{"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
            let (kind, span) = if let Some(param) = param {
                .and_then(|expected_idx| self.tcx.hir_body(*body).params.get(expected_idx));
                // Try to find earlier invocations of this closure to find if the type mismatch