Add associated_items_for_impl_trait_in_trait query

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -248,6 +248,8 @@ provide! { tcx, def_id, other, cdata,
             .process_decoded(tcx, || panic!("{def_id:?} does not have trait_impl_trait_tys")))
      }
 
+    associated_items_for_impl_trait_in_trait => { table_defaulted_array }
+
     visibility => { cdata.get_visibility(def_id.index) }
     adt_def => { cdata.get_adt_def(def_id.index, tcx) }
     adt_destructor => {

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1129,6 +1129,11 @@ fn should_encode_trait_impl_trait_tys(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     })
 }
 
+// Return `false` to avoid encoding impl trait in trait, while we don't use the query.
+fn should_encode_fn_impl_trait_in_trait<'tcx>(_tcx: TyCtxt<'tcx>, _def_id: DefId) -> bool {
+    false
+}
+
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     fn encode_attrs(&mut self, def_id: LocalDefId) {
         let tcx = self.tcx;
@@ -1211,6 +1216,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             {
                 record!(self.tables.trait_impl_trait_tys[def_id] <- table);
             }
+            if should_encode_fn_impl_trait_in_trait(tcx, def_id) {
+                let table = tcx.associated_items_for_impl_trait_in_trait(def_id);
+                record_defaulted_array!(self.tables.associated_items_for_impl_trait_in_trait[def_id] <- table);
+            }
         }
 
         let inherent_impls = tcx.with_stable_hashing_context(|hcx| {

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -354,6 +354,7 @@ define_tables! {
     explicit_item_bounds: Table<DefIndex, LazyArray<(ty::Predicate<'static>, Span)>>,
     inferred_outlives_of: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
     inherent_impls: Table<DefIndex, LazyArray<DefIndex>>,
+    associated_items_for_impl_trait_in_trait: Table<DefIndex, LazyArray<DefId>>,
 
 - optional:
     attributes: Table<DefIndex, LazyArray<ast::Attribute>>,