Introduce OwnerNode::Crate.

compiler/rustc_ast_lowering/src/lib.rs

@@ -512,8 +512,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         visit::walk_crate(&mut MiscCollector { lctx: &mut self }, c);
         visit::walk_crate(&mut item::ItemLowerer { lctx: &mut self }, c);
 
-        let module = self.lower_mod(&c.items, c.span);
+        let module = self.arena.alloc(self.lower_mod(&c.items, c.span));
         self.lower_attrs(hir::CRATE_HIR_ID, &c.attrs);
+        self.owners.ensure_contains_elem(CRATE_DEF_ID, || None);
+        self.owners[CRATE_DEF_ID] = Some(hir::OwnerNode::Crate(module));
+
         let body_ids = body_ids(&self.bodies);
         let proc_macros =
             c.proc_macros.iter().map(|id| self.node_id_to_hir_id[*id].unwrap()).collect();
@@ -548,7 +551,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
 
         let krate = hir::Crate {
-            item: module,
             non_exported_macro_attrs: self.arena.alloc_from_iter(self.non_exported_macro_attrs),
             owners: self.owners,
             bodies: self.bodies,

compiler/rustc_hir/src/arena.rs

@@ -36,6 +36,7 @@ macro_rules! arena_types {
             [few] llvm_inline_asm: rustc_hir::LlvmInlineAsm<$tcx>,
             [] local: rustc_hir::Local<$tcx>,
             [few] macro_def: rustc_hir::MacroDef<$tcx>,
+            [few] mod_: rustc_hir::Mod<$tcx>,
             [] param: rustc_hir::Param<$tcx>,
             [] pat: rustc_hir::Pat<$tcx>,
             [] path: rustc_hir::Path<$tcx>,

compiler/rustc_hir/src/hir.rs

@@ -1,6 +1,6 @@
 // ignore-tidy-filelength
 use crate::def::{CtorKind, DefKind, Res};
-use crate::def_id::DefId;
+use crate::def_id::{DefId, CRATE_DEF_ID};
 crate use crate::hir_id::{HirId, ItemLocalId};
 use crate::{itemlikevisit, LangItem};
 
@@ -628,7 +628,6 @@ pub struct ModuleItems {
 /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 #[derive(Debug)]
 pub struct Crate<'hir> {
-    pub item: Mod<'hir>,
     // Attributes from non-exported macros, kept only for collecting the library feature list.
     pub non_exported_macro_attrs: &'hir [Attribute],
 
@@ -658,6 +657,10 @@ pub struct Crate<'hir> {
 }
 
 impl Crate<'hir> {
+    pub fn module(&self) -> &'hir Mod<'hir> {
+        if let Some(OwnerNode::Crate(m)) = self.owners[CRATE_DEF_ID] { m } else { panic!() }
+    }
+
     pub fn item(&self, id: ItemId) -> &'hir Item<'hir> {
         self.owners[id.def_id].as_ref().unwrap().expect_item()
     }
@@ -698,7 +701,7 @@ impl Crate<'_> {
                 OwnerNode::ForeignItem(item) => visitor.visit_foreign_item(item),
                 OwnerNode::ImplItem(item) => visitor.visit_impl_item(item),
                 OwnerNode::TraitItem(item) => visitor.visit_trait_item(item),
-                OwnerNode::MacroDef(_) => {}
+                OwnerNode::MacroDef(_) | OwnerNode::Crate(_) => {}
             }
         }
     }
@@ -713,7 +716,7 @@ impl Crate<'_> {
             Some(OwnerNode::ForeignItem(item)) => visitor.visit_foreign_item(item),
             Some(OwnerNode::ImplItem(item)) => visitor.visit_impl_item(item),
             Some(OwnerNode::TraitItem(item)) => visitor.visit_trait_item(item),
-            Some(OwnerNode::MacroDef(_)) | None => {}
+            Some(OwnerNode::MacroDef(_)) | Some(OwnerNode::Crate(_)) | None => {}
         })
     }
 
@@ -2943,16 +2946,29 @@ pub enum OwnerNode<'hir> {
     TraitItem(&'hir TraitItem<'hir>),
     ImplItem(&'hir ImplItem<'hir>),
     MacroDef(&'hir MacroDef<'hir>),
+    Crate(&'hir Mod<'hir>),
 }
 
