{"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"///"}]}
    /// Update `self` with the usefulness information found in `row`.
impl<'p, Cx: PatCx> BranchPatUsefulness<'p, Cx> {
    fn update(&mut self, row: &MatrixRow<'p, Cx>, matrix: &Matrix<'p, Cx>) {