{"ast_node_type":"variable","tokens":[{"end":64,"kind":"keyword","start":0,"text":"let"}]}
        let substs = TyBuilder::placeholder_subst(db, trait_id);
        cov_mark::hit!(trait_self_implements_self);
        let trait_ref = TraitRef { trait_id: to_chalk_trait_id(trait_id), substitution: substs };