Rollup merge of #144448 - camsteffen:defaultness-impl-trait-only, r=compiler-errors

Limit defaultness query to impl of trait

I separated this out from #144386.

Author: matthiaskrgr

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2124,11 +2124,11 @@ 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) {
                 record!(self.tables.impl_trait_header[def_id] <- header);
 
+                self.tables.defaultness.set_some(def_id.index, tcx.defaultness(def_id));
+
                 let trait_ref = header.trait_ref.instantiate_identity();
                 let simplified_self_ty = fast_reject::simplify_type(
                     self.tcx,

compiler/rustc_ty_utils/src/ty.rs

@@ -80,8 +80,11 @@ 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::Item(hir::Item {
+            kind: hir::ItemKind::Impl(hir::Impl { defaultness, of_trait: Some(_), .. }),
+            ..
+        })
+        | hir::Node::ImplItem(hir::ImplItem { defaultness, .. })
         | hir::Node::TraitItem(hir::TraitItem { defaultness, .. }) => *defaultness,
         node => {
             bug!("`defaultness` called on {:?}", node);