Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 1735 insertions, 0 deletions

diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
new file mode 100644
index 000000000..47b04c33e
--- /dev/null
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -0,0 +1,1405 @@
+use crate::hir::{ModuleItems, Owner};
+use crate::ty::{DefIdTree, TyCtxt};
+use rustc_ast as ast;
+use rustc_data_structures::fingerprint::Fingerprint;
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::svh::Svh;
+use rustc_data_structures::sync::{par_for_each_in, Send, Sync};
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
+use rustc_hir::definitions::{DefKey, DefPath, DefPathHash};
+use rustc_hir::intravisit::{self, Visitor};
+use rustc_hir::*;
+use rustc_index::vec::Idx;
+use rustc_middle::hir::nested_filter;
+use rustc_span::def_id::StableCrateId;
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
+use rustc_span::Span;
+use rustc_target::spec::abi::Abi;
+
+fn fn_decl<'hir>(node: Node<'hir>) -> Option<&'hir FnDecl<'hir>> {
+    match node {
+        Node::Item(Item { kind: ItemKind::Fn(sig, _, _), .. })
+        | Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(sig, _), .. })
+        | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(sig, _), .. }) => Some(&sig.decl),
+        Node::Expr(Expr { kind: ExprKind::Closure(Closure { fn_decl, .. }), .. })
+        | Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_decl, ..), .. }) => {
+            Some(fn_decl)
+        }
+        _ => None,
+    }
+}
+
+pub fn fn_sig<'hir>(node: Node<'hir>) -> Option<&'hir FnSig<'hir>> {
+    match &node {
+        Node::Item(Item { kind: ItemKind::Fn(sig, _, _), .. })
+        | Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(sig, _), .. })
+        | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(sig, _), .. }) => Some(sig),
+        _ => None,
+    }
+}
+
+#[inline]
+pub fn associated_body<'hir>(node: Node<'hir>) -> Option<BodyId> {
+    match node {
+        Node::Item(Item {
+            kind: ItemKind::Const(_, body) | ItemKind::Static(.., body) | ItemKind::Fn(.., body),
+            ..
+        })
+        | Node::TraitItem(TraitItem {
+            kind:
+                TraitItemKind::Const(_, Some(body)) | TraitItemKind::Fn(_, TraitFn::Provided(body)),
+            ..
+        })
+        | Node::ImplItem(ImplItem {
+            kind: ImplItemKind::Const(_, body) | ImplItemKind::Fn(_, body),
+            ..
+        })
+        | Node::Expr(Expr { kind: ExprKind::Closure(Closure { body, .. }), .. }) => Some(*body),
+
+        Node::AnonConst(constant) => Some(constant.body),
+
+        _ => None,
+    }
+}
+
+fn is_body_owner<'hir>(node: Node<'hir>, hir_id: HirId) -> bool {
+    match associated_body(node) {
+        Some(b) => b.hir_id == hir_id,
+        None => false,
+    }
+}
+
+#[derive(Copy, Clone)]
+pub struct Map<'hir> {
+    pub(super) tcx: TyCtxt<'hir>,
+}
+
+/// An iterator that walks up the ancestor tree of a given `HirId`.
+/// Constructed using `tcx.hir().parent_iter(hir_id)`.
+pub struct ParentHirIterator<'hir> {
+    current_id: HirId,
+    map: Map<'hir>,
+}
+
+impl<'hir> Iterator for ParentHirIterator<'hir> {
+    type Item = (HirId, Node<'hir>);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.current_id == CRATE_HIR_ID {
+            return None;
+        }
+        loop {
+            // There are nodes that do not have entries, so we need to skip them.
+            let parent_id = self.map.get_parent_node(self.current_id);
+
+            if parent_id == self.current_id {
+                self.current_id = CRATE_HIR_ID;
+                return None;
+            }
+
+            self.current_id = parent_id;
+            if let Some(node) = self.map.find(parent_id) {
+                return Some((parent_id, node));
+            }
+            // If this `HirId` doesn't have an entry, skip it and look for its `parent_id`.
+        }
+    }
+}
+
+/// An iterator that walks up the ancestor tree of a given `HirId`.
+/// Constructed using `tcx.hir().parent_owner_iter(hir_id)`.
+pub struct ParentOwnerIterator<'hir> {
+    current_id: HirId,
+    map: Map<'hir>,
+}
+
+impl<'hir> Iterator for ParentOwnerIterator<'hir> {
+    type Item = (LocalDefId, OwnerNode<'hir>);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.current_id.local_id.index() != 0 {
+            self.current_id.local_id = ItemLocalId::new(0);
+            if let Some(node) = self.map.tcx.hir_owner(self.current_id.owner) {
+                return Some((self.current_id.owner, node.node));
+            }
+        }
+        if self.current_id == CRATE_HIR_ID {
+            return None;
+        }
+        loop {
+            // There are nodes that do not have entries, so we need to skip them.
+            let parent_id = self.map.def_key(self.current_id.owner).parent;
+
+            let parent_id = parent_id.map_or(CRATE_HIR_ID.owner, |local_def_index| {
+                let def_id = LocalDefId { local_def_index };
+                self.map.local_def_id_to_hir_id(def_id).owner
+            });
+            self.current_id = HirId::make_owner(parent_id);
+
+            // If this `HirId` doesn't have an entry, skip it and look for its `parent_id`.
+            if let Some(node) = self.map.tcx.hir_owner(self.current_id.owner) {
+                return Some((self.current_id.owner, node.node));
+            }
+        }
+    }
+}
+
+impl<'hir> Map<'hir> {
+    pub fn krate(self) -> &'hir Crate<'hir> {
+        self.tcx.hir_crate(())
+    }
+
+    pub fn root_module(self) -> &'hir Mod<'hir> {
+        match self.tcx.hir_owner(CRATE_DEF_ID).map(|o| o.node) {
+            Some(OwnerNode::Crate(item)) => item,
+            _ => bug!(),
+        }
+    }
+
+    pub fn items(self) -> impl Iterator<Item = ItemId> + 'hir {
+        self.tcx.hir_crate_items(()).items.iter().copied()
+    }
+
+    pub fn module_items(self, module: LocalDefId) -> impl Iterator<Item = ItemId> + 'hir {
+        self.tcx.hir_module_items(module).items()
+    }
+
+    pub fn par_for_each_item(self, f: impl Fn(ItemId) + Sync + Send) {
+        par_for_each_in(&self.tcx.hir_crate_items(()).items[..], |id| f(*id));
+    }
+
+    pub fn def_key(self, def_id: LocalDefId) -> DefKey {
+        // Accessing the DefKey is ok, since it is part of DefPathHash.
+        self.tcx.definitions_untracked().def_key(def_id)
+    }
+
+    pub fn def_path_from_hir_id(self, id: HirId) -> Option<DefPath> {
+        self.opt_local_def_id(id).map(|def_id| self.def_path(def_id))
+    }
+
+    pub fn def_path(self, def_id: LocalDefId) -> DefPath {
+        // Accessing the DefPath is ok, since it is part of DefPathHash.
+        self.tcx.definitions_untracked().def_path(def_id)
+    }
+
+    #[inline]
+    pub fn def_path_hash(self, def_id: LocalDefId) -> DefPathHash {
+        // Accessing the DefPathHash is ok, it is incr. comp. stable.
+        self.tcx.definitions_untracked().def_path_hash(def_id)
+    }
+
+    #[inline]
+    pub fn local_def_id(self, hir_id: HirId) -> LocalDefId {
+        self.opt_local_def_id(hir_id).unwrap_or_else(|| {
+            bug!(
+                "local_def_id: no entry for `{:?}`, which has a map of `{:?}`",
+                hir_id,
+                self.find(hir_id)
+            )
+        })
+    }
+
+    #[inline]
+    pub fn opt_local_def_id(self, hir_id: HirId) -> Option<LocalDefId> {
+        if hir_id.local_id == ItemLocalId::new(0) {
+            Some(hir_id.owner)
+        } else {
+            self.tcx
+                .hir_owner_nodes(hir_id.owner)
+                .as_owner()?
+                .local_id_to_def_id
+                .get(&hir_id.local_id)
+                .copied()
+        }
+    }
+
+    #[inline]
+    pub fn local_def_id_to_hir_id(self, def_id: LocalDefId) -> HirId {
+        self.tcx.local_def_id_to_hir_id(def_id)
+    }
+
+    /// Do not call this function directly. The query should be called.
