{"ast_node_type":"variable","tokens":[{"end":69,"kind":"keyword","start":0,"text":"let"}]}
    let mut result: ArenaMap<BasicBlockId, ArenaMap<LocalId, bool>> =
) -> ArenaMap<BasicBlockId, ArenaMap<LocalId, bool>> {
        body.basic_blocks.iter().map(|it| (it.0, ArenaMap::default())).collect();