(*span, "ID not encountered when visiting item HIR");
+        ParentedNode { parent: ItemLocalId::new(0), node: Node::Err(span) }
+    };
+    let nodes = collector
+        .nodes
+        .into_iter()
+        .map(|parented_node| parented_node.unwrap_or_else(err))
+        .collect();
+
+    (nodes, collector.parenting)
 }
 
 impl<'a, 'hir> NodeCollector<'a, 'hir> {
@@ -348,4 +359,28 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
 
         self.visit_nested_foreign_item(id);
     }
+
+    fn visit_where_predicate(&mut self, predicate: &'hir WherePredicate<'hir>) {
+        match predicate {
+            WherePredicate::BoundPredicate(pred) => {
+                self.insert(pred.span, pred.hir_id, Node::WhereBoundPredicate(pred));
+                self.with_parent(pred.hir_id, |this| {
+                    intravisit::walk_where_predicate(this, predicate)
+                })
+            }
+            _ => intravisit::walk_where_predicate(self, predicate),
+        }
+    }
+
+    fn visit_let_expr(&mut self, lex: &'hir Let<'hir>) {
+        self.insert(lex.span, lex.hir_id, Node::Let(lex));
+        self.with_parent(lex.hir_id, |this| intravisit::walk_let_expr(this, lex))
+    }
+
+    fn visit_array_length(&mut self, len: &'hir ArrayLen) {
+        match len {
+            ArrayLen::Infer(hir_id, span) => self.insert(*span, *hir_id, Node::ArrayLenInfer(span)),
+            ArrayLen::Body(..) => intravisit::walk_array_len(self, len),
+        }
+    }
 }

