Rollup merge of rust-lang#71116 - marmeladema:dummy-hir-id-removal, r=eddyb

Entirely remove `DUMMY_HIR_ID` Some helpers functions have been introduced to deal with (buggy) cases where either a `NodeId` or a `DefId` do not have a corresponding `HirId`. Those cases are tracked in issue rust-lang#71104.

Author: Centril

src/librustc_ast_lowering/lib.rs

@@ -168,7 +168,7 @@ struct LoweringContext<'a, 'hir: 'a> {
 
  current_hir_id_owner: Vec<(LocalDefId, u32)>,
  item_local_id_counters: NodeMap<u32>,
- node_id_to_hir_id: IndexVec<NodeId, hir::HirId>,
+ node_id_to_hir_id: IndexVec<NodeId, Option<hir::HirId>>,
 
  allow_try_trait: Option<Lrc<[Symbol]>>,
  allow_gen_future: Option<Lrc<[Symbol]>>,
@@ -522,15 +522,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
  }
 
  self.lower_node_id(CRATE_NODE_ID);
- debug_assert!(self.node_id_to_hir_id[CRATE_NODE_ID] == hir::CRATE_HIR_ID);
+ debug_assert!(self.node_id_to_hir_id[CRATE_NODE_ID] == Some(hir::CRATE_HIR_ID));
 
  visit::walk_crate(&mut MiscCollector { lctx: &mut self, hir_id_owner: None }, c);
  visit::walk_crate(&mut item::ItemLowerer { lctx: &mut self }, c);
 
  let module = self.lower_mod(&c.module);
  let attrs = self.lower_attrs(&c.attrs);
  let body_ids = body_ids(&self.bodies);
- let proc_macros = c.proc_macros.iter().map(|id| self.node_id_to_hir_id[*id]).collect();
+ let proc_macros =
+ c.proc_macros.iter().map(|id| self.node_id_to_hir_id[*id].unwrap()).collect();
 
  self.resolver.definitions().init_node_id_to_hir_id_mapping(self.node_id_to_hir_id);
 
@@ -571,26 +572,22 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
  ast_node_id: NodeId,
  alloc_hir_id: impl FnOnce(&mut Self) -> hir::HirId,
  ) -> hir::HirId {
- if ast_node_id == DUMMY_NODE_ID {
- return hir::DUMMY_HIR_ID;
- }
+ assert_ne!(ast_node_id, DUMMY_NODE_ID);
 
  let min_size = ast_node_id.as_usize() + 1;
 
  if min_size > self.node_id_to_hir_id.len() {
- self.node_id_to_hir_id.resize(min_size, hir::DUMMY_HIR_ID);
+ self.node_id_to_hir_id.resize(min_size, None);
  }
 
- let existing_hir_id = self.node_id_to_hir_id[ast_node_id];
-
- if existing_hir_id == hir::DUMMY_HIR_ID {
+ if let Some(existing_hir_id) = self.node_id_to_hir_id[ast_node_id] {
+ existing_hir_id
+ } else {
  // Generate a new `HirId`.
  let hir_id = alloc_hir_id(self);
- self.node_id_to_hir_id[ast_node_id] = hir_id;
+ self.node_id_to_hir_id[ast_node_id] = Some(hir_id);
 
  hir_id
- } else {
- existing_hir_id
  }
  }
 

src/librustc_hir/definitions.rs

@@ -7,7 +7,6 @@
 pub use crate::def_id::DefPathHash;
 use crate::def_id::{CrateNum, DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use crate::hir;
-use crate::hir_id::DUMMY_HIR_ID;
 
 use rustc_ast::ast;
 use rustc_ast::crate_disambiguator::CrateDisambiguator;
@@ -87,7 +86,7 @@ pub struct Definitions {
  node_id_to_def_id: FxHashMap<ast::NodeId, LocalDefId>,
  def_id_to_node_id: IndexVec<LocalDefId, ast::NodeId>,
 
- pub(super) node_id_to_hir_id: IndexVec<ast::NodeId, hir::HirId>,
+ pub(super) node_id_to_hir_id: IndexVec<ast::NodeId, Option<hir::HirId>>,
  /// The reverse mapping of `node_id_to_hir_id`.
  pub(super) hir_id_to_node_id: FxHashMap<hir::HirId, ast::NodeId>,
 
@@ -345,8 +344,7 @@ impl Definitions {
  #[inline]
  pub fn as_local_hir_id(&self, def_id: DefId) -> Option<hir::HirId> {
  if let Some(def_id) = def_id.as_local() {
- let hir_id = self.local_def_id_to_hir_id(def_id);
- if hir_id != DUMMY_HIR_ID { Some(hir_id) } else { None }
+ Some(self.local_def_id_to_hir_id(def_id))
  } else {
  None
  }
@@ -359,11 +357,22 @@ impl Definitions {
 
