{"ast_node_type":"function","tokens":[{"end":88,"kind":"keyword","start":0,"text":"fn"}]}
    fn visit_basic_block_data(&mut self, bb: BasicBlock, block: &BasicBlockData<'tcx>) {
impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
        trace!("visit_basic_block_data: bb={:?} is_cleanup={:?}", bb, block.is_cleanup);