+    pub(super) fn opt_def_kind(self, local_def_id: LocalDefId) -> Option<DefKind> {
+        let hir_id = self.local_def_id_to_hir_id(local_def_id);
+        let def_kind = match self.find(hir_id)? {
+            Node::Item(item) => match item.kind {
+                ItemKind::Static(_, mt, _) => DefKind::Static(mt),
+                ItemKind::Const(..) => DefKind::Const,
+                ItemKind::Fn(..) => DefKind::Fn,
+                ItemKind::Macro(_, macro_kind) => DefKind::Macro(macro_kind),
+                ItemKind::Mod(..) => DefKind::Mod,
+                ItemKind::OpaqueTy(..) => DefKind::OpaqueTy,
+                ItemKind::TyAlias(..) => DefKind::TyAlias,
+                ItemKind::Enum(..) => DefKind::Enum,
+                ItemKind::Struct(..) => DefKind::Struct,
+                ItemKind::Union(..) => DefKind::Union,
+                ItemKind::Trait(..) => DefKind::Trait,
+                ItemKind::TraitAlias(..) => DefKind::TraitAlias,
+                ItemKind::ExternCrate(_) => DefKind::ExternCrate,
+                ItemKind::Use(..) => DefKind::Use,
+                ItemKind::ForeignMod { .. } => DefKind::ForeignMod,
+                ItemKind::GlobalAsm(..) => DefKind::GlobalAsm,
+                ItemKind::Impl { .. } => DefKind::Impl,
+            },
+            Node::ForeignItem(item) => match item.kind {
+                ForeignItemKind::Fn(..) => DefKind::Fn,
+                ForeignItemKind::Static(_, mt) => DefKind::Static(mt),
+                ForeignItemKind::Type => DefKind::ForeignTy,
+            },
+            Node::TraitItem(item) => match item.kind {
+                TraitItemKind::Const(..) => DefKind::AssocConst,
+                TraitItemKind::Fn(..) => DefKind::AssocFn,
+                TraitItemKind::Type(..) => DefKind::AssocTy,
+            },
+            Node::ImplItem(item) => match item.kind {
+                ImplItemKind::Const(..) => DefKind::AssocConst,
+                ImplItemKind::Fn(..) => DefKind::AssocFn,
+                ImplItemKind::TyAlias(..) => DefKind::AssocTy,
+            },
+            Node::Variant(_) => DefKind::Variant,
+            Node::Ctor(variant_data) => {
+                // FIXME(eddyb) is this even possible, if we have a `Node::Ctor`?
+                assert_ne!(variant_data.ctor_hir_id(), None);
+
+                let ctor_of = match self.find(self.get_parent_node(hir_id)) {
+                    Some(Node::Item(..)) => def::CtorOf::Struct,
+                    Some(Node::Variant(..)) => def::CtorOf::Variant,
+                    _ => unreachable!(),
+                };
+                DefKind::Ctor(ctor_of, def::CtorKind::from_hir(variant_data))
+            }
+            Node::AnonConst(_) => {
+                let inline = match self.find(self.get_parent_node(hir_id)) {
+                    Some(Node::Expr(&Expr {
+                        kind: ExprKind::ConstBlock(ref anon_const), ..
+                    })) if anon_const.hir_id == hir_id => true,
+                    _ => false,
+                };
+                if inline { DefKind::InlineConst } else { DefKind::AnonConst }
+            }
+            Node::Field(_) => DefKind::Field,
+            Node::Expr(expr) => match expr.kind {
+                ExprKind::Closure(Closure { movability: None, .. }) => DefKind::Closure,
+                ExprKind::Closure(Closure { movability: Some(_), .. }) => DefKind::Generator,
+                _ => bug!("def_kind: unsupported node: {}", self.node_to_string(hir_id)),
+            },
+            Node::GenericParam(param) => match param.kind {
+                GenericParamKind::Lifetime { .. } => DefKind::LifetimeParam,
+                GenericParamKind::Type { .. } => DefKind::TyParam,
+                GenericParamKind::Const { .. } => DefKind::ConstParam,
+            },
+            Node::Crate(_) => DefKind::Mod,
+            Node::Stmt(_)
+            | Node::PathSegment(_)
+            | Node::Ty(_)
+            | Node::TypeBinding(_)
+            | Node::Infer(_)
+            | Node::TraitRef(_)
+            | Node::Pat(_)
+            | Node::Local(_)
+            | Node::Param(_)
+            | Node::Arm(_)
+            | Node::Lifetime(_)
+            | Node::Block(_) => return None,
+        };
+        Some(def_kind)
+    }
+
+    pub fn find_parent_node(self, id: HirId) -> Option<HirId> {
+        if id.local_id == ItemLocalId::from_u32(0) {
+            Some(self.tcx.hir_owner_parent(id.owner))
+        } else {
+            let owner = self.tcx.hir_owner_nodes(id.owner).as_owner()?;
+            let node = owner.nodes[id.local_id].as_ref()?;
+            let hir_id = HirId { owner: id.owner, local_id: node.parent };
+            Some(hir_id)
+        }
+    }
+
+    pub fn get_parent_node(self, hir_id: HirId) -> HirId {
+        self.find_parent_node(hir_id)
+            .unwrap_or_else(|| bug!("No parent for node {:?}", self.node_to_string(hir_id)))
+    }
+
+    /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
+    pub fn find(self, id: HirId) -> Option<Node<'hir>> {
+        if id.local_id == ItemLocalId::from_u32(0) {
+            let owner = self.tcx.hir_owner(id.owner)?;
+            Some(owner.node.into())
+        } else {
+            let owner = self.tcx.hir_owner_nodes(id.owner).as_owner()?;
+            let node = owner.nodes[id.local_id].as_ref()?;
+            Some(node.node)
+        }
+    }
+
+    /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
+    #[inline]
+    pub fn find_by_def_id(self, id: LocalDefId) -> Option<Node<'hir>> {
+        self.find(self.local_def_id_to_hir_id(id))
+    }
+
+    /// Retrieves the `Node` corresponding to `id`, panicking if it cannot be found.
+    pub fn get(self, id: HirId) -> Node<'hir> {
+        self.find(id).unwrap_or_else(|| bug!("couldn't find hir id {} in the HIR map", id))
+    }
+
+    /// Retrieves the `Node` corresponding to `id`, panicking if it cannot be found.
+    #[inline]
+    pub fn get_by_def_id(self, id: LocalDefId) -> Node<'hir> {
+        self.find_by_def_id(id).unwrap_or_else(|| bug!("couldn't find {:?} in the HIR map", id))
+    }
+
+    pub fn get_if_local(self, id: DefId) -> Option<Node<'hir>> {
+        id.as_local().and_then(|id| self.find(self.local_def_id_to_hir_id(id)))
+    }
+
+    pub fn get_generics(self, id: LocalDefId) -> Option<&'hir Generics<'hir>> {
+        let node = self.tcx.hir_owner(id)?;
+        node.node.generics()
+    }
+
+    pub fn item(self, id: ItemId) -> &'hir Item<'hir> {
+        self.tcx.hir_owner(id.def_id).unwrap().node.expect_item()
+    }
+
+    pub fn trait_item(self, id: TraitItemId) -> &'hir TraitItem<'hir> {
+        self.tcx.hir_owner(id.def_id).unwrap().node.expect_trait_item()
+    }
+
+    pub fn impl_item(self, id: ImplItemId) -> &'hir ImplItem<'hir> {
+        self.tcx.hir_owner(id.def_id).unwrap().node.expect_impl_item()
+    }
+
+    pub fn foreign_item(self, id: ForeignItemId) -> &'hir ForeignItem<'hir> {
+        self.tcx.hir_owner(id.def_id).unwrap().node.expect_foreign_item()
+    }
+
+    pub fn body(self, id: BodyId) -> &'hir Body<'hir> {
+        self.tcx.hir_owner_nodes(id.hir_id.owner).unwrap().bodies[&id.hir_id.local_id]
+    }
+
+    pub fn fn_decl_by_hir_id(self, hir_id: HirId) -> Option<&'hir FnDecl<'hir>> {
+        if let Some(node) = self.find(hir_id) {
+            fn_decl(node)
+        } else {
+            bug!("no node for hir_id `{}`", hir_id)
+        }
+    }
+
+    pub fn fn_sig_by_hir_id(self, hir_id: HirId) -> Option<&'hir FnSig<'hir>> {
+        if let Some(node) = self.find(hir_id) {
+            fn_sig(node)
+        } else {
+            bug!("no node for hir_id `{}`", hir_id)
+        }
+    }
+
+    pub fn enclosing_body_owner(self, hir_id: HirId) -> LocalDefId {
+        for (parent, _) in self.parent_iter(hir_id) {
+            if let Some(body) = self.find(parent).map(associated_body).flatten() {
+                return self.body_owner_def_id(body);
+            }
+        }
+
+        bug!("no `enclosing_body_owner` for hir_id `{}`", hir_id);
+    }
+
+    /// Returns the `HirId` that corresponds to the definition of
+    /// which this is the body of, i.e., a `fn`, `const` or `static`
+    /// item (possibly associated), a closure, or a `hir::AnonConst`.
+    pub fn body_owner(self, BodyId { hir_id }: BodyId) -> HirId {
+        let parent = self.get_parent_node(hir_id);
+        assert!(self.find(parent).map_or(false, |n| is_body_owner(n, hir_id)));
+        parent
+    }
+
+    pub fn body_owner_def_id(self, id: BodyId) -> LocalDefId {
+        self.local_def_id(self.body_owner(id))
+    }
+
+    /// Given a `LocalDefId`, returns the `BodyId` associated with it,
+    /// if the node is a body owner, otherwise returns `None`.