  #[inline]
  pub fn node_id_to_hir_id(&self, node_id: ast::NodeId) -> hir::HirId {
+ self.node_id_to_hir_id[node_id].unwrap()
+ }
+
+ #[inline]
+ pub fn opt_node_id_to_hir_id(&self, node_id: ast::NodeId) -> Option<hir::HirId> {
  self.node_id_to_hir_id[node_id]
  }
 
  #[inline]
  pub fn local_def_id_to_hir_id(&self, id: LocalDefId) -> hir::HirId {
+ let node_id = self.def_id_to_node_id[id];
+ self.node_id_to_hir_id[node_id].unwrap()
+ }
+
+ #[inline]
+ pub fn opt_local_def_id_to_hir_id(&self, id: LocalDefId) -> Option<hir::HirId> {
  let node_id = self.def_id_to_node_id[id];
  self.node_id_to_hir_id[node_id]
  }
@@ -470,7 +479,10 @@ impl Definitions {
 
  /// Initializes the `ast::NodeId` to `HirId` mapping once it has been generated during
  /// AST to HIR lowering.
- pub fn init_node_id_to_hir_id_mapping(&mut self, mapping: IndexVec<ast::NodeId, hir::HirId>) {
+ pub fn init_node_id_to_hir_id_mapping(
+ &mut self,
+ mapping: IndexVec<ast::NodeId, Option<hir::HirId>>,
+ ) {
  assert!(
  self.node_id_to_hir_id.is_empty(),
  "trying to initialize `NodeId` -> `HirId` mapping twice"
@@ -481,7 +493,7 @@ impl Definitions {
  self.hir_id_to_node_id = self
  .node_id_to_hir_id
  .iter_enumerated()
- .map(|(node_id, &hir_id)| (hir_id, node_id))
+ .filter_map(|(node_id, &hir_id)| hir_id.map(|hir_id| (hir_id, node_id)))
  .collect();
  }
 

src/librustc_hir/hir_id.rs

@@ -45,7 +45,4 @@ pub const CRATE_HIR_ID: HirId = HirId {
  local_id: ItemLocalId::from_u32(0),
 };
 
-pub const DUMMY_HIR_ID: HirId =
- HirId { owner: LocalDefId { local_def_index: CRATE_DEF_INDEX }, local_id: DUMMY_ITEM_LOCAL_ID };
-
 pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId::MAX;

src/librustc_middle/hir/map/collector.rs

@@ -250,23 +250,16 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
  None => format!("{:?}", node),
  };
 
- let forgot_str = if hir_id == hir::DUMMY_HIR_ID {
- format!("\nMaybe you forgot to lower the node id {:?}?", node_id)
- } else {
- String::new()
- };
-
  span_bug!(
  span,
  "inconsistent DepNode at `{:?}` for `{}`: \
- current_dep_node_owner={} ({:?}), hir_id.owner={} ({:?}){}",
+ current_dep_node_owner={} ({:?}), hir_id.owner={} ({:?})",
  self.source_map.span_to_string(span),
  node_str,
  self.definitions.def_path(self.current_dep_node_owner).to_string_no_crate(),
  self.current_dep_node_owner,
  self.definitions.def_path(hir_id.owner).to_string_no_crate(),
  hir_id.owner,
- forgot_str,
  )
  }
  }

src/librustc_middle/hir/map/mod.rs

@@ -214,11 +214,21 @@ impl<'hir> Map<'hir> {
  self.tcx.definitions.node_id_to_hir_id(node_id)
  }
 
+ #[inline]
+ pub fn opt_node_id_to_hir_id(&self, node_id: NodeId) -> Option<HirId> {
+ self.tcx.definitions.opt_node_id_to_hir_id(node_id)
+ }
+
  #[inline]
  pub fn local_def_id_to_hir_id(&self, def_id: LocalDefId) -> HirId {
  self.tcx.definitions.local_def_id_to_hir_id(def_id)
  }
 
+ #[inline]
+ pub fn opt_local_def_id_to_hir_id(&self, def_id: LocalDefId) -> Option<HirId> {
+ self.tcx.definitions.opt_local_def_id_to_hir_id(def_id)
+ }
+
  pub fn def_kind(&self, hir_id: HirId) -> Option<DefKind> {
  let node = self.find(hir_id)?;
 

src/librustc_middle/middle/stability.rs

@@ -215,7 +215,6 @@ fn late_report_deprecation(
  suggestion: Option<Symbol>,
  lint: &'static Lint,
  span: Span,
- def_id: DefId,
  hir_id: HirId,
 ) {
  if span.in_derive_expansion() {
@@ -229,9 +228,6 @@ fn late_report_deprecation(
  }
  diag.emit()
  });
- if hir_id == hir::DUMMY_HIR_ID {
- span_bug!(span, "emitted a {} lint with dummy HIR id: {:?}", lint.name, def_id);
- }
 }
 