 impl<'hir> OwnerNode<'hir> {
-    pub fn ident(&self) -> Ident {
+    pub fn ident(&self) -> Option<Ident> {
         match self {
             OwnerNode::Item(Item { ident, .. })
             | OwnerNode::ForeignItem(ForeignItem { ident, .. })
             | OwnerNode::ImplItem(ImplItem { ident, .. })
             | OwnerNode::TraitItem(TraitItem { ident, .. })
-            | OwnerNode::MacroDef(MacroDef { ident, .. }) => *ident,
+            | OwnerNode::MacroDef(MacroDef { ident, .. }) => Some(*ident),
+            OwnerNode::Crate(..) => None,
+        }
+    }
+
+    pub fn span(&self) -> Span {
+        match self {
+            OwnerNode::Item(Item { span, .. })
+            | OwnerNode::ForeignItem(ForeignItem { span, .. })
+            | OwnerNode::ImplItem(ImplItem { span, .. })
+            | OwnerNode::TraitItem(TraitItem { span, .. })
+            | OwnerNode::MacroDef(MacroDef { span, .. })
+            | OwnerNode::Crate(Mod { inner: span, .. }) => *span,
         }
     }
 
@@ -2997,56 +3013,42 @@ impl<'hir> OwnerNode<'hir> {
             | OwnerNode::ImplItem(ImplItem { def_id, .. })
             | OwnerNode::ForeignItem(ForeignItem { def_id, .. })
             | OwnerNode::MacroDef(MacroDef { def_id, .. }) => *def_id,
+            OwnerNode::Crate(..) => crate::CRATE_HIR_ID.owner,
         }
     }
 
     pub fn expect_item(self) -> &'hir Item<'hir> {
         match self {
             OwnerNode::Item(n) => n,
-            OwnerNode::ForeignItem(_)
-            | OwnerNode::ImplItem(_)
-            | OwnerNode::TraitItem(_)
-            | OwnerNode::MacroDef(_) => panic!(),
+            _ => panic!(),
         }
     }
 
     pub fn expect_foreign_item(self) -> &'hir ForeignItem<'hir> {
         match self {
             OwnerNode::ForeignItem(n) => n,
-            OwnerNode::Item(_)
-            | OwnerNode::ImplItem(_)
-            | OwnerNode::TraitItem(_)
-            | OwnerNode::MacroDef(_) => panic!(),
+            _ => panic!(),
         }
     }
 
     pub fn expect_impl_item(self) -> &'hir ImplItem<'hir> {
         match self {
             OwnerNode::ImplItem(n) => n,
-            OwnerNode::ForeignItem(_)
-            | OwnerNode::Item(_)
-            | OwnerNode::TraitItem(_)
-            | OwnerNode::MacroDef(_) => panic!(),
+            _ => panic!(),
         }
     }
 
     pub fn expect_trait_item(self) -> &'hir TraitItem<'hir> {
         match self {
             OwnerNode::TraitItem(n) => n,
-            OwnerNode::ForeignItem(_)
-            | OwnerNode::ImplItem(_)
-            | OwnerNode::Item(_)
-            | OwnerNode::MacroDef(_) => panic!(),
+            _ => panic!(),
         }
     }
 
     pub fn expect_macro_def(self) -> &'hir MacroDef<'hir> {
         match self {
             OwnerNode::MacroDef(n) => n,
-            OwnerNode::ForeignItem(_)
-            | OwnerNode::ImplItem(_)
-            | OwnerNode::TraitItem(_)
-            | OwnerNode::Item(_) => panic!(),
+            _ => panic!(),
         }
     }
 }
@@ -3089,6 +3091,7 @@ impl<'hir> Into<Node<'hir>> for OwnerNode<'hir> {
             OwnerNode::ImplItem(n) => Node::ImplItem(n),
             OwnerNode::TraitItem(n) => Node::TraitItem(n),
             OwnerNode::MacroDef(n) => Node::MacroDef(n),
+            OwnerNode::Crate(n) => Node::Crate(n),
         }
     }
 }
@@ -3221,6 +3224,18 @@ impl<'hir> Node<'hir> {
             _ => Constness::NotConst,
         }
     }
+
+    pub fn as_owner(self) -> Option<OwnerNode<'hir>> {
+        match self {
+            Node::Item(i) => Some(OwnerNode::Item(i)),
+            Node::ForeignItem(i) => Some(OwnerNode::ForeignItem(i)),
+            Node::TraitItem(i) => Some(OwnerNode::TraitItem(i)),
+            Node::ImplItem(i) => Some(OwnerNode::ImplItem(i)),
+            Node::MacroDef(i) => Some(OwnerNode::MacroDef(i)),
+            Node::Crate(i) => Some(OwnerNode::Crate(i)),
+            _ => None,
+        }
+    }
 }
 
 // Some nodes are used a lot. Make sure they don't unintentionally get bigger.

