{"ast_node_type":"variable","tokens":[{"end":63,"kind":"keyword","start":0,"text":"let"}]}
        let trait_sig = self.db.type_alias_signature(alias_id);
        let alias_id = from_assoc_type_id(assoc_type_id);
        hir_def::ImplId::from_chalk(self.db, impl_id).impl_items(self.db).items.iter().find_map(