Limit defaultness to impl of trait

Author: camsteffen

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2124,9 +2124,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             };
             let def_id = id.owner_id.to_def_id();
 
-            self.tables.defaultness.set_some(def_id.index, tcx.defaultness(def_id));
-
             if of_trait && let Some(header) = tcx.impl_trait_header(def_id) {
+                self.tables.defaultness.set_some(def_id.index, tcx.defaultness(def_id));
+
                 record!(self.tables.impl_trait_header[def_id] <- header);
 
                 let trait_ref = header.trait_ref.instantiate_identity();

compiler/rustc_ty_utils/src/ty.rs

@@ -81,7 +81,7 @@ fn sizedness_constraint_for_ty<'tcx>(
 fn defaultness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Defaultness {
     match tcx.hir_node_by_def_id(def_id) {
         hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(impl_), .. }) => impl_.defaultness,
-        hir::Node::ImplItem(hir::ImplItem { defaultness, .. })
+        hir::Node::ImplItem(hir::ImplItem { defaultness, of_trait: Some(_), .. })
         | hir::Node::TraitItem(hir::TraitItem { defaultness, .. }) => *defaultness,
         node => {
             bug!("`defaultness` called on {:?}", node);