compiler/rustc_hir/src/intravisit.rs

@@ -478,7 +478,8 @@ pub trait Visitor<'v>: Sized {
 
 /// Walks the contents of a crate. See also `Crate::visit_all_items`.
 pub fn walk_crate<'v, V: Visitor<'v>>(visitor: &mut V, krate: &'v Crate<'v>) {
-    visitor.visit_mod(&krate.item, krate.item.inner, CRATE_HIR_ID);
+    let top_mod = krate.module();
+    visitor.visit_mod(top_mod, top_mod.inner, CRATE_HIR_ID);
     walk_list!(visitor, visit_macro_def, krate.exported_macros());
     for (&id, attrs) in krate.attrs.iter() {
         for a in *attrs {

compiler/rustc_hir_pretty/src/lib.rs

@@ -169,7 +169,7 @@ pub fn print_crate<'a>(
     // When printing the AST, we sometimes need to inject `#[no_std]` here.
     // Since you can't compile the HIR, it's not necessary.
 
-    s.print_mod(&krate.item, s.attrs(hir::CRATE_HIR_ID));
+    s.print_mod(&krate.module(), s.attrs(hir::CRATE_HIR_ID));
     s.print_remaining_comments();
     s.s.eof()
 }

compiler/rustc_lint/src/builtin.rs

@@ -568,7 +568,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
     }
 
     fn check_crate(&mut self, cx: &LateContext<'_>, krate: &hir::Crate<'_>) {
-        self.check_missing_docs_attrs(cx, hir::CRATE_HIR_ID, krate.item.inner, "the", "crate");
+        self.check_missing_docs_attrs(cx, hir::CRATE_HIR_ID, krate.module().inner, "the", "crate");
 
         for macro_def in krate.exported_macros() {
             // Non exported macros should be skipped, since `missing_docs` only

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -439,7 +439,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
     fn encode_info_for_items(&mut self) {
         let krate = self.tcx.hir().krate();
-        self.encode_info_for_mod(CRATE_DEF_ID, &krate.item);
+        self.encode_info_for_mod(CRATE_DEF_ID, krate.module());
 
         // Proc-macro crates only export proc-macro items, which are looked
         // up using `proc_macro_data`

compiler/rustc_middle/src/hir/map/collector.rs

@@ -77,23 +77,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
         definitions: &'a definitions::Definitions,
         mut hcx: StableHashingContext<'a>,
     ) -> NodeCollector<'a, 'hir> {
-        let hash = {
-            let Crate {
-                ref item,
-                // These fields are handled separately:
-                non_exported_macro_attrs: _,
-                owners: _,
-                trait_impls: _,
-                bodies: _,
-                body_ids: _,
-                modules: _,
-                proc_macros: _,
-                trait_map: _,
-                attrs: _,
-            } = *krate;
-
-            hash_body(&mut hcx, item)
-        };
+        let hash = hash_body(&mut hcx, krate.module());
 
         let mut collector = NodeCollector {
             arena,
@@ -108,7 +92,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
         };
         collector.insert_entry(
             hir::CRATE_HIR_ID,
-            Entry { parent: hir::CRATE_HIR_ID, node: Node::Crate(&krate.item) },
+            Entry { parent: hir::CRATE_HIR_ID, node: Node::Crate(&krate.module()) },
             hash,
         );
 

compiler/rustc_passes/src/entry.rs

@@ -183,7 +183,7 @@ fn configure_main(tcx: TyCtxt<'_>, visitor: &EntryContext<'_, '_>) -> Option<(De
 }
 
 fn no_main_err(tcx: TyCtxt<'_>, visitor: &EntryContext<'_, '_>) {
-    let sp = tcx.hir().krate().item.inner;
+    let sp = tcx.hir().krate().module().inner;
     if *tcx.sess.parse_sess.reached_eof.borrow() {
         // There's an unclosed brace that made the parser reach `Eof`, we shouldn't complain about
         // the missing `fn main()` then as it might have been hidden inside an unclosed block.

compiler/rustc_passes/src/stability.rs

@@ -732,7 +732,7 @@ fn stability_index(tcx: TyCtxt<'tcx>, (): ()) -> Index<'tcx> {
 
         annotator.annotate(
             hir::CRATE_HIR_ID,
-            krate.item.inner,
+            krate.module().inner,
             None,
             AnnotationKind::Required,
             InheritDeprecation::Yes,
@@ -929,7 +929,7 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
     if tcx.stability().staged_api[&LOCAL_CRATE] {
         let krate = tcx.hir().krate();
         let mut missing = MissingStabilityAnnotations { tcx, access_levels };
-        missing.check_missing_stability(hir::CRATE_HIR_ID, krate.item.inner);
+        missing.check_missing_stability(hir::CRATE_HIR_ID, krate.module().inner);
         intravisit::walk_crate(&mut missing, krate);
         krate.visit_all_item_likes(&mut missing.as_deep_visitor());
     }