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -399,66 +399,60 @@ 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);
-                if let Some(parent) = self.infcx.tcx.opt_hir_node(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)
-                    {
-                        (def_id.as_local(), args, 1)
-                    } else if let hir::Node::Expr(parent_expr) = parent
-                        && let hir::ExprKind::Call(call, args) = parent_expr.kind
-                        && let ty::FnDef(def_id, _) = typeck.node_type(call.hir_id).kind()
-                    {
-                        (def_id.as_local(), args, 0)
-                    } else {
-                        (None, &[][..], 0)
+                let parent = self.infcx.tcx.hir_node(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)
+                {
+                    (def_id.as_local(), args, 1)
+                } else if let hir::Node::Expr(parent_expr) = parent
+                    && let hir::ExprKind::Call(call, args) = parent_expr.kind
+                    && let ty::FnDef(def_id, _) = typeck.node_type(call.hir_id).kind()
+                {
+                    (def_id.as_local(), args, 0)
+                } else {
+                    (None, &[][..], 0)
+                };
+                if let Some(def_id) = def_id
+                    && let node =
+                        self.infcx.tcx.hir_node(self.infcx.tcx.local_def_id_to_hir_id(def_id))
+                    && let Some(fn_sig) = node.fn_sig()
+                    && let Some(ident) = node.ident()
+                    && let Some(pos) = args.iter().position(|arg| arg.hir_id == expr.hir_id)
+                    && let Some(arg) = fn_sig.decl.inputs.get(pos + offset)
+                {
+                    let mut span: MultiSpan = arg.span.into();
+                    span.push_span_label(
+                        arg.span,
+                        "this parameter takes ownership of the value".to_string(),
+                    );
+                    let descr = match node.fn_kind() {
+                        Some(hir::intravisit::FnKind::ItemFn(..)) | None => "function",
+                        Some(hir::intravisit::FnKind::Method(..)) => "method",
+                        Some(hir::intravisit::FnKind::Closure) => "closure",
                     };
-                    if let Some(def_id) = def_id
-                        && let Some(node) = self
-                            .infcx
-                            .tcx
-                            .opt_hir_node(self.infcx.tcx.local_def_id_to_hir_id(def_id))
-                        && let Some(fn_sig) = node.fn_sig()
-                        && let Some(ident) = node.ident()
-                        && let Some(pos) = args.iter().position(|arg| arg.hir_id == expr.hir_id)
-                        && let Some(arg) = fn_sig.decl.inputs.get(pos + offset)
-                    {
-                        let mut span: MultiSpan = arg.span.into();
-                        span.push_span_label(
-                            arg.span,
-                            "this parameter takes ownership of the value".to_string(),
-                        );
-                        let descr = match node.fn_kind() {
-                            Some(hir::intravisit::FnKind::ItemFn(..)) | None => "function",
-                            Some(hir::intravisit::FnKind::Method(..)) => "method",
-                            Some(hir::intravisit::FnKind::Closure) => "closure",
-                        };
-                        span.push_span_label(ident.span, format!("in this {descr}"));
-                        err.span_note(
-                            span,
-                            format!(
-                                "consider changing this parameter type in {descr} `{ident}` to \
+                    span.push_span_label(ident.span, format!("in this {descr}"));
+                    err.span_note(
+                        span,
+                        format!(
+                            "consider changing this parameter type in {descr} `{ident}` to \
                                  borrow instead if owning the value isn't necessary",
-                            ),
-                        );
-                    }
-                    let place = &self.move_data.move_paths[mpi].place;
-                    let ty = place.ty(self.body, self.infcx.tcx).ty;
-                    if let hir::Node::Expr(parent_expr) = parent
-                        && let hir::ExprKind::Call(call_expr, _) = parent_expr.kind
-                        && let hir::ExprKind::Path(hir::QPath::LangItem(
-                            LangItem::IntoIterIntoIter,
-                            _,
-                        )) = call_expr.kind
-                    {
-                        // Do not suggest `.clone()` in a `for` loop, we already suggest borrowing.
-                    } else if let UseSpans::FnSelfUse { kind: CallKind::Normal { .. }, .. } =
-                        move_spans
-                    {
-                        // We already suggest cloning for these cases in `explain_captures`.
-                    } else {
-                        self.suggest_cloning(err, ty, expr, move_span);
-                    }
+                        ),
+                    );
+                }
+                let place = &self.move_data.move_paths[mpi].place;
+                let ty = place.ty(self.body, self.infcx.tcx).ty;
+                if let hir::Node::Expr(parent_expr) = parent
+                    && let hir::ExprKind::Call(call_expr, _) = parent_expr.kind
+                    && let hir::ExprKind::Path(hir::QPath::LangItem(LangItem::IntoIterIntoIter, _)) =
+                        call_expr.kind
+                {
+                    // Do not suggest `.clone()` in a `for` loop, we already suggest borrowing.
+                } else if let UseSpans::FnSelfUse { kind: CallKind::Normal { .. }, .. } = move_spans
+                {
+                    // We already suggest cloning for these cases in `explain_captures`.
+                } else {
+                    self.suggest_cloning(err, ty, expr, move_span);
                 }
             }
             if let Some(pat) = finder.pat {
@@ -1757,7 +1751,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         fn_decl: hir::FnDecl { inputs, .. },
                         ..
                     }) = e.kind
-                        && let Some(hir::Node::Expr(body)) = self.tcx.opt_hir_node(body.hir_id)
+                        && let hir::Node::Expr(body) = self.tcx.hir_node(body.hir_id)
                     {
                         self.suggest_arg = "this: &Self".to_string();
                         if inputs.len() > 0 {
@@ -1823,11 +1817,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             }
         }
 
-        if let Some(hir::Node::ImplItem(hir::ImplItem {
+        if let hir::Node::ImplItem(hir::ImplItem {
             kind: hir::ImplItemKind::Fn(_fn_sig, body_id),
             ..
-        })) = self.infcx.tcx.opt_hir_node(self.mir_hir_id())
-            && let Some(hir::Node::Expr(expr)) = self.infcx.tcx.opt_hir_node(body_id.hir_id)
+        }) = self.infcx.tcx.hir_node(self.mir_hir_id())
+            && let hir::Node::Expr(expr) = self.infcx.tcx.hir_node(body_id.hir_id)
         {
             let mut finder = ExpressionFinder {
                 capture_span: *capture_kind_span,
@@ -2395,8 +2389,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 let proper_span = proper_span.source_callsite();
                 if let Some(scope) = self.body.source_scopes.get(source_info.scope)
                     && let ClearCrossCrate::Set(scope_data) = &scope.local_data
-                    && let Some(node) = self.infcx.tcx.opt_hir_node(scope_data.lint_root)
-                    && let Some(id) = node.body_id()
+                    && let Some(id) = self.infcx.tcx.hir_node(scope_data.lint_root).body_id()
                     && let hir::ExprKind::Block(block, _) = self.infcx.tcx.hir().body(id).value.kind
                 {
                     for stmt in block.stmts {

