add mapping from DefKind to Target and remove more ItemLikeVisitor impls

Signed-off-by: Miguel Guarniz <mi9uel9@gmail.com>

compiler/rustc_hir/src/target.rs

@@ -7,6 +7,7 @@
 use crate::hir;
 use crate::{Item, ItemKind, TraitItem, TraitItemKind};
 
+use crate::def::DefKind;
 use std::fmt::{self, Display};
 
 #[derive(Copy, Clone, PartialEq, Debug)]
@@ -130,6 +131,29 @@ impl Target {
         }
     }
 
+    pub fn from_def_kind(def_kind: DefKind) -> Target {
+        match def_kind {
+            DefKind::ExternCrate => Target::ExternCrate,
+            DefKind::Use => Target::Use,
+            DefKind::Static(..) => Target::Static,
+            DefKind::Const => Target::Const,
+            DefKind::Fn => Target::Fn,
+            DefKind::Macro(..) => Target::MacroDef,
+            DefKind::Mod => Target::Mod,
+            DefKind::ForeignMod => Target::ForeignMod,
+            DefKind::GlobalAsm => Target::GlobalAsm,
+            DefKind::TyAlias => Target::TyAlias,
+            DefKind::OpaqueTy => Target::OpaqueTy,
+            DefKind::Enum => Target::Enum,
+            DefKind::Struct => Target::Struct,
+            DefKind::Union => Target::Union,
+            DefKind::Trait => Target::Trait,
+            DefKind::TraitAlias => Target::TraitAlias,
+            DefKind::Impl => Target::Impl,
+            _ => panic!("impossible case reached"),
+        }
+    }
+
     pub fn from_trait_item(trait_item: &TraitItem<'_>) -> Target {
         match trait_item.kind {
             TraitItemKind::Const(..) => Target::AssocConst,

compiler/rustc_passes/src/lang_items.rs

@@ -12,8 +12,8 @@ use crate::weak_lang_items;
 
 use rustc_errors::{pluralize, struct_span_err};
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::lang_items::{extract, GenericRequirement, ITEM_REFS};
 use rustc_hir::{HirId, LangItem, LanguageItems, Target};
 use rustc_middle::ty::TyCtxt;
@@ -27,28 +27,6 @@ struct LanguageItemCollector<'tcx> {
     tcx: TyCtxt<'tcx>,
 }
 
-impl<'v, 'tcx> ItemLikeVisitor<'v> for LanguageItemCollector<'tcx> {
-    fn visit_item(&mut self, item: &hir::Item<'_>) {
-        self.check_for_lang(Target::from_item(item), item.hir_id());
-
-        if let hir::ItemKind::Enum(def, ..) = &item.kind {
-            for variant in def.variants {
-                self.check_for_lang(Target::Variant, variant.id);
-            }
-        }
-    }
-
-    fn visit_trait_item(&mut self, trait_item: &hir::TraitItem<'_>) {
-        self.check_for_lang(Target::from_trait_item(trait_item), trait_item.hir_id())
-    }
-
-    fn visit_impl_item(&mut self, impl_item: &hir::ImplItem<'_>) {
-        self.check_for_lang(target_from_impl_item(self.tcx, impl_item), impl_item.hir_id())
-    }
-
-    fn visit_foreign_item(&mut self, _: &hir::ForeignItem<'_>) {}
-}
-
 impl<'tcx> LanguageItemCollector<'tcx> {
     fn new(tcx: TyCtxt<'tcx>) -> LanguageItemCollector<'tcx> {
         LanguageItemCollector { tcx, items: LanguageItems::new() }
@@ -262,18 +240,28 @@ fn get_lang_items(tcx: TyCtxt<'_>, (): ()) -> LanguageItems {
     let crate_items = tcx.hir_crate_items(());
 
     for id in crate_items.items() {
-        let item = tcx.hir().item(id);
-        collector.visit_item(item);
+        collector.check_for_lang(Target::from_def_kind(tcx.hir().def_kind(id.def_id)), id.hir_id());
+
+        if matches!(tcx.hir().def_kind(id.def_id), DefKind::Enum) {
+            let item = tcx.hir().item(id);
+            if let hir::ItemKind::Enum(def, ..) = &item.kind {
+                for variant in def.variants {
+                    collector.check_for_lang(Target::Variant, variant.id);
+                }
+            }
+        }
     }
 
+    // FIXME: avoid calling trait_item() when possible
     for id in crate_items.trait_items() {
         let item = tcx.hir().trait_item(id);
-        collector.visit_trait_item(item);
+        collector.check_for_lang(Target::from_trait_item(item), item.hir_id())
     }
 
+    // FIXME: avoid calling impl_item() when possible
     for id in crate_items.impl_items() {
         let item = tcx.hir().impl_item(id);
-        collector.visit_impl_item(item);
+        collector.check_for_lang(target_from_impl_item(tcx, item), item.hir_id())
     }
 
     // Extract out the found lang items.

compiler/rustc_passes/src/weak_lang_items.rs

@@ -2,20 +2,11 @@
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
-use rustc_hir as hir;
-use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::lang_items::{self, LangItem};
 use rustc_hir::weak_lang_items::WEAK_ITEMS_REFS;
 use rustc_middle::middle::lang_items::required;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::CrateType;
-use rustc_span::symbol::Symbol;
-use rustc_span::Span;
-
-struct Context<'a, 'tcx> {
-    tcx: TyCtxt<'tcx>,
-    items: &'a mut lang_items::LanguageItems,
-}
 
 /// Checks the crate for usage of weak lang items, returning a vector of all the
 /// language items required by this crate, but not defined yet.
@@ -30,10 +21,28 @@ pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>, items: &mut lang_items::LanguageItem
         items.missing.push(LangItem::EhCatchTypeinfo);
     }
 
-    {
-        let mut cx = Context { tcx, items };
-        tcx.hir().visit_all_item_likes(&mut cx.as_deep_visitor());
+    let crate_items = tcx.hir_crate_items(());
+    for id in crate_items.foreign_items() {
+        let attrs = tcx.hir().attrs(id.hir_id());
+        let span = tcx.hir().span(id.hir_id());
+        if let Some((lang_item, _)) = lang_items::extract(attrs) {
+            if let Some(&item) = WEAK_ITEMS_REFS.get(&lang_item) {
+                if items.require(item).is_err() {
+                    items.missing.push(item);
+                }
+            } else {
+                struct_span_err!(
+                    tcx.sess,
+                    span,
+                    E0264,
+                    "unknown external lang item: `{}`",
+                    lang_item
+                )
+                .emit();
+            }
+        }
     }
+
     verify(tcx, items);
 }
 
@@ -80,26 +89,3 @@ fn verify<'tcx>(tcx: TyCtxt<'tcx>, items: &lang_items::LanguageItems) {
         }
     }
 }
-
-impl<'a, 'tcx> Context<'a, 'tcx> {
-    fn register(&mut self, name: Symbol, span: Span) {
-        if let Some(&item) = WEAK_ITEMS_REFS.get(&name) {
-            if self.items.require(item).is_err() {
-                self.items.missing.push(item);
-            }
-        } else {
-            struct_span_err!(self.tcx.sess, span, E0264, "unknown external lang item: `{}`", name)
-                .emit();
-        }
-    }
-}
-
-impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> {
-    fn visit_foreign_item(&mut self, i: &hir::ForeignItem<'_>) {
-        let attrs = self.tcx.hir().attrs(i.hir_id());
-        if let Some((lang_item, _)) = lang_items::extract(attrs) {
-            self.register(lang_item, i.span);
-        }
-        intravisit::walk_foreign_item(self, i)
-    }
-}