{"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"UpvarMigrationInfo::CapturingNothing"}]}
                                UpvarMigrationInfo::CapturingNothing { use_span } => {
                                }
                                    lint.span_label(*use_span, format!("in Rust 2018, this causes the closure to capture `{}`, but in Rust 2021, it has no effect",