Rollup merge of #96142 - cjgillot:no-crate-def-index, r=petrochenkov

Stop using CRATE_DEF_INDEX outside of metadata encoding.

`CRATE_DEF_ID` and `CrateNum::as_def_id` are almost always what we want.  We should not manipulate raw `DefIndex` outside of metadata encoding.

7 files changed, 17 insertions, 27 deletions

diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 21016afbf5f..a070cef2272 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -15,7 +15,7 @@ use rustc_attr as attr;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
-use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
 use rustc_middle::middle::resolve_lifetime as rl;
 use rustc_middle::ty::fold::TypeFolder;
@@ -1975,7 +1975,7 @@ fn clean_extern_crate(
     // this is the ID of the `extern crate` statement
     let cnum = cx.tcx.extern_mod_stmt_cnum(krate.def_id).unwrap_or(LOCAL_CRATE);
     // this is the ID of the crate itself
-    let crate_def_id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
+    let crate_def_id = cnum.as_def_id();
     let attrs = cx.tcx.hir().attrs(krate.hir_id());
     let ty_vis = cx.tcx.visibility(krate.def_id);
     let please_inline = ty_vis.is_public()
@@ -2094,7 +2094,7 @@ fn clean_use_statement(
     } else {
         if inline_attr.is_none() {
             if let Res::Def(DefKind::Mod, did) = path.res {
-                if !did.is_local() && did.index == CRATE_DEF_INDEX {
+                if !did.is_local() && did.is_crate_root() {
                     // if we're `pub use`ing an extern crate root, don't inline it unless we
                     // were specifically asked for it
                     denied = true;
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 4b473df155f..e30bc6e0a97 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -20,7 +20,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{BodyId, Mutability};
 use rustc_index::vec::IndexVec;
@@ -104,14 +104,6 @@ impl ItemId {
             ItemId::Primitive(_, krate) => krate,
         }
     }
-
-    #[inline]
-    crate fn index(self) -> Option<DefIndex> {
-        match self {
-            ItemId::DefId(id) => Some(id.index),
-            _ => None,
-        }
-    }
 }
 
 impl From<DefId> for ItemId {
@@ -160,7 +152,7 @@ impl ExternalCrate {
 
     #[inline]
     crate fn def_id(&self) -> DefId {
-        DefId { krate: self.crate_num, index: CRATE_DEF_INDEX }
+        self.crate_num.as_def_id()
     }
 
     crate fn src(&self, tcx: TyCtxt<'_>) -> FileName {
@@ -217,7 +209,7 @@ impl ExternalCrate {
 
         // Failing that, see if there's an attribute specifying where to find this
         // external crate
-        let did = DefId { krate: self.crate_num, index: CRATE_DEF_INDEX };
+        let did = self.crate_num.as_def_id();
         tcx.get_attrs(did)
             .lists(sym::doc)
             .filter(|a| a.has_name(sym::html_root_url))
@@ -559,7 +551,7 @@ impl Item {
     }
 
     crate fn is_crate(&self) -> bool {
-        self.is_mod() && self.item_id.as_def_id().map_or(false, |did| did.index == CRATE_DEF_INDEX)
+        self.is_mod() && self.item_id.as_def_id().map_or(false, |did| did.is_crate_root())
     }
     crate fn is_mod(&self) -> bool {
         self.type_() == ItemType::Module
diff --git a/src/librustdoc/formats/cache.rs b/src/librustdoc/formats/cache.rs
index 06e7c9e763d..b4d2772b31d 100644
--- a/src/librustdoc/formats/cache.rs
+++ b/src/librustdoc/formats/cache.rs
@@ -1,7 +1,7 @@
 use std::mem;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
+use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_middle::middle::privacy::AccessLevels;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::{sym, Symbol};
@@ -302,7 +302,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                     // A crate has a module at its root, containing all items,
                     // which should not be indexed. The crate-item itself is
                     // inserted later on when serializing the search-index.
-                    if item.item_id.index().map_or(false, |idx| idx != CRATE_DEF_INDEX) {
+                    if item.item_id.as_def_id().map_or(false, |idx| !idx.is_crate_root()) {
                         let desc = item.doc_value().map_or_else(String::new, |x| {
                             short_markdown_summary(x.as_str(), &item.link_names(self.cache))
                         });
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 55b0028180f..6954e2363f5 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -18,7 +18,6 @@ use rustc_hir::def_id::DefId;
 use rustc_middle::ty;
 use rustc_middle::ty::DefIdTree;
 use rustc_middle::ty::TyCtxt;
-use rustc_span::def_id::CRATE_DEF_INDEX;
 use rustc_span::{sym, Symbol};
 use rustc_target::spec::abi::Abi;
 