+    pub fn maybe_body_owned_by(self, id: LocalDefId) -> Option<BodyId> {
+        self.get_if_local(id.to_def_id()).map(associated_body).flatten()
+    }
+
+    /// Given a body owner's id, returns the `BodyId` associated with it.
+    pub fn body_owned_by(self, id: LocalDefId) -> BodyId {
+        self.maybe_body_owned_by(id).unwrap_or_else(|| {
+            let hir_id = self.local_def_id_to_hir_id(id);
+            span_bug!(
+                self.span(hir_id),
+                "body_owned_by: {} has no associated body",
+                self.node_to_string(hir_id)
+            );
+        })
+    }
+
+    pub fn body_param_names(self, id: BodyId) -> impl Iterator<Item = Ident> + 'hir {
+        self.body(id).params.iter().map(|arg| match arg.pat.kind {
+            PatKind::Binding(_, _, ident, _) => ident,
+            _ => Ident::empty(),
+        })
+    }
+
+    /// Returns the `BodyOwnerKind` of this `LocalDefId`.
+    ///
+    /// Panics if `LocalDefId` does not have an associated body.
+    pub fn body_owner_kind(self, def_id: LocalDefId) -> BodyOwnerKind {
+        match self.tcx.def_kind(def_id) {
+            DefKind::Const | DefKind::AssocConst | DefKind::InlineConst | DefKind::AnonConst => {
+                BodyOwnerKind::Const
+            }
+            DefKind::Ctor(..) | DefKind::Fn | DefKind::AssocFn => BodyOwnerKind::Fn,
+            DefKind::Closure | DefKind::Generator => BodyOwnerKind::Closure,
+            DefKind::Static(mt) => BodyOwnerKind::Static(mt),
+            dk => bug!("{:?} is not a body node: {:?}", def_id, dk),
+        }
+    }
+
+    /// Returns the `ConstContext` of the body associated with this `LocalDefId`.
+    ///
+    /// Panics if `LocalDefId` does not have an associated body.
+    ///
+    /// This should only be used for determining the context of a body, a return
+    /// value of `Some` does not always suggest that the owner of the body is `const`,
+    /// just that it has to be checked as if it were.
+    pub fn body_const_context(self, def_id: LocalDefId) -> Option<ConstContext> {
+        let ccx = match self.body_owner_kind(def_id) {
+            BodyOwnerKind::Const => ConstContext::Const,
+            BodyOwnerKind::Static(mt) => ConstContext::Static(mt),
+
+            BodyOwnerKind::Fn if self.tcx.is_constructor(def_id.to_def_id()) => return None,
+            BodyOwnerKind::Fn if self.tcx.is_const_fn_raw(def_id.to_def_id()) => {
+                ConstContext::ConstFn
+            }
+            BodyOwnerKind::Fn if self.tcx.is_const_default_method(def_id.to_def_id()) => {
+                ConstContext::ConstFn
+            }
+            BodyOwnerKind::Fn | BodyOwnerKind::Closure => return None,
+        };
+
+        Some(ccx)
+    }
+
+    /// Returns an iterator of the `DefId`s for all body-owners in this
+    /// crate. If you would prefer to iterate over the bodies
+    /// themselves, you can do `self.hir().krate().body_ids.iter()`.
+    pub fn body_owners(self) -> impl Iterator<Item = LocalDefId> + 'hir {
+        self.tcx.hir_crate_items(()).body_owners.iter().copied()
+    }
+
+    pub fn par_body_owners<F: Fn(LocalDefId) + Sync + Send>(self, f: F) {
+        par_for_each_in(&self.tcx.hir_crate_items(()).body_owners[..], |&def_id| f(def_id));
+    }
+
+    pub fn ty_param_owner(self, def_id: LocalDefId) -> LocalDefId {
+        let def_kind = self.tcx.def_kind(def_id);
+        match def_kind {
+            DefKind::Trait | DefKind::TraitAlias => def_id,
+            DefKind::TyParam | DefKind::ConstParam => self.tcx.local_parent(def_id),
+            _ => bug!("ty_param_owner: {:?} is a {:?} not a type parameter", def_id, def_kind),
+        }
+    }
+
+    pub fn ty_param_name(self, def_id: LocalDefId) -> Symbol {
+        let def_kind = self.tcx.def_kind(def_id);
+        match def_kind {
+            DefKind::Trait | DefKind::TraitAlias => kw::SelfUpper,
+            DefKind::TyParam | DefKind::ConstParam => self.tcx.item_name(def_id.to_def_id()),
+            _ => bug!("ty_param_name: {:?} is a {:?} not a type parameter", def_id, def_kind),
+        }
+    }
+
+    pub fn trait_impls(self, trait_did: DefId) -> &'hir [LocalDefId] {
+        self.tcx.all_local_trait_impls(()).get(&trait_did).map_or(&[], |xs| &xs[..])
+    }
+
+    /// Gets the attributes on the crate. This is preferable to
+    /// invoking `krate.attrs` because it registers a tighter
+    /// dep-graph access.
+    pub fn krate_attrs(self) -> &'hir [ast::Attribute] {
+        self.attrs(CRATE_HIR_ID)
+    }
+
+    pub fn rustc_coherence_is_core(self) -> bool {
+        self.krate_attrs().iter().any(|attr| attr.has_name(sym::rustc_coherence_is_core))
+    }
+
+    pub fn get_module(self, module: LocalDefId) -> (&'hir Mod<'hir>, Span, HirId) {
+        let hir_id = HirId::make_owner(module);
+        match self.tcx.hir_owner(module).map(|o| o.node) {
+            Some(OwnerNode::Item(&Item { span, kind: ItemKind::Mod(ref m), .. })) => {
+                (m, span, hir_id)
+            }
+            Some(OwnerNode::Crate(item)) => (item, item.spans.inner_span, hir_id),
+            node => panic!("not a module: {:?}", node),
+        }
+    }
+
+    /// Walks the contents of the local crate. See also `visit_all_item_likes_in_crate`.
+    pub fn walk_toplevel_module(self, visitor: &mut impl Visitor<'hir>) {
+        let (top_mod, span, hir_id) = self.get_module(CRATE_DEF_ID);
+        visitor.visit_mod(top_mod, span, hir_id);
+    }
+
+    /// Walks the attributes in a crate.
+    pub fn walk_attributes(self, visitor: &mut impl Visitor<'hir>) {
+        let krate = self.krate();
+        for info in krate.owners.iter() {
+            if let MaybeOwner::Owner(info) = info {
+                for attrs in info.attrs.map.values() {
+                    for a in *attrs {
+                        visitor.visit_attribute(a)
+                    }
+                }
+            }
+        }
+    }
+
+    /// Visits all item-likes in the crate in some deterministic (but unspecified) order. If you
+    /// need to process every item-like, and don't care about visiting nested items in a particular
+    /// order then this method is the best choice.  If you do care about this nesting, you should
+    /// use the `tcx.hir().walk_toplevel_module`.
+    ///
+    /// Note that this function will access HIR for all the item-likes in the crate.  If you only
+    /// need to access some of them, it is usually better to manually loop on the iterators
+    /// provided by `tcx.hir_crate_items(())`.
+    ///
+    /// Please see the notes in `intravisit.rs` for more information.
+    pub fn visit_all_item_likes_in_crate<V>(self, visitor: &mut V)
+    where
+        V: Visitor<'hir>,
+    {
+        let krate = self.tcx.hir_crate_items(());
+
+        for id in krate.items() {
+            visitor.visit_item(self.item(id));
+        }
+
+        for id in krate.trait_items() {
+            visitor.visit_trait_item(self.trait_item(id));
+        }
+
+        for id in krate.impl_items() {
+            visitor.visit_impl_item(self.impl_item(id));
+        }
+
+        for id in krate.foreign_items() {
+            visitor.visit_foreign_item(self.foreign_item(id));
+        }
+    }
+
+    /// This method is the equivalent of `visit_all_item_likes_in_crate` but restricted to
+    /// item-likes in a single module.
+    pub fn visit_item_likes_in_module<V>(self, module: LocalDefId, visitor: &mut V)
+    where
+        V: Visitor<'hir>,
+    {
+        let module = self.tcx.hir_module_items(module);
+
+        for id in module.items() {
+            visitor.visit_item(self.item(id));
+        }
+
+        for id in module.trait_items() {
+            visitor.visit_trait_item(self.trait_item(id));
+        }
+
+        for id in module.impl_items() {
+            visitor.visit_impl_item(self.impl_item(id));
+        }
+
+        for id in module.foreign_items() {
+            visitor.visit_foreign_item(self.foreign_item(id));
+        }
+    }
+
+    pub fn for_each_module(self, mut f: impl FnMut(LocalDefId)) {
+        let crate_items = self.tcx.hir_crate_items(());
+        for module in crate_items.submodules.iter() {
+            f(*module)
+        }
+    }
+
+    #[cfg(not(parallel_compiler))]
+    #[inline]
+    pub fn par_for_each_module(self, f: impl Fn(LocalDefId)) {
+        self.for_each_module(f)
+    }
+
+    #[cfg(parallel_compiler)]
+    pub fn par_for_each_module(self, f: impl Fn(LocalDefId) + Sync) {
+        use rustc_data_structures::sync::{par_iter, ParallelIterator};
+        par_iter_submodules(self.tcx, CRATE_DEF_ID, &f);
+
+        fn par_iter_submodules<F>(tcx: TyCtxt<'_>, module: LocalDefId, f: &F)
+        where
+            F: Fn(LocalDefId) + Sync,
+        {
+            (*f)(module);
+            let items = tcx.hir_module_items(module);
+            par_iter(&items.submodules[..]).for_each(|&sm| par_iter_submodules(tcx, sm, f));
+        }
+    }
+
+    /// Returns an iterator for the nodes in the ancestor tree of the `current_id`
+    /// until the crate root is reached. Prefer this over your own loop using `get_parent_node`.
