Don't store defaultness for inherent impl items

4 files changed, 9 insertions, 6 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index cb603705ce1..db66938457f 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1725,7 +1725,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         let tcx = self.tcx;
         let item = tcx.associated_item(def_id);
 
-        self.tables.defaultness.set_some(def_id.index, item.defaultness(tcx));
+        if matches!(item.container, AssocContainer::Trait | AssocContainer::TraitImpl(_)) {
+            self.tables.defaultness.set_some(def_id.index, item.defaultness(tcx));
+        }
+
         record!(self.tables.assoc_container[def_id] <- item.container);
 
         if let AssocContainer::Trait = item.container
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 2aa32dfa0d8..0e645a3aae4 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1881,6 +1881,7 @@ rustc_queries! {
     }
 
     /// Returns whether the impl or associated function has the `default` keyword.
+    /// Note: This will ICE on inherent impl items. Consider using `AssocItem::defaultness`.
     query defaultness(def_id: DefId) -> hir::Defaultness {
         desc { |tcx| "looking up whether `{}` has `default`", tcx.def_path_str(def_id) }
         separate_provide_extern
diff --git a/compiler/rustc_middle/src/ty/assoc.rs b/compiler/rustc_middle/src/ty/assoc.rs
index 60181783f9b..768646c7630 100644
--- a/compiler/rustc_middle/src/ty/assoc.rs
+++ b/compiler/rustc_middle/src/ty/assoc.rs
@@ -53,7 +53,10 @@ impl AssocItem {
     ///
     /// [`type_of`]: crate::ty::TyCtxt::type_of
     pub fn defaultness(&self, tcx: TyCtxt<'_>) -> hir::Defaultness {
-        tcx.defaultness(self.def_id)
+        match self.container {
+            AssocContainer::InherentImpl => hir::Defaultness::Final,
+            AssocContainer::Trait | AssocContainer::TraitImpl(_) => tcx.defaultness(self.def_id),
+        }
     }
 
     pub fn expect_trait_impl(&self) -> Result<DefId, ErrorGuaranteed> {
diff --git a/compiler/rustc_ty_utils/src/ty.rs b/compiler/rustc_ty_utils/src/ty.rs
index b3f2bb6d4b5..a5987757dc3 100644
--- a/compiler/rustc_ty_utils/src/ty.rs
+++ b/compiler/rustc_ty_utils/src/ty.rs
@@ -93,10 +93,6 @@ fn defaultness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Defaultness {
             ..
         })
         | hir::Node::TraitItem(hir::TraitItem { defaultness, .. }) => *defaultness,
-        hir::Node::ImplItem(hir::ImplItem {
-            impl_kind: hir::ImplItemImplKind::Inherent { .. },
-            ..
-        }) => hir::Defaultness::Final,
         node => {
             bug!("`defaultness` called on {:?}", node);
         }