{"ast_node_type":"other","tokens":[{"end":40,"kind":"keyword","start":0,"text":"cx.type_of(dyn_metadata)"}]}
                cx.type_of(dyn_metadata)
                let dyn_metadata = cx.require_lang_item(TraitSolverLangItem::DynMetadata);
                    .instantiate(cx, &[I::GenericArg::from(goal.predicate.self_ty())])