+    pub fn parent_iter(self, current_id: HirId) -> ParentHirIterator<'hir> {
+        ParentHirIterator { current_id, map: self }
+    }
+
+    /// Returns an iterator for the nodes in the ancestor tree of the `current_id`
+    /// until the crate root is reached. Prefer this over your own loop using `get_parent_node`.
+    pub fn parent_owner_iter(self, current_id: HirId) -> ParentOwnerIterator<'hir> {
+        ParentOwnerIterator { current_id, map: self }
+    }
+
+    /// Checks if the node is left-hand side of an assignment.
+    pub fn is_lhs(self, id: HirId) -> bool {
+        match self.find(self.get_parent_node(id)) {
+            Some(Node::Expr(expr)) => match expr.kind {
+                ExprKind::Assign(lhs, _rhs, _span) => lhs.hir_id == id,
+                _ => false,
+            },
+            _ => false,
+        }
+    }
+
+    /// Whether the expression pointed at by `hir_id` belongs to a `const` evaluation context.
+    /// Used exclusively for diagnostics, to avoid suggestion function calls.
+    pub fn is_inside_const_context(self, hir_id: HirId) -> bool {
+        self.body_const_context(self.enclosing_body_owner(hir_id)).is_some()
+    }
+
+    /// Retrieves the `HirId` for `id`'s enclosing method, unless there's a
+    /// `while` or `loop` before reaching it, as block tail returns are not
+    /// available in them.
+    ///
+    /// ```
+    /// fn foo(x: usize) -> bool {
+    ///     if x == 1 {
+    ///         true  // If `get_return_block` gets passed the `id` corresponding
+    ///     } else {  // to this, it will return `foo`'s `HirId`.
+    ///         false
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// ```compile_fail,E0308
+    /// fn foo(x: usize) -> bool {
+    ///     loop {
+    ///         true  // If `get_return_block` gets passed the `id` corresponding
+    ///     }         // to this, it will return `None`.
+    ///     false
+    /// }
+    /// ```
+    pub fn get_return_block(self, id: HirId) -> Option<HirId> {
+        let mut iter = self.parent_iter(id).peekable();
+        let mut ignore_tail = false;
+        if let Some(node) = self.find(id) {
+            if let Node::Expr(Expr { kind: ExprKind::Ret(_), .. }) = node {
+                // When dealing with `return` statements, we don't care about climbing only tail
+                // expressions.
+                ignore_tail = true;
+            }
+        }
+        while let Some((hir_id, node)) = iter.next() {
+            if let (Some((_, next_node)), false) = (iter.peek(), ignore_tail) {
+                match next_node {
+                    Node::Block(Block { expr: None, .. }) => return None,
+                    // The current node is not the tail expression of its parent.
+                    Node::Block(Block { expr: Some(e), .. }) if hir_id != e.hir_id => return None,
+                    _ => {}
+                }
+            }
+            match node {
+                Node::Item(_)
+                | Node::ForeignItem(_)
+                | Node::TraitItem(_)
+                | Node::Expr(Expr { kind: ExprKind::Closure { .. }, .. })
+                | Node::ImplItem(_) => return Some(hir_id),
+                // Ignore `return`s on the first iteration
+                Node::Expr(Expr { kind: ExprKind::Loop(..) | ExprKind::Ret(..), .. })
+                | Node::Local(_) => {
+                    return None;
+                }
+                _ => {}
+            }
+        }
+        None
+    }
+
+    /// Retrieves the `HirId` for `id`'s parent item, or `id` itself if no
+    /// parent item is in this map. The "parent item" is the closest parent node
+    /// in the HIR which is recorded by the map and is an item, either an item
+    /// in a module, trait, or impl.
+    pub fn get_parent_item(self, hir_id: HirId) -> LocalDefId {
+        if let Some((def_id, _node)) = self.parent_owner_iter(hir_id).next() {
+            def_id
+        } else {
+            CRATE_DEF_ID
+        }
+    }
+
+    /// Returns the `HirId` of `id`'s nearest module parent, or `id` itself if no
+    /// module parent is in this map.
+    pub(super) fn get_module_parent_node(self, hir_id: HirId) -> LocalDefId {
+        for (def_id, node) in self.parent_owner_iter(hir_id) {
+            if let OwnerNode::Item(&Item { kind: ItemKind::Mod(_), .. }) = node {
+                return def_id;
+            }
+        }
+        CRATE_DEF_ID
+    }
+
+    /// When on an if expression, a match arm tail expression or a match arm, give back
+    /// the enclosing `if` or `match` expression.
+    ///
+    /// Used by error reporting when there's a type error in an if or match arm caused by the
+    /// expression needing to be unit.
+    pub fn get_if_cause(self, hir_id: HirId) -> Option<&'hir Expr<'hir>> {
+        for (_, node) in self.parent_iter(hir_id) {
+            match node {
+                Node::Item(_)
+                | Node::ForeignItem(_)
+                | Node::TraitItem(_)
+                | Node::ImplItem(_)
+                | Node::Stmt(Stmt { kind: StmtKind::Local(_), .. }) => break,
+                Node::Expr(expr @ Expr { kind: ExprKind::If(..) | ExprKind::Match(..), .. }) => {
+                    return Some(expr);
+                }
+                _ => {}
+            }
+        }
+        None
+    }
+
+    /// Returns the nearest enclosing scope. A scope is roughly an item or block.
+    pub fn get_enclosing_scope(self, hir_id: HirId) -> Option<HirId> {
+        for (hir_id, node) in self.parent_iter(hir_id) {
+            if let Node::Item(Item {
+                kind:
+                    ItemKind::Fn(..)
+                    | ItemKind::Const(..)
+                    | ItemKind::Static(..)
+                    | ItemKind::Mod(..)
+                    | ItemKind::Enum(..)
+                    | ItemKind::Struct(..)
+                    | ItemKind::Union(..)
+                    | ItemKind::Trait(..)
+                    | ItemKind::Impl { .. },
+                ..
+            })
+            | Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(..), .. })
+            | Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(..), .. })
+            | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(..), .. })
+            | Node::Block(_) = node
+            {
+                return Some(hir_id);
+            }
+        }
+        None
+    }
+
+    /// Returns the defining scope for an opaque type definition.
+    pub fn get_defining_scope(self, id: HirId) -> HirId {
+        let mut scope = id;
+        loop {
+            scope = self.get_enclosing_scope(scope).unwrap_or(CRATE_HIR_ID);
+            if scope == CRATE_HIR_ID || !matches!(self.get(scope), Node::Block(_)) {
+                return scope;
+            }
+        }
+    }
+
+    pub fn get_foreign_abi(self, hir_id: HirId) -> Abi {
+        let parent = self.get_parent_item(hir_id);
+        if let Some(node) = self.tcx.hir_owner(parent) {
+            if let OwnerNode::Item(Item { kind: ItemKind::ForeignMod { abi, .. }, .. }) = node.node
+            {
+                return *abi;
+            }
+        }
+        bug!(
+            "expected foreign mod or inlined parent, found {}",
+            self.node_to_string(HirId::make_owner(parent))
+        )
+    }
+
+    pub fn expect_owner(self, id: LocalDefId) -> OwnerNode<'hir> {
+        self.tcx.hir_owner(id).unwrap_or_else(|| bug!("expected owner for {:?}", id)).node
+    }
+
+    pub fn expect_item(self, id: LocalDefId) -> &'hir Item<'hir> {
+        match self.tcx.hir_owner(id) {
+            Some(Owner { node: OwnerNode::Item(item), .. }) => item,
+            _ => bug!("expected item, found {}", self.node_to_string(HirId::make_owner(id))),
+        }
+    }
+
+    pub fn expect_impl_item(self, id: LocalDefId) -> &'hir ImplItem<'hir> {
+        match self.tcx.hir_owner(id) {
+            Some(Owner { node: OwnerNode::ImplItem(item), .. }) => item,
+            _ => bug!("expected impl item, found {}", self.node_to_string(HirId::make_owner(id))),
+        }
+    }
+
+    pub fn expect_trait_item(self, id: LocalDefId) -> &'hir TraitItem<'hir> {
+        match self.tcx.hir_owner(id) {
+            Some(Owner { node: OwnerNode::TraitItem(item), .. }) => item,
+            _ => bug!("expected trait item, found {}", self.node_to_string(HirId::make_owner(id))),
+        }
+    }
+
+    pub fn expect_variant(self, id: HirId) -> &'hir Variant<'hir> {
+        match self.find(id) {
+            Some(Node::Variant(variant)) => variant,
+            _ => bug!("expected variant, found {}", self.node_to_string(id)),
+        }
+    }
+
+    pub fn expect_foreign_item(self, id: LocalDefId) -> &'hir ForeignItem<'hir> {
+        match self.tcx.hir_owner(id) {
+            Some(Owner { node: OwnerNode::ForeignItem(item), .. }) => item,
+            _ => {
+                bug!("expected foreign item, found {}", self.node_to_string(HirId::make_owner(id)))
+            }
+        }
+    }
+
+    pub fn expect_expr(self, id: HirId) -> &'hir Expr<'hir> {
+        match self.find(id) {
+            Some(Node::Expr(expr)) => expr,
+            _ => bug!("expected expr, found {}", self.node_to_string(id)),
+        }
+    }
+
+    #[inline]
+    fn opt_ident(self, id: HirId) -> Option<Ident> {
+        match self.get(id) {
+            Node::Pat(&Pat { kind: PatKind::Binding(_, _, ident, _), .. }) => Some(ident),
+            // A `Ctor` doesn't have an identifier itself, but its parent
+            // struct/variant does. Compare with `hir::Map::opt_span`.
