{"ast_node_type":"variable","tokens":[{"end":89,"kind":"keyword","start":0,"text":"let"}]}
                                    let cause_span = self.tcx.hir_span(*capture_expr_id);
                                UpvarMigrationInfo::CapturingPrecise { source_expr: Some(capture_expr_id), var_name: captured_name } => {
                                    lint.span_label(cause_span, format!("in Rust 2018, this closure captures all of `{}`, but in Rust 2021, it will only capture `{}`",