Implement assumed_wf_types for RPITITs' implementations

compiler/rustc_middle/src/query/mod.rs

@@ -885,6 +885,13 @@ rustc_queries! {
         desc { |tcx| "computing the implied bounds of `{}`", tcx.def_path_str(key) }
     }
 
+    /// We need to store the assumed_wf_types for an RPITIT so that impls of foreign
+    /// traits with return-position impl trait in traits can inherit the right wf types.
+    query assumed_wf_types_for_rpitit(key: DefId) -> &'tcx [(Ty<'tcx>, Span)] {
+        desc { |tcx| "computing the implied bounds of `{}`", tcx.def_path_str(key) }
+        separate_provide_extern
+    }
+
     /// Computes the signature of the function.
     query fn_sig(key: DefId) -> ty::EarlyBinder<ty::PolyFnSig<'tcx>> {
         desc { |tcx| "computing function signature of `{}`", tcx.def_path_str(key) }