 /// Result of `TyCtxt::eval_stability`.
@@ -296,7 +292,7 @@ impl<'tcx> TyCtxt<'tcx> {
  if !skip {
  let (message, lint) =
  deprecation_message(&depr_entry.attr, &self.def_path_str(def_id));
- late_report_deprecation(self, &message, None, lint, span, def_id, id);
+ late_report_deprecation(self, &message, None, lint, span, id);
  }
  };
  }
@@ -319,15 +315,7 @@ impl<'tcx> TyCtxt<'tcx> {
  if let Some(depr) = &stability.rustc_depr {
  let (message, lint) =
  rustc_deprecation_message(depr, &self.def_path_str(def_id));
- late_report_deprecation(
- self,
- &message,
- depr.suggestion,
- lint,
- span,
- def_id,
- id,
- );
+ late_report_deprecation(self, &message, depr.suggestion, lint, span, id);
  }
  }
  }

src/librustc_middle/ty/context.rs

@@ -1126,13 +1126,16 @@ impl<'tcx> TyCtxt<'tcx> {
 
  let mut trait_map: FxHashMap<_, FxHashMap<_, _>> = FxHashMap::default();
  for (k, v) in resolutions.trait_map {
- let hir_id = definitions.node_id_to_hir_id(k);
- let map = trait_map.entry(hir_id.owner).or_default();
- let v = v
- .into_iter()
- .map(|tc| tc.map_import_ids(|id| definitions.node_id_to_hir_id(id)))
- .collect();
- map.insert(hir_id.local_id, StableVec::new(v));
+ // FIXME(#71104) Should really be using just `node_id_to_hir_id` but
+ // some `NodeId` do not seem to have a corresponding HirId.
+ if let Some(hir_id) = definitions.opt_node_id_to_hir_id(k) {
+ let map = trait_map.entry(hir_id.owner).or_default();
+ let v = v
+ .into_iter()
+ .map(|tc| tc.map_import_ids(|id| definitions.node_id_to_hir_id(id)))
+ .collect();
+ map.insert(hir_id.local_id, StableVec::new(v));
+ }
  }
 
  GlobalCtxt {

src/librustc_passes/hir_id_validator.rs

@@ -143,16 +143,6 @@ impl<'a, 'hir> intravisit::Visitor<'hir> for HirIdValidator<'a, 'hir> {
  fn visit_id(&mut self, hir_id: HirId) {
  let owner = self.owner.expect("no owner");
 
- if hir_id == hir::DUMMY_HIR_ID {
- self.error(|| {
- format!(
- "HirIdValidator: HirId {:?} is invalid",
- self.hir_map.node_to_string(hir_id)
- )
- });
- return;
- }
-
  if owner != hir_id.owner {
  self.error(|| {
  format!(

src/librustc_privacy/lib.rs

@@ -928,7 +928,12 @@ impl Visitor<'tcx> for EmbargoVisitor<'tcx> {
 
  let macro_module_def_id =
  ty::DefIdTree::parent(self.tcx, self.tcx.hir().local_def_id(md.hir_id)).unwrap();
- let mut module_id = match self.tcx.hir().as_local_hir_id(macro_module_def_id) {
+ // FIXME(#71104) Should really be using just `as_local_hir_id` but
+ // some `DefId` do not seem to have a corresponding HirId.
+ let hir_id = macro_module_def_id
+ .as_local()
+ .and_then(|def_id| self.tcx.hir().opt_local_def_id_to_hir_id(def_id));
+ let mut module_id = match hir_id {
  Some(module_id) if self.tcx.hir().is_hir_id_module(module_id) => module_id,
  // `module_id` doesn't correspond to a `mod`, return early (#63164, #65252).
  _ => return,

src/librustc_resolve/late/lifetimes.rs

@@ -2704,14 +2704,6 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
  }
 
  fn insert_lifetime(&mut self, lifetime_ref: &'tcx hir::Lifetime, def: Region) {
- if lifetime_ref.hir_id == hir::DUMMY_HIR_ID {
- span_bug!(
- lifetime_ref.span,
- "lifetime reference not renumbered, \
- probably a bug in rustc_ast::fold"
- );
- }
-
  debug!(
  "insert_lifetime: {} resolved to {:?} span={:?}",
  self.tcx.hir().node_to_string(lifetime_ref.hir_id),