+            Node::Ctor(..) => match self.find(self.get_parent_node(id))? {
+                Node::Item(item) => Some(item.ident),
+                Node::Variant(variant) => Some(variant.ident),
+                _ => unreachable!(),
+            },
+            node => node.ident(),
+        }
+    }
+
+    #[inline]
+    pub(super) fn opt_ident_span(self, id: HirId) -> Option<Span> {
+        self.opt_ident(id).map(|ident| ident.span)
+    }
+
+    #[inline]
+    pub fn opt_name(self, id: HirId) -> Option<Symbol> {
+        self.opt_ident(id).map(|ident| ident.name)
+    }
+
+    pub fn name(self, id: HirId) -> Symbol {
+        self.opt_name(id).unwrap_or_else(|| bug!("no name for {}", self.node_to_string(id)))
+    }
+
+    /// Given a node ID, gets a list of attributes associated with the AST
+    /// corresponding to the node-ID.
+    pub fn attrs(self, id: HirId) -> &'hir [ast::Attribute] {
+        self.tcx.hir_attrs(id.owner).get(id.local_id)
+    }
+
+    /// Gets the span of the definition of the specified HIR node.
+    /// This is used by `tcx.def_span`.
+    pub fn span(self, hir_id: HirId) -> Span {
+        self.opt_span(hir_id)
+            .unwrap_or_else(|| bug!("hir::map::Map::span: id not in map: {:?}", hir_id))
+    }
+
+    pub fn opt_span(self, hir_id: HirId) -> Option<Span> {
+        fn until_within(outer: Span, end: Span) -> Span {
+            if let Some(end) = end.find_ancestor_inside(outer) {
+                outer.with_hi(end.hi())
+            } else {
+                outer
+            }
+        }
+
+        fn named_span(item_span: Span, ident: Ident, generics: Option<&Generics<'_>>) -> Span {
+            if ident.name != kw::Empty {
+                let mut span = until_within(item_span, ident.span);
+                if let Some(g) = generics
+                    && !g.span.is_dummy()
+                    && let Some(g_span) = g.span.find_ancestor_inside(item_span)
+                {
+                    span = span.to(g_span);
+                }
+                span
+            } else {
+                item_span
+            }
+        }
+
+        let span = match self.find(hir_id)? {
+            // Function-like.
+            Node::Item(Item { kind: ItemKind::Fn(sig, ..), .. })
+            | Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(sig, ..), .. })
+            | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(sig, ..), .. }) => sig.span,
+            // Constants and Statics.
+            Node::Item(Item {
+                kind:
+                    ItemKind::Const(ty, ..)
+                    | ItemKind::Static(ty, ..)
+                    | ItemKind::Impl(Impl { self_ty: ty, .. }),
+                span: outer_span,
+                ..
+            })
+            | Node::TraitItem(TraitItem {
+                kind: TraitItemKind::Const(ty, ..),
+                span: outer_span,
+                ..
+            })
+            | Node::ImplItem(ImplItem {
+                kind: ImplItemKind::Const(ty, ..),
+                span: outer_span,
+                ..
+            })
+            | Node::ForeignItem(ForeignItem {
+                kind: ForeignItemKind::Static(ty, ..),
+                span: outer_span,
+                ..
+            }) => until_within(*outer_span, ty.span),
+            // With generics and bounds.
+            Node::Item(Item {
+                kind: ItemKind::Trait(_, _, generics, bounds, _),
+                span: outer_span,
+                ..
+            })
+            | Node::TraitItem(TraitItem {
+                kind: TraitItemKind::Type(bounds, _),
+                generics,
+                span: outer_span,
+                ..
+            }) => {
+                let end = if let Some(b) = bounds.last() { b.span() } else { generics.span };
+                until_within(*outer_span, end)
+            }
+            // Other cases.
+            Node::Item(item) => match &item.kind {
+                ItemKind::Use(path, _) => path.span,
+                _ => named_span(item.span, item.ident, item.kind.generics()),
+            },
+            Node::Variant(variant) => named_span(variant.span, variant.ident, None),
+            Node::ImplItem(item) => named_span(item.span, item.ident, Some(item.generics)),
+            Node::ForeignItem(item) => match item.kind {
+                ForeignItemKind::Fn(decl, _, _) => until_within(item.span, decl.output.span()),
+                _ => named_span(item.span, item.ident, None),
+            },
+            Node::Ctor(_) => return self.opt_span(self.get_parent_node(hir_id)),
+            Node::Expr(Expr { kind: ExprKind::Closure(Closure { fn_decl_span, .. }), .. }) => {
+                *fn_decl_span
+            }
+            _ => self.span_with_body(hir_id),
+        };
+        Some(span)
+    }
+
+    /// Like `hir.span()`, but includes the body of items
+    /// (instead of just the item header)
+    pub fn span_with_body(self, hir_id: HirId) -> Span {
+        match self.get(hir_id) {
+            Node::Param(param) => param.span,
+            Node::Item(item) => item.span,
+            Node::ForeignItem(foreign_item) => foreign_item.span,
+            Node::TraitItem(trait_item) => trait_item.span,
+            Node::ImplItem(impl_item) => impl_item.span,
+            Node::Variant(variant) => variant.span,
+            Node::Field(field) => field.span,
+            Node::AnonConst(constant) => self.body(constant.body).value.span,
+            Node::Expr(expr) => expr.span,
+            Node::Stmt(stmt) => stmt.span,
+            Node::PathSegment(seg) => {
+                let ident_span = seg.ident.span;
+                ident_span
+                    .with_hi(seg.args.map_or_else(|| ident_span.hi(), |args| args.span_ext.hi()))
+            }
+            Node::Ty(ty) => ty.span,
+            Node::TypeBinding(tb) => tb.span,
+            Node::TraitRef(tr) => tr.path.span,
+            Node::Pat(pat) => pat.span,
+            Node::Arm(arm) => arm.span,
+            Node::Block(block) => block.span,
+            Node::Ctor(..) => self.span_with_body(self.get_parent_node(hir_id)),
+            Node::Lifetime(lifetime) => lifetime.span,
+            Node::GenericParam(param) => param.span,
+            Node::Infer(i) => i.span,
+            Node::Local(local) => local.span,
+            Node::Crate(item) => item.spans.inner_span,
+        }
+    }
+
+    pub fn span_if_local(self, id: DefId) -> Option<Span> {
+        if id.is_local() { Some(self.tcx.def_span(id)) } else { None }
+    }
+
+    pub fn res_span(self, res: Res) -> Option<Span> {
+        match res {
+            Res::Err => None,
+            Res::Local(id) => Some(self.span(id)),
+            res => self.span_if_local(res.opt_def_id()?),
+        }
+    }
+
+    /// Get a representation of this `id` for debugging purposes.
+    /// NOTE: Do NOT use this in diagnostics!
+    pub fn node_to_string(self, id: HirId) -> String {
+        hir_id_to_string(self, id)
+    }
+
+    /// Returns the HirId of `N` in `struct Foo<const N: usize = { ... }>` when
+    /// called with the HirId for the `{ ... }` anon const
+    pub fn opt_const_param_default_param_hir_id(self, anon_const: HirId) -> Option<HirId> {
+        match self.get(self.get_parent_node(anon_const)) {
+            Node::GenericParam(GenericParam {
+                hir_id: param_id,
+                kind: GenericParamKind::Const { .. },
+                ..
