Function rustc_mir_build::thir::pattern::check_match::check_not_useful

fn check_not_useful<'p, 'tcx>(
    cx: &mut MatchCheckCtxt<'p, 'tcx>, 
    ty: Ty<'tcx>, 
    matrix: &Matrix<'p, 'tcx>, 
    hir_id: HirId
) -> Result<(), Vec<Pat<'tcx>>>