@@ -1312,7 +1311,7 @@ impl clean::Visibility {
                 //                 visibility, so it shouldn't matter.
                 let parent_module = find_nearest_parent_module(cx.tcx(), item_did.expect_def_id());
 
-                if vis_did.index == CRATE_DEF_INDEX {
+                if vis_did.is_crate_root() {
                     "pub(crate) ".to_owned()
                 } else if parent_module == Some(vis_did) {
                     // `pub(in foo)` where `foo` is the parent module
@@ -1360,7 +1359,7 @@ impl clean::Visibility {
                 //                 visibility, so it shouldn't matter.
                 let parent_module = find_nearest_parent_module(tcx, item_did);
 
-                if vis_did.index == CRATE_DEF_INDEX {
+                if vis_did.is_crate_root() {
                     "pub(crate) ".to_owned()
                 } else if parent_module == Some(vis_did) {
                     // `pub(in foo)` where `foo` is the parent module
diff --git a/src/librustdoc/json/conversions.rs b/src/librustdoc/json/conversions.rs
index 0b5fb480595..56b02cd8480 100644
--- a/src/librustdoc/json/conversions.rs
+++ b/src/librustdoc/json/conversions.rs
@@ -10,7 +10,6 @@ use std::fmt;
 use rustc_ast::ast;
 use rustc_hir::{def::CtorKind, def_id::DefId};
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_span::def_id::CRATE_DEF_INDEX;
 use rustc_span::Pos;
 use rustc_target::spec::abi::Abi as RustcAbi;
 
@@ -83,7 +82,7 @@ impl JsonRenderer<'_> {
         match v {
             Public => Visibility::Public,
             Inherited => Visibility::Default,
-            Restricted(did) if did.index == CRATE_DEF_INDEX => Visibility::Crate,
+            Restricted(did) if did.is_crate_root() => Visibility::Crate,
             Restricted(did) => Visibility::Restricted {
                 parent: from_item_id(did.into()),
                 path: self.tcx.def_path(did).to_string_no_crate_verbose(),
diff --git a/src/librustdoc/visit_lib.rs b/src/librustdoc/visit_lib.rs
index 5bcec779bc0..9723cdbe334 100644
--- a/src/librustdoc/visit_lib.rs
+++ b/src/librustdoc/visit_lib.rs
@@ -1,6 +1,6 @@
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
+use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_middle::middle::privacy::{AccessLevel, AccessLevels};
 use rustc_middle::ty::TyCtxt;
 
@@ -29,7 +29,7 @@ impl<'a, 'tcx> LibEmbargoVisitor<'a, 'tcx> {
     }
 
     crate fn visit_lib(&mut self, cnum: CrateNum) {
-        let did = DefId { krate: cnum, index: CRATE_DEF_INDEX };
+        let did = cnum.as_def_id();
         self.update(did, Some(AccessLevel::Public));
         self.visit_mod(did);
     }
diff --git a/src/tools/clippy/clippy_lints/src/missing_doc.rs b/src/tools/clippy/clippy_lints/src/missing_doc.rs
index fc0483a929a..5816a95dceb 100644
--- a/src/tools/clippy/clippy_lints/src/missing_doc.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_doc.rs
@@ -10,7 +10,7 @@ use clippy_utils::diagnostics::span_lint;
 use rustc_ast::ast;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::ty;
+use rustc_middle::ty::{self, DefIdTree};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::source_map::Span;
@@ -114,8 +114,8 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
             hir::ItemKind::Fn(..) => {
                 // ignore main()
                 if it.ident.name == sym::main {
-                    let def_key = cx.tcx.hir().def_key(it.def_id);
-                    if def_key.parent == Some(hir::def_id::CRATE_DEF_INDEX) {
+                    let at_root = cx.tcx.local_parent(it.def_id) == Some(CRATE_DEF_ID);
+                    if at_root {
                         return;
                     }
                 }