syntax_data: {"ast_node_type":"other","tokens":[{"end":62,"kind":"keyword","start":0,"text":"for"}]}
source_snippet:         for (_, data) in body.basic_blocks.iter_enumerated() {
context_before:         let mut pred_count = IndexVec::from_elem(0u8, &body.basic_blocks);
context_after:             for succ in data.terminator().successors() {