+            }) => Some(*param_id),
+            _ => None,
+        }
+    }
+}
+
+impl<'hir> intravisit::Map<'hir> for Map<'hir> {
+    fn find(&self, hir_id: HirId) -> Option<Node<'hir>> {
+        (*self).find(hir_id)
+    }
+
+    fn body(&self, id: BodyId) -> &'hir Body<'hir> {
+        (*self).body(id)
+    }
+
+    fn item(&self, id: ItemId) -> &'hir Item<'hir> {
+        (*self).item(id)
+    }
+
+    fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir> {
+        (*self).trait_item(id)
+    }
+
+    fn impl_item(&self, id: ImplItemId) -> &'hir ImplItem<'hir> {
+        (*self).impl_item(id)
+    }
+
+    fn foreign_item(&self, id: ForeignItemId) -> &'hir ForeignItem<'hir> {
+        (*self).foreign_item(id)
+    }
+}
+
+pub(super) fn crate_hash(tcx: TyCtxt<'_>, crate_num: CrateNum) -> Svh {
+    debug_assert_eq!(crate_num, LOCAL_CRATE);
+    let krate = tcx.hir_crate(());
+    let hir_body_hash = krate.hir_hash;
+
+    let upstream_crates = upstream_crates(tcx);
+
+    let resolutions = tcx.resolutions(());
+
+    // We hash the final, remapped names of all local source files so we
+    // don't have to include the path prefix remapping commandline args.
+    // If we included the full mapping in the SVH, we could only have
+    // reproducible builds by compiling from the same directory. So we just
+    // hash the result of the mapping instead of the mapping itself.
+    let mut source_file_names: Vec<_> = tcx
+        .sess
+        .source_map()
+        .files()
+        .iter()
+        .filter(|source_file| source_file.cnum == LOCAL_CRATE)
+        .map(|source_file| source_file.name_hash)
+        .collect();
+
+    source_file_names.sort_unstable();
+
+    let crate_hash: Fingerprint = tcx.with_stable_hashing_context(|mut hcx| {
+        let mut stable_hasher = StableHasher::new();
+        hir_body_hash.hash_stable(&mut hcx, &mut stable_hasher);
+        upstream_crates.hash_stable(&mut hcx, &mut stable_hasher);
+        source_file_names.hash_stable(&mut hcx, &mut stable_hasher);
+        if tcx.sess.opts.unstable_opts.incremental_relative_spans {
+            let definitions = tcx.definitions_untracked();
+            let mut owner_spans: Vec<_> = krate
+                .owners
+                .iter_enumerated()
+                .filter_map(|(def_id, info)| {
+                    let _ = info.as_owner()?;
+                    let def_path_hash = definitions.def_path_hash(def_id);
+                    let span = resolutions.source_span[def_id];
+                    debug_assert_eq!(span.parent(), None);
+                    Some((def_path_hash, span))
+                })
+                .collect();
+            owner_spans.sort_unstable_by_key(|bn| bn.0);
+            owner_spans.hash_stable(&mut hcx, &mut stable_hasher);
+        }
+        tcx.sess.opts.dep_tracking_hash(true).hash_stable(&mut hcx, &mut stable_hasher);
+        tcx.sess.local_stable_crate_id().hash_stable(&mut hcx, &mut stable_hasher);
+        // Hash visibility information since it does not appear in HIR.
+        resolutions.visibilities.hash_stable(&mut hcx, &mut stable_hasher);
+        resolutions.has_pub_restricted.hash_stable(&mut hcx, &mut stable_hasher);
+        stable_hasher.finish()
+    });
+
+    Svh::new(crate_hash.to_smaller_hash())
+}
+
+fn upstream_crates(tcx: TyCtxt<'_>) -> Vec<(StableCrateId, Svh)> {
+    let mut upstream_crates: Vec<_> = tcx
+        .crates(())
+        .iter()
+        .map(|&cnum| {
+            let stable_crate_id = tcx.stable_crate_id(cnum);
+            let hash = tcx.crate_hash(cnum);
+            (stable_crate_id, hash)
+        })
+        .collect();
+    upstream_crates.sort_unstable_by_key(|&(stable_crate_id, _)| stable_crate_id);
+    upstream_crates
+}
+
+fn hir_id_to_string(map: Map<'_>, id: HirId) -> String {
+    let id_str = format!(" (hir_id={})", id);
+
+    let path_str = || {
+        // This functionality is used for debugging, try to use `TyCtxt` to get
+        // the user-friendly path, otherwise fall back to stringifying `DefPath`.
+        crate::ty::tls::with_opt(|tcx| {
+            if let Some(tcx) = tcx {
+                let def_id = map.local_def_id(id);
+                tcx.def_path_str(def_id.to_def_id())
+            } else if let Some(path) = map.def_path_from_hir_id(id) {
+                path.data.into_iter().map(|elem| elem.to_string()).collect::<Vec<_>>().join("::")
+            } else {
+                String::from("<missing path>")
+            }
+        })
+    };
+
+    let span_str = || map.tcx.sess.source_map().span_to_snippet(map.span(id)).unwrap_or_default();
+    let node_str = |prefix| format!("{} {}{}", prefix, span_str(), id_str);
+
+    match map.find(id) {
+        Some(Node::Item(item)) => {
+            let item_str = match item.kind {
+                ItemKind::ExternCrate(..) => "extern crate",
+                ItemKind::Use(..) => "use",
+                ItemKind::Static(..) => "static",
+                ItemKind::Const(..) => "const",
+                ItemKind::Fn(..) => "fn",
+                ItemKind::Macro(..) => "macro",
+                ItemKind::Mod(..) => "mod",
+                ItemKind::ForeignMod { .. } => "foreign mod",
+                ItemKind::GlobalAsm(..) => "global asm",
+                ItemKind::TyAlias(..) => "ty",
+                ItemKind::OpaqueTy(..) => "opaque type",
+                ItemKind::Enum(..) => "enum",
+                ItemKind::Struct(..) => "struct",
+                ItemKind::Union(..) => "union",
+                ItemKind::Trait(..) => "trait",
+                ItemKind::TraitAlias(..) => "trait alias",
+                ItemKind::Impl { .. } => "impl",
+            };
+            format!("{} {}{}", item_str, path_str(), id_str)
+        }
+        Some(Node::ForeignItem(_)) => format!("foreign item {}{}", path_str(), id_str),
+        Some(Node::ImplItem(ii)) => match ii.kind {
+            ImplItemKind::Const(..) => {
+                format!("assoc const {} in {}{}", ii.ident, path_str(), id_str)
+            }
+            ImplItemKind::Fn(..) => format!("method {} in {}{}", ii.ident, path_str(), id_str),
+            ImplItemKind::TyAlias(_) => {
+                format!("assoc type {} in {}{}", ii.ident, path_str(), id_str)
+            }
+        },
+        Some(Node::TraitItem(ti)) => {
+            let kind = match ti.kind {
+                TraitItemKind::Const(..) => "assoc constant",
+                TraitItemKind::Fn(..) => "trait method",
+                TraitItemKind::Type(..) => "assoc type",
+            };
+
+            format!("{} {} in {}{}", kind, ti.ident, path_str(), id_str)
+        }
+        Some(Node::Variant(ref variant)) => {
+            format!("variant {} in {}{}", variant.ident, path_str(), id_str)
+        }
+        Some(Node::Field(ref field)) => {
+            format!("field {} in {}{}", field.ident, path_str(), id_str)
+        }
+        Some(Node::AnonConst(_)) => node_str("const"),
+        Some(Node::Expr(_)) => node_str("expr"),
+        Some(Node::Stmt(_)) => node_str("stmt"),
+        Some(Node::PathSegment(_)) => node_str("path segment"),
+        Some(Node::Ty(_)) => node_str("type"),
+        Some(Node::TypeBinding(_)) => node_str("type binding"),
+        Some(Node::TraitRef(_)) => node_str("trait ref"),
+        Some(Node::Pat(_)) => node_str("pat"),
+        Some(Node::Param(_)) => node_str("param"),
+        Some(Node::Arm(_)) => node_str("arm"),
+        Some(Node::Block(_)) => node_str("block"),
+        Some(Node::Infer(_)) => node_str("infer"),
+        Some(Node::Local(_)) => node_str("local"),
+        Some(Node::Ctor(..)) => format!("ctor {}{}", path_str(), id_str),
+        Some(Node::Lifetime(_)) => node_str("lifetime"),
+        Some(Node::GenericParam(ref param)) => format!("generic_param {:?}{}", param, id_str),
+        Some(Node::Crate(..)) => String::from("root_crate"),
+        None => format!("unknown node{}", id_str),
+    }
+}
+
+pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalDefId) -> ModuleItems {
+    let mut collector = ItemCollector::new(tcx, false);
+
+    let (hir_mod, span, hir_id) = tcx.hir().get_module(module_id);
+    collector.visit_mod(hir_mod, span, hir_id);
+
+    let ItemCollector {
+        submodules,
+        items,
+        trait_items,
+        impl_items,
+        foreign_items,
+        body_owners,
+        ..
