Enum rustc_mir_build::thir::pattern::_match::Usefulness

pub(crate) enum Usefulness<'tcx> {
    Useful(Vec<FxHashSet<Span>>),
    UsefulWithWitness(Vec<Witness<'tcx>>),
    NotUseful,
}

Variants

Useful(Vec<FxHashSet<Span>>)

Carries, for each column in the matrix, a set of sub-branches that have been found to be unreachable. Used only in the presence of or-patterns, otherwise it stays empty.

UsefulWithWitness(Vec<Witness<'tcx>>)

Carries a list of witnesses of non-exhaustiveness.

NotUseful

Implementations

impl<'tcx> Usefulness<'tcx>

pub(in thir::pattern::_match) fn new_useful(
    preference: WitnessPreference
) -> Self

pub(in thir::pattern::_match) fn is_useful(
    &self
) -> bool

pub(in thir::pattern::_match) fn apply_constructor<'p>(
    self,
    pcx: PatCtxt<'_, 'p, 'tcx>,
    ctor: &Constructor<'tcx>,
    ctor_wild_subpatterns: &Fields<'p, 'tcx>
) -> Self

Trait Implementations

impl<'tcx> Clone for Usefulness<'tcx>

pub fn clone(&self) -> Usefulness<'tcx>

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'tcx> Debug for Usefulness<'tcx>

pub fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.