syntax_data: {"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"for"}]}
source_snippet:     for UnusedUnsafeWarning { hir_id, block_span, enclosing_unsafe } in warnings {
context_before:     warnings.sort_by_key(|w| w.block_span);
context_after:         let block_span = tcx.sess.source_map().guess_head_span(block_span);