{"ast_node_type":"other","tokens":[{"end":74,"kind":"keyword","start":0,"text":")"}]}
    ) -> chalk_ir::Binders<rust_ir::FnDefInputsAndOutputDatum<Interner>> {
        substs: &chalk_ir::Substitution<Interner>,
        let sig_ty = ClosureSubst(substs).sig_ty();