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -87,7 +87,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
                     if let hir::ExprKind::Path(hir::QPath::Resolved(None, p)) = expr.kind
                         && let [hir::PathSegment { ident, args: None, .. }] = p.segments
                         && let hir::def::Res::Local(hir_id) = p.res
-                        && let Some(hir::Node::Pat(pat)) = tcx.opt_hir_node(hir_id)
+                        && let hir::Node::Pat(pat) = tcx.hir_node(hir_id)
                     {
                         err.span_label(pat.span, format!("binding `{ident}` declared here"));
                     }

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -396,7 +396,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
                 let upvar_hir_id = captured_place.get_root_variable();
 
-                if let Some(Node::Pat(pat)) = self.infcx.tcx.opt_hir_node(upvar_hir_id)
+                if let Node::Pat(pat) = self.infcx.tcx.hir_node(upvar_hir_id)
                     && let hir::PatKind::Binding(hir::BindingAnnotation::NONE, _, upvar_ident, _) =
                         pat.kind
                 {
@@ -688,15 +688,15 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         break;
                     }
                     f_in_trait_opt.and_then(|f_in_trait| {
-                        match self.infcx.tcx.opt_hir_node(f_in_trait) {
-                            Some(Node::TraitItem(hir::TraitItem {
+                        match self.infcx.tcx.hir_node(f_in_trait) {
+                            Node::TraitItem(hir::TraitItem {
                                 kind:
                                     hir::TraitItemKind::Fn(
                                         hir::FnSig { decl: hir::FnDecl { inputs, .. }, .. },
                                         _,
                                     ),
                                 ..
-                            })) => {
+                            }) => {
                                 let hir::Ty { span, .. } = inputs[local.index() - 1];
                                 Some(span)
                             }
@@ -759,10 +759,10 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         //
         // `let &b = a;` -> `let &(mut b) = a;`
         if let Some(hir_id) = hir_id
-            && let Some(hir::Node::Local(hir::Local {
+            && let hir::Node::Local(hir::Local {
                 pat: hir::Pat { kind: hir::PatKind::Ref(_, _), .. },
                 ..
-            })) = self.infcx.tcx.opt_hir_node(hir_id)
+            }) = self.infcx.tcx.hir_node(hir_id)
             && let Ok(name) =
                 self.infcx.tcx.sess.source_map().span_to_snippet(local_decl.source_info.span)
         {
@@ -1206,7 +1206,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 };
 
                 if let Some(hir_id) = hir_id
-                    && let Some(hir::Node::Local(local)) = self.infcx.tcx.opt_hir_node(hir_id)
+                    && let hir::Node::Local(local) = self.infcx.tcx.hir_node(hir_id)
                 {
                     let tables = self.infcx.tcx.typeck(def_id.as_local().unwrap());
                     if let Some(clone_trait) = self.infcx.tcx.lang_items().clone_trait()

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -216,7 +216,8 @@ 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(gat_hir_id).generics()
+                    && let Some(generics_impl) =
+                        hir.get_parent(hir.parent_id(gat_hir_id)).generics()
                 {
                     Some((gat_hir_id, generics_impl))
                 } else {

compiler/rustc_hir/src/hir.rs

@@ -835,17 +835,16 @@ pub struct OwnerNodes<'tcx> {
     // The zeroth node's parent should never be accessed: the owner's parent is computed by the
     // hir_owner_parent query. It is set to `ItemLocalId::INVALID` to force an ICE if accidentally
     // used.
-    pub nodes: IndexVec<ItemLocalId, Option<ParentedNode<'tcx>>>,
+    pub nodes: IndexVec<ItemLocalId, ParentedNode<'tcx>>,
     /// Content of local bodies.
     pub bodies: SortedMap<ItemLocalId, &'tcx Body<'tcx>>,
 }
 
 impl<'tcx> OwnerNodes<'tcx> {
     pub fn node(&self) -> OwnerNode<'tcx> {
         use rustc_index::Idx;
-        let node = self.nodes[ItemLocalId::new(0)].as_ref().unwrap().node;
-        let node = node.as_owner().unwrap(); // Indexing must ensure it is an OwnerNode.
-        node
+        // Indexing must ensure it is an OwnerNode.
+        self.nodes[ItemLocalId::new(0)].node.as_owner().unwrap()
     }
 }
 