compiler/rustc_save_analysis/src/dump_visitor.rs

@@ -146,7 +146,7 @@ impl<'tcx> DumpVisitor<'tcx> {
             },
             crate_root: crate_root.unwrap_or_else(|| "<no source>".to_owned()),
             external_crates: self.save_ctxt.get_external_crates(),
-            span: self.span_from_span(krate.item.inner),
+            span: self.span_from_span(krate.module().inner),
         };
 
         self.dumper.crate_prelude(data);
@@ -1092,11 +1092,12 @@ impl<'tcx> DumpVisitor<'tcx> {
             format!("::{}", self.tcx.def_path_str(self.tcx.hir().local_def_id(id).to_def_id()));
 
         let sm = self.tcx.sess.source_map();
-        let filename = sm.span_to_filename(krate.item.inner);
+        let krate_mod = krate.module();
+        let filename = sm.span_to_filename(krate_mod.inner);
         let data_id = id_from_hir_id(id, &self.save_ctxt);
         let children =
-            krate.item.item_ids.iter().map(|i| id_from_def_id(i.def_id.to_def_id())).collect();
-        let span = self.span_from_span(krate.item.inner);
+            krate_mod.item_ids.iter().map(|i| id_from_def_id(i.def_id.to_def_id())).collect();
+        let span = self.span_from_span(krate_mod.inner);
         let attrs = self.tcx.hir().attrs(id);
 
         self.dumper.dump_def(

src/librustdoc/clean/types.rs

@@ -227,7 +227,7 @@ impl ExternalCrate {
         if root.is_local() {
             tcx.hir()
                 .krate()
-                .item
+                .module()
                 .item_ids
                 .iter()
                 .filter_map(|&id| {
@@ -293,7 +293,7 @@ impl ExternalCrate {
         if root.is_local() {
             tcx.hir()
                 .krate()
-                .item
+                .module()
                 .item_ids
                 .iter()
                 .filter_map(|&id| {

src/librustdoc/doctest.rs

@@ -144,7 +144,7 @@ crate fn run(options: Options) -> Result<(), ErrorReported> {
                 hir_collector.visit_testable(
                     "".to_string(),
                     CRATE_HIR_ID,
-                    krate.item.inner,
+                    krate.module().inner,
                     |this| {
                         intravisit::walk_crate(this, krate);
                     },

src/librustdoc/visit_ast.rs

@@ -72,11 +72,11 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
     }
 
     crate fn visit(mut self, krate: &'tcx hir::Crate<'_>) -> Module<'tcx> {
-        let span = krate.item.inner;
+        let span = krate.module().inner;
         let mut top_level_module = self.visit_mod_contents(
             &Spanned { span, node: hir::VisibilityKind::Public },
             hir::CRATE_HIR_ID,
-            &krate.item,
+            &krate.module(),
             self.cx.tcx.crate_name(LOCAL_CRATE),
         );
         // Attach the crate's exported macros to the top-level module.

src/test/ui-fulldeps/auxiliary/lint-for-crate-rpass.rs

@@ -33,7 +33,7 @@ macro_rules! fake_lint_pass {
                     if !cx.sess().contains_name(attrs, $attr) {
                         cx.lint(CRATE_NOT_OKAY, |lint| {
                              let msg = format!("crate is not marked with #![{}]", $attr);
-                             lint.build(&msg).set_span(krate.item.inner).emit()
+                             lint.build(&msg).set_span(krate.module().inner).emit()
                         });
                     }
                 )*

src/test/ui-fulldeps/auxiliary/lint-for-crate.rs

@@ -31,7 +31,7 @@ impl<'tcx> LateLintPass<'tcx> for Pass {
         if !cx.sess().contains_name(attrs, Symbol::intern("crate_okay")) {
             cx.lint(CRATE_NOT_OKAY, |lint| {
                 lint.build("crate is not marked with #![crate_okay]")
-                    .set_span(krate.item.inner)
+                    .set_span(krate.module().inner)
                     .emit()
             });
         }

src/tools/clippy/clippy_lints/src/missing_doc.rs

@@ -106,7 +106,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
 
     fn check_crate(&mut self, cx: &LateContext<'tcx>, krate: &'tcx hir::Crate<'_>) {
         let attrs = cx.tcx.hir().attrs(hir::CRATE_HIR_ID);
-        self.check_missing_docs_attrs(cx, attrs, krate.item.inner, "the", "crate");
+        self.check_missing_docs_attrs(cx, attrs, krate.module().inner, "the", "crate");
     }
 
     fn check_item(&mut self, cx: &LateContext<'tcx>, it: &'tcx hir::Item<'_>) {