Function rustc_mir_build::thir::pattern::_match::is_useful_specialized

fn is_useful_specialized<'p, 'tcx>(
    cx: &mut MatchCheckCtxt<'p, 'tcx>, 
    matrix: &Matrix<'p, 'tcx>, 
    v: &PatStack<'p, 'tcx>, 
    ctor: Constructor<'tcx>, 
    ty: Ty<'tcx>, 
    witness_preference: WitnessPreference, 
    hir_id: HirId, 
    is_under_guard: bool
) -> Usefulness<'tcx>

A shorthand for the U(S(c, P), S(c, q)) operation from the paper. I.e., is_useful applied to the specialised version of both the pattern matrix P and the new pattern q.