+    } = collector;
+    return ModuleItems {
+        submodules: submodules.into_boxed_slice(),
+        items: items.into_boxed_slice(),
+        trait_items: trait_items.into_boxed_slice(),
+        impl_items: impl_items.into_boxed_slice(),
+        foreign_items: foreign_items.into_boxed_slice(),
+        body_owners: body_owners.into_boxed_slice(),
+    };
+}
+
+pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
+    let mut collector = ItemCollector::new(tcx, true);
+
+    // A "crate collector" and "module collector" start at a
+    // module item (the former starts at the crate root) but only
+    // the former needs to collect it. ItemCollector does not do this for us.
+    collector.submodules.push(CRATE_DEF_ID);
+    tcx.hir().walk_toplevel_module(&mut collector);
+
+    let ItemCollector {
+        submodules,
+        items,
+        trait_items,
+        impl_items,
+        foreign_items,
+        body_owners,
+        ..
+    } = collector;
+
+    return ModuleItems {
+        submodules: submodules.into_boxed_slice(),
+        items: items.into_boxed_slice(),
+        trait_items: trait_items.into_boxed_slice(),
+        impl_items: impl_items.into_boxed_slice(),
+        foreign_items: foreign_items.into_boxed_slice(),
+        body_owners: body_owners.into_boxed_slice(),
+    };
+}
+
+struct ItemCollector<'tcx> {
+    // When true, it collects all items in the create,
+    // otherwise it collects items in some module.
+    crate_collector: bool,
+    tcx: TyCtxt<'tcx>,
+    submodules: Vec<LocalDefId>,
+    items: Vec<ItemId>,
+    trait_items: Vec<TraitItemId>,
+    impl_items: Vec<ImplItemId>,
+    foreign_items: Vec<ForeignItemId>,
+    body_owners: Vec<LocalDefId>,
+}
+
+impl<'tcx> ItemCollector<'tcx> {
+    fn new(tcx: TyCtxt<'tcx>, crate_collector: bool) -> ItemCollector<'tcx> {
+        ItemCollector {
+            crate_collector,
+            tcx,
+            submodules: Vec::default(),
+            items: Vec::default(),
+            trait_items: Vec::default(),
+            impl_items: Vec::default(),
+            foreign_items: Vec::default(),
+            body_owners: Vec::default(),
+        }
+    }
+}
+
+impl<'hir> Visitor<'hir> for ItemCollector<'hir> {
+    type NestedFilter = nested_filter::All;
+
+    fn nested_visit_map(&mut self) -> Self::Map {
+        self.tcx.hir()
+    }
+
+    fn visit_item(&mut self, item: &'hir Item<'hir>) {
+        if associated_body(Node::Item(item)).is_some() {
+            self.body_owners.push(item.def_id);
+        }
+
+        self.items.push(item.item_id());
+
+        // Items that are modules are handled here instead of in visit_mod.
+        if let ItemKind::Mod(module) = &item.kind {
+            self.submodules.push(item.def_id);
+            // A module collector does not recurse inside nested modules.
+            if self.crate_collector {
+                intravisit::walk_mod(self, module, item.hir_id());
+            }
+        } else {
+            intravisit::walk_item(self, item)
+        }
+    }
+
+    fn visit_foreign_item(&mut self, item: &'hir ForeignItem<'hir>) {
+        self.foreign_items.push(item.foreign_item_id());
+        intravisit::walk_foreign_item(self, item)
+    }
+
+    fn visit_anon_const(&mut self, c: &'hir AnonConst) {
+        self.body_owners.push(self.tcx.hir().local_def_id(c.hir_id));
+        intravisit::walk_anon_const(self, c)
+    }
+
+    fn visit_expr(&mut self, ex: &'hir Expr<'hir>) {
+        if matches!(ex.kind, ExprKind::Closure { .. }) {
+            self.body_owners.push(self.tcx.hir().local_def_id(ex.hir_id));
+        }
+        intravisit::walk_expr(self, ex)
+    }
+
+    fn visit_trait_item(&mut self, item: &'hir TraitItem<'hir>) {
+        if associated_body(Node::TraitItem(item)).is_some() {
+            self.body_owners.push(item.def_id);
+        }
+
+        self.trait_items.push(item.trait_item_id());
+        intravisit::walk_trait_item(self, item)
+    }
+
+    fn visit_impl_item(&mut self, item: &'hir ImplItem<'hir>) {
+        if associated_body(Node::ImplItem(item)).is_some() {
+            self.body_owners.push(item.def_id);
+        }
+
+        self.impl_items.push(item.impl_item_id());
+        intravisit::walk_impl_item(self, item)
+    }
+}
diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs
new file mode 100644
index 000000000..211a61471
--- /dev/null
+++ b/compiler/rustc_middle/src/hir/mod.rs
@@ -0,0 +1,182 @@
+//! HIR datatypes. See the [rustc dev guide] for more info.
+//!
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
+
+pub mod map;
+pub mod nested_filter;
+pub mod place;
+
+use crate::ty::query::Providers;
+use crate::ty::{DefIdTree, ImplSubject, TyCtxt};
+use rustc_data_structures::fingerprint::Fingerprint;
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::sync::{par_for_each_in, Send, Sync};
+use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::*;
+use rustc_query_system::ich::StableHashingContext;
+use rustc_span::{ExpnId, DUMMY_SP};
+
+/// Top-level HIR node for current owner. This only contains the node for which
+/// `HirId::local_id == 0`, and excludes bodies.
+///
+/// This struct exists to encapsulate all access to the hir_owner query in this module, and to
+/// implement HashStable without hashing bodies.
+#[derive(Copy, Clone, Debug)]
+pub struct Owner<'tcx> {
+    node: OwnerNode<'tcx>,
+    hash_without_bodies: Fingerprint,
+}
+
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Owner<'tcx> {
+    #[inline]
+    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
+        let Owner { node: _, hash_without_bodies } = self;
+        hash_without_bodies.hash_stable(hcx, hasher)
+    }
+}
+
+/// Gather the LocalDefId for each item-like within a module, including items contained within
+/// bodies.  The Ids are in visitor order.  This is used to partition a pass between modules.
+#[derive(Debug, HashStable, Encodable, Decodable)]
+pub struct ModuleItems {
+    submodules: Box<[LocalDefId]>,
+    items: Box<[ItemId]>,
+    trait_items: Box<[TraitItemId]>,
+    impl_items: Box<[ImplItemId]>,
+    foreign_items: Box<[ForeignItemId]>,
+    body_owners: Box<[LocalDefId]>,
+}
+
+impl ModuleItems {
+    pub fn items(&self) -> impl Iterator<Item = ItemId> + '_ {
+        self.items.iter().copied()
+    }
+
+    pub fn trait_items(&self) -> impl Iterator<Item = TraitItemId> + '_ {
+        self.trait_items.iter().copied()
+    }
+
+    pub fn impl_items(&self) -> impl Iterator<Item = ImplItemId> + '_ {
+        self.impl_items.iter().copied()
+    }
+
+    pub fn foreign_items(&self) -> impl Iterator<Item = ForeignItemId> + '_ {
+        self.foreign_items.iter().copied()
+    }
+
+    pub fn definitions(&self) -> impl Iterator<Item = LocalDefId> + '_ {
+        self.items
+            .iter()
+            .map(|id| id.def_id)
+            .chain(self.trait_items.iter().map(|id| id.def_id))
+            .chain(self.impl_items.iter().map(|id| id.def_id))
+            .chain(self.foreign_items.iter().map(|id| id.def_id))
+    }
+
+    pub fn par_items(&self, f: impl Fn(ItemId) + Send + Sync) {
+        par_for_each_in(&self.items[..], |&id| f(id))
+    }
+
+    pub fn par_trait_items(&self, f: impl Fn(TraitItemId) + Send + Sync) {
+        par_for_each_in(&self.trait_items[..], |&id| f(id))
+    }
+
+    pub fn par_impl_items(&self, f: impl Fn(ImplItemId) + Send + Sync) {
+        par_for_each_in(&self.impl_items[..], |&id| f(id))
+    }
+
+    pub fn par_foreign_items(&self, f: impl Fn(ForeignItemId) + Send + Sync) {
+        par_for_each_in(&self.foreign_items[..], |&id| f(id))
+    }
+}
+
+impl<'tcx> TyCtxt<'tcx> {
+    #[inline(always)]
+    pub fn hir(self) -> map::Map<'tcx> {
+        map::Map { tcx: self }
+    }
+
+    pub fn parent_module(self, id: HirId) -> LocalDefId {
+        self.parent_module_from_def_id(id.owner)
+    }
+
+    pub fn impl_subject(self, def_id: DefId) -> ImplSubject<'tcx> {
+        self.impl_trait_ref(def_id)
+            .map(ImplSubject::Trait)
+            .unwrap_or_else(|| ImplSubject::Inherent(self.type_of(def_id)))
+    }
+}
+
+pub fn provide(providers: &mut Providers) {
+    providers.parent_module_from_def_id = |tcx, id| {
+        let hir = tcx.hir();
+        hir.get_module_parent_node(hir.local_def_id_to_hir_id(id))
+    };
+    providers.hir_crate_items = map::hir_crate_items;
+    providers.crate_hash = map::crate_hash;
+    providers.hir_module_items = map::hir_module_items;
+    providers.hir_owner = |tcx, id| {
+        let owner = tcx.hir_crate(()).owners.get(id)?.as_owner()?;
+        let node = owner.node();
+        Some(Owner { node, hash_without_bodies: owner.nodes.hash_without_bodies })
+    };
+    providers.local_def_id_to_hir_id = |tcx, id| {
+        let owner = tcx.hir_crate(()).owners[id].map(|_| ());
+        match owner {
+            MaybeOwner::Owner(_) => HirId::make_owner(id),
+            MaybeOwner::Phantom => bug!("No HirId for {:?}", id),
+            MaybeOwner::NonOwner(hir_id) => hir_id,
+        }
+    };
+    providers.hir_owner_nodes = |tcx, id| tcx.hir_crate(()).owners[id].map(|i| &i.nodes);
+    providers.hir_owner_parent = |tcx, id| {
+        // Accessing the local_parent is ok since its value is hashed as part of `id`'s DefPathHash.