@@ -860,9 +859,7 @@ impl fmt::Debug for OwnerNodes<'_> {
                     .nodes
                     .iter_enumerated()
                     .map(|(id, parented_node)| {
-                        let parented_node = parented_node.as_ref().map(|node| node.parent);
-
-                        debug_fn(move |f| write!(f, "({id:?}, {parented_node:?})"))
+                        debug_fn(move |f| write!(f, "({id:?}, {:?})", parented_node.parent))
                     })
                     .collect::<Vec<_>>(),
             )
@@ -3356,13 +3353,14 @@ impl<'hir> OwnerNode<'hir> {
         }
     }
 
-    pub fn span(&self) -> Span {
+    #[allow(rustc::pass_by_value)]
+    pub fn span(&self) -> &'hir Span {
         match self {
             OwnerNode::Item(Item { span, .. })
             | OwnerNode::ForeignItem(ForeignItem { span, .. })
             | OwnerNode::ImplItem(ImplItem { span, .. })
-            | OwnerNode::TraitItem(TraitItem { span, .. }) => *span,
-            OwnerNode::Crate(Mod { spans: ModSpans { inner_span, .. }, .. }) => *inner_span,
+            | OwnerNode::TraitItem(TraitItem { span, .. }) => span,
+            OwnerNode::Crate(Mod { spans: ModSpans { inner_span, .. }, .. }) => inner_span,
         }
     }
 
@@ -3491,17 +3489,20 @@ pub enum Node<'hir> {
     Arm(&'hir Arm<'hir>),
     Block(&'hir Block<'hir>),
     Local(&'hir Local<'hir>),
-
     /// `Ctor` refers to the constructor of an enum variant or struct. Only tuple or unit variants
     /// with synthesized constructors.
     Ctor(&'hir VariantData<'hir>),
-
     Lifetime(&'hir Lifetime),
     GenericParam(&'hir GenericParam<'hir>),
-
     Crate(&'hir Mod<'hir>),
-
     Infer(&'hir InferArg),
+    WhereBoundPredicate(&'hir WhereBoundPredicate<'hir>),
+    Let(&'hir Let<'hir>),
+    // Span by reference to minimize `Node`'s size
+    #[allow(rustc::pass_by_value)]
+    ArrayLenInfer(&'hir Span),
+    #[allow(rustc::pass_by_value)]
+    Err(&'hir Span),
 }
 
 impl<'hir> Node<'hir> {
@@ -3546,7 +3547,11 @@ impl<'hir> Node<'hir> {
             | Node::Crate(..)
             | Node::Ty(..)
             | Node::TraitRef(..)
-            | Node::Infer(..) => None,
+            | Node::Infer(..)
+            | Node::WhereBoundPredicate(..)
+            | Node::Let(..)
+            | Node::ArrayLenInfer(..)
+            | Node::Err(..) => None,
         }
     }
 

compiler/rustc_hir/src/intravisit.rs

@@ -108,8 +108,8 @@ impl<'a> FnKind<'a> {
 
 /// An abstract representation of the HIR `rustc_middle::hir::map::Map`.
 pub trait Map<'hir> {
-    /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
-    fn find(&self, hir_id: HirId) -> Option<Node<'hir>>;
+    /// Retrieves the `Node` corresponding to `id`.
+    fn hir_node(&self, hir_id: HirId) -> Node<'hir>;
     fn body(&self, id: BodyId) -> &'hir Body<'hir>;
     fn item(&self, id: ItemId) -> &'hir Item<'hir>;
     fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir>;
@@ -119,7 +119,7 @@ pub trait Map<'hir> {
 
 // Used when no map is actually available, forcing manual implementation of nested visitors.
 impl<'hir> Map<'hir> for ! {
-    fn find(&self, _: HirId) -> Option<Node<'hir>> {
+    fn hir_node(&self, _: HirId) -> Node<'hir> {
         *self;
     }
     fn body(&self, _: BodyId) -> &'hir Body<'hir> {