syntax_data: {"ast_node_type":"other","tokens":[{"end":51,"kind":"keyword","start":0,"text":"for"}]}
source_snippet:         for block in basic_blocks.indices().rev() {
context_before:         // The only Locations that an insertion changes have already been handled.
context_after:             for statement_index in (0..basic_blocks[block].statements.len()).rev() {