{"ast_node_type":"variable","tokens":[{"end":85,"kind":"keyword","start":0,"text":"let"}]}
            let mcall = make.expr_method_call(cond, make.name_ref("then"), arg_list);
            let arg_list = make.arg_list(Some(make.expr_closure(None, closure_body).into()));
            editor.replace(expr.syntax(), mcall.syntax());