{"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"branch_usefulness:"}]}
    branch_usefulness: FxHashMap<PatId, BranchPatUsefulness<'p, Cx>>,
    /// pattern" at [`BranchPatUsefulness`]).
    // Ideally this field would have type `Limit`, but this crate is used by