Stop using CRATE_DEF_INDEX.

`CRATE_DEF_ID` and `CrateNum::as_def_id` are almost always what we want.

5 files changed, 21 insertions, 24 deletions

diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index 54e8c03156d..77995b60a55 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -23,7 +23,7 @@ use rustc_errors::{struct_span_err, Applicability};
 use rustc_expand::base::SyntaxExtension;
 use rustc_expand::expand::AstFragment;
 use rustc_hir::def::{self, *};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX};
+use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
 use rustc_metadata::creader::LoadedMacro;
 use rustc_middle::bug;
 use rustc_middle::metadata::ModChild;
@@ -140,8 +140,8 @@ impl<'a> Resolver<'a> {
                     let parent = def_key.parent.map(|index| {
                         self.get_nearest_non_block_module(DefId { index, krate: def_id.krate })
                     });
-                    let name = if def_id.index == CRATE_DEF_INDEX {
-                        self.cstore().crate_name(def_id.krate)
+                    let name = if let Some(cnum) = def_id.as_crate_root() {
+                        self.cstore().crate_name(cnum)
                     } else {
                         def_key.disambiguated_data.data.get_opt_name().expect("module without name")
                     };
@@ -250,7 +250,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         match vis.kind {
             ast::VisibilityKind::Public => Ok(ty::Visibility::Public),
             ast::VisibilityKind::Crate(..) => {
-                Ok(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)))
+                Ok(ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id()))
             }
             ast::VisibilityKind::Inherited => {
                 Ok(match self.parent_scope.module.kind {
@@ -759,7 +759,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     let mut ctor_vis = if vis == ty::Visibility::Public
                         && self.r.session.contains_name(&item.attrs, sym::non_exhaustive)
                     {
-                        ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
+                        ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
                     } else {
                         vis
                     };
@@ -1108,7 +1108,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 root_span: span,
                 span,
                 module_path: Vec::new(),
-                vis: Cell::new(ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))),
+                vis: Cell::new(ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())),
                 used: Cell::new(false),
             })
         };
@@ -1244,7 +1244,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             let vis = if is_macro_export {
                 ty::Visibility::Public
             } else {
-                ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
+                ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
             };
             let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas);
             self.r.set_binding_parent_module(binding, parent_scope.module);
@@ -1490,7 +1490,7 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
         let ctor_vis = if vis == ty::Visibility::Public
             && self.r.session.contains_name(&variant.attrs, sym::non_exhaustive)
         {
-            ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
+            ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
         } else {
             vis
         };
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index f3b8c1e266c..899980a4c08 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -10,7 +10,7 @@ use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed
 use rustc_feature::BUILTIN_ATTRIBUTES;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind, PerNS};
-use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::PrimTy;
 use rustc_middle::bug;
 use rustc_middle::ty::DefIdTree;
@@ -1167,7 +1167,7 @@ impl<'a> Resolver<'a> {
                 }
                 Scope::ExternPrelude => {
                     suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| {
-                        let res = Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX));
+                        let res = Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id());
                         filter_fn(res).then_some(TypoSuggestion::typo_from_res(ident.name, res))
                     }));
                 }
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 763f31622bc..1a98dd38fc9 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -19,7 +19,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::DiagnosticId;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind, PartialRes, PerNS};
-use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
+use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
 use rustc_hir::{PrimTy, TraitCandidate};
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint;
@@ -2210,7 +2210,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 // trait to resolve.  In that case, we leave the `B`
                 // segment to be resolved by type-check.
                 return Ok(Some(PartialRes::with_unresolved_segments(
-                    Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX)),
+                    Res::Def(DefKind::Mod, CRATE_DEF_ID.to_def_id()),
                     path.len(),
                 )));
             }
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 0926f24ae70..17a9ef4b4db 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -19,7 +19,7 @@ use rustc_errors::{
 use rustc_hir as hir;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind};
-use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::PrimTy;
 use rustc_session::parse::feature_err;
 use rustc_span::edition::Edition;
@@ -351,7 +351,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 }
             })
             .collect::<Vec<_>>();
-        let crate_def_id = DefId::local(CRATE_DEF_INDEX);
+        let crate_def_id = CRATE_DEF_ID.to_def_id();
         if candidates.is_empty() && is_expected(Res::Def(DefKind::Enum, crate_def_id)) {
             let mut enum_candidates: Vec<_> = self
                 .r
@@ -1331,10 +1331,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                             names.extend(extern_prelude.iter().flat_map(|(ident, _)| {
                                 self.r.crate_loader.maybe_process_path_extern(ident.name).and_then(
                                     |crate_id| {
-                                        let crate_mod = Res::Def(
-                                            DefKind::Mod,
-                                            DefId { krate: crate_id, index: CRATE_DEF_INDEX },
-                                        );
+                                        let crate_mod =
+                                            Res::Def(DefKind::Mod, crate_id.as_def_id());
 
                                         if filter_fn(crate_mod) {
                                             Some(TypoSuggestion::typo_from_res(
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 0335c40d70d..5389cb19b58 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -37,7 +37,7 @@ use rustc_expand::base::{DeriveResolutions, SyntaxExtension, SyntaxExtensionKind
 use rustc_hir::def::Namespace::*;
 use rustc_hir::def::{self, CtorOf, DefKind, PartialRes};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefPathHash, LocalDefId};
-use rustc_hir::def_id::{CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
 use rustc_hir::TraitCandidate;
 use rustc_index::vec::IndexVec;
@@ -755,7 +755,7 @@ impl<'a> NameBinding<'a> {
             NameBindingKind::Module(&ModuleData {
                 kind: ModuleKind::Def(DefKind::Mod, def_id, _),
                 ..
-            }) => def_id.index == CRATE_DEF_INDEX,
+            }) => def_id.is_crate_root(),
             _ => false,
         }
     }
@@ -1207,18 +1207,17 @@ impl<'a> Resolver<'a> {
         );
 
         let definitions = Definitions::new(session.local_stable_crate_id(), krate.spans.inner_span);
-        let root = definitions.get_root_def();
 
         let mut visibilities = FxHashMap::default();
         visibilities.insert(CRATE_DEF_ID, ty::Visibility::Public);
 
         let mut def_id_to_node_id = IndexVec::default();
-        assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), root);
+        assert_eq!(def_id_to_node_id.push(CRATE_NODE_ID), CRATE_DEF_ID);
         let mut node_id_to_def_id = FxHashMap::default();
-        node_id_to_def_id.insert(CRATE_NODE_ID, root);
+        node_id_to_def_id.insert(CRATE_NODE_ID, CRATE_DEF_ID);
 
         let mut invocation_parents = FxHashMap::default();
-        invocation_parents.insert(LocalExpnId::ROOT, (root, ImplTraitContext::Existential));
+        invocation_parents.insert(LocalExpnId::ROOT, (CRATE_DEF_ID, ImplTraitContext::Existential));
 
         let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> = session
             .opts