+        tcx.opt_local_parent(id).map_or(CRATE_HIR_ID, |parent| {
+            let mut parent_hir_id = tcx.hir().local_def_id_to_hir_id(parent);
+            if let Some(local_id) =
+                tcx.hir_crate(()).owners[parent_hir_id.owner].unwrap().parenting.get(&id)
+            {
+                parent_hir_id.local_id = *local_id;
+            }
+            parent_hir_id
+        })
+    };
+    providers.hir_attrs =
+        |tcx, id| tcx.hir_crate(()).owners[id].as_owner().map_or(AttributeMap::EMPTY, |o| &o.attrs);
+    providers.source_span =
+        |tcx, def_id| tcx.resolutions(()).source_span.get(def_id).copied().unwrap_or(DUMMY_SP);
+    providers.def_span = |tcx, def_id| {
+        let def_id = def_id.expect_local();
+        let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
+        tcx.hir().opt_span(hir_id).unwrap_or(DUMMY_SP)
+    };
+    providers.def_ident_span = |tcx, def_id| {
+        let def_id = def_id.expect_local();
+        let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
+        tcx.hir().opt_ident_span(hir_id)
+    };
+    providers.fn_arg_names = |tcx, id| {
+        let hir = tcx.hir();
+        let def_id = id.expect_local();
+        let hir_id = hir.local_def_id_to_hir_id(def_id);
+        if let Some(body_id) = hir.maybe_body_owned_by(def_id) {
+            tcx.arena.alloc_from_iter(hir.body_param_names(body_id))
+        } else if let Node::TraitItem(&TraitItem {
+            kind: TraitItemKind::Fn(_, TraitFn::Required(idents)),
+            ..
+        }) = hir.get(hir_id)
+        {
+            tcx.arena.alloc_slice(idents)
+        } else {
+            span_bug!(hir.span(hir_id), "fn_arg_names: unexpected item {:?}", id);
+        }
+    };
+    providers.opt_def_kind = |tcx, def_id| tcx.hir().opt_def_kind(def_id.expect_local());
+    providers.all_local_trait_impls = |tcx, ()| &tcx.resolutions(()).trait_impls;
+    providers.expn_that_defined = |tcx, id| {
+        let id = id.expect_local();
+        tcx.resolutions(()).expn_that_defined.get(&id).copied().unwrap_or(ExpnId::root())
+    };
+    providers.in_scope_traits_map =
+        |tcx, id| tcx.hir_crate(()).owners[id].as_owner().map(|owner_info| &owner_info.trait_map);
+}
diff --git a/compiler/rustc_middle/src/hir/nested_filter.rs b/compiler/rustc_middle/src/hir/nested_filter.rs
new file mode 100644
index 000000000..6896837aa
--- /dev/null
+++ b/compiler/rustc_middle/src/hir/nested_filter.rs
@@ -0,0 +1,31 @@
+use rustc_hir::intravisit::nested_filter::NestedFilter;
+
+/// Do not visit nested item-like things, but visit nested things
+/// that are inside of an item-like.
+///
+/// Notably, possible occurrences of bodies in non-item-like things
+/// include: closures/generators, inline `const {}` blocks, and
+/// constant arguments of types, e.g. in `let _: [(); /* HERE */];`.
+///
+/// **This is the most common choice.** A very common pattern is
+/// to use `visit_all_item_likes_in_crate()` as an outer loop,
+/// and to have the visitor that visits the contents of each item
+/// using this setting.
+pub struct OnlyBodies(());
+impl<'hir> NestedFilter<'hir> for OnlyBodies {
+    type Map = crate::hir::map::Map<'hir>;
+    const INTER: bool = false;
+    const INTRA: bool = true;
+}
+
+/// Visits all nested things, including item-likes.
+///
+/// **This is an unusual choice.** It is used when you want to
+/// process everything within their lexical context. Typically you
+/// kick off the visit by doing `walk_krate()`.
+pub struct All(());
+impl<'hir> NestedFilter<'hir> for All {
+    type Map = crate::hir::map::Map<'hir>;
+    const INTER: bool = true;
+    const INTRA: bool = true;
+}
diff --git a/compiler/rustc_middle/src/hir/place.rs b/compiler/rustc_middle/src/hir/place.rs
new file mode 100644
index 000000000..83d3b0100
--- /dev/null
+++ b/compiler/rustc_middle/src/hir/place.rs
@@ -0,0 +1,117 @@
+use crate::ty;
+use crate::ty::Ty;
+
+use rustc_hir::HirId;
+use rustc_target::abi::VariantIdx;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
+pub enum PlaceBase {
+    /// A temporary variable.
+    Rvalue,
+    /// A named `static` item.
+    StaticItem,
+    /// A named local variable.
+    Local(HirId),
+    /// An upvar referenced by closure env.
+    Upvar(ty::UpvarId),
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
+pub enum ProjectionKind {
+    /// A dereference of a pointer, reference or `Box<T>` of the given type.
+    Deref,
+
+    /// `B.F` where `B` is the base expression and `F` is
+    /// the field. The field is identified by which variant
+    /// it appears in along with a field index. The variant
+    /// is used for enums.
+    Field(u32, VariantIdx),
+
+    /// Some index like `B[x]`, where `B` is the base
+    /// expression. We don't preserve the index `x` because
+    /// we won't need it.
+    Index,
+
+    /// A subslice covering a range of values like `B[x..y]`.
+    Subslice,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
+pub struct Projection<'tcx> {
+    /// Type after the projection is applied.
+    pub ty: Ty<'tcx>,
+
+    /// Defines the kind of access made by the projection.
+    pub kind: ProjectionKind,
+}
+
+/// A `Place` represents how a value is located in memory.
+///
+/// This is an HIR version of [`rustc_middle::mir::Place`].
+#[derive(Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
+pub struct Place<'tcx> {
+    /// The type of the `PlaceBase`
+    pub base_ty: Ty<'tcx>,
+    /// The "outermost" place that holds this value.
+    pub base: PlaceBase,
+    /// How this place is derived from the base place.
+    pub projections: Vec<Projection<'tcx>>,
+}
+
+/// A `PlaceWithHirId` represents how a value is located in memory.
+///
+/// This is an HIR version of [`rustc_middle::mir::Place`].
+#[derive(Clone, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
+pub struct PlaceWithHirId<'tcx> {
+    /// `HirId` of the expression or pattern producing this value.
+    pub hir_id: HirId,
+
+    /// Information about the `Place`.
+    pub place: Place<'tcx>,
+}
+
+impl<'tcx> PlaceWithHirId<'tcx> {
+    pub fn new(
+        hir_id: HirId,
+        base_ty: Ty<'tcx>,
+        base: PlaceBase,
+        projections: Vec<Projection<'tcx>>,
+    ) -> PlaceWithHirId<'tcx> {
+        PlaceWithHirId { hir_id, place: Place { base_ty, base, projections } }
+    }
+}
+
+impl<'tcx> Place<'tcx> {
+    /// Returns an iterator of the types that have to be dereferenced to access
+    /// the `Place`.
+    ///
+    /// The types are in the reverse order that they are applied. So if
+    /// `x: &*const u32` and the `Place` is `**x`, then the types returned are
+    ///`*const u32` then `&*const u32`.
+    pub fn deref_tys(&self) -> impl Iterator<Item = Ty<'tcx>> + '_ {
+        self.projections.iter().enumerate().rev().filter_map(move |(index, proj)| {
+            if ProjectionKind::Deref == proj.kind {
+                Some(self.ty_before_projection(index))
+            } else {
+                None
+            }
+        })
+    }
+
+    /// Returns the type of this `Place` after all projections have been applied.
+    pub fn ty(&self) -> Ty<'tcx> {
+        self.projections.last().map_or(self.base_ty, |proj| proj.ty)
+    }
+
+    /// Returns the type of this `Place` immediately before `projection_index`th projection
+    /// is applied.
+    pub fn ty_before_projection(&self, projection_index: usize) -> Ty<'tcx> {
+        assert!(projection_index < self.projections.len());
+        if projection_index == 0 { self.base_ty } else { self.projections[projection_index - 1].ty }
+    }
+}