syntax_data: {"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:             if let Usefulness::Useful(redundant_subpats) = is_useful
context_before:         for (arm, is_useful) in report.arm_usefulness.iter() {
context_after:                 && !redundant_subpats.is_empty()