Struct rustc_mir_build::thir::pattern::deconstruct_pat::DeconstructedPat

pub(crate) struct DeconstructedPat<'p, 'tcx> {
    ctor: Constructor<'tcx>,
    fields: Fields<'p, 'tcx>,
    ty: Ty<'tcx>,
    span: Span,
    reachable: Cell<bool>,
}

Values and patterns can be represented as a constructor applied to some fields. This represents a pattern in this form. This also uses interior mutability to keep track of whether the pattern has been found reachable during analysis. For this reason they cannot be cloned. A DeconstructedPat will almost always come from user input; the only exception are some Wildcards introduced during specialization.

Fields

ctor: Constructor<'tcx>

fields: Fields<'p, 'tcx>

ty: Ty<'tcx>

span: Span

reachable: Cell<bool>

Implementations

impl<'p, 'tcx> DeconstructedPat<'p, 'tcx>

pub(super) fn wildcard(ty: Ty<'tcx>, span: Span) -> Self

pub(super) fn new( ctor: Constructor<'tcx>, fields: Fields<'p, 'tcx>, ty: Ty<'tcx>, span: Span ) -> Self

pub(crate) fn from_pat(cx: &MatchCheckCtxt<'p, 'tcx>, pat: &Pat<'tcx>) -> Self

Note: the input patterns must have been lowered through super::check_match::MatchVisitor::lower_pattern.

pub(super) fn is_or_pat(&self) -> bool

pub(super) fn flatten_or_pat(&'p self) -> SmallVec<[&'p Self; 1]>

Expand this (possibly-nested) or-pattern into its alternatives.

pub(super) fn ctor(&self) -> &Constructor<'tcx>

pub(super) fn ty(&self) -> Ty<'tcx>

pub(super) fn span(&self) -> Span

pub(super) fn iter_fields<'a>( &'a self ) -> impl Iterator<Item = &'p DeconstructedPat<'p, 'tcx>> + Captures<'a>

pub(super) fn specialize<'a>( &'a self, pcx: &PatCtxt<'_, 'p, 'tcx>, other_ctor: &Constructor<'tcx> ) -> SmallVec<[&'p DeconstructedPat<'p, 'tcx>; 2]>

Specialize this pattern with a constructor. other_ctor can be different from self.ctor, but must be covered by it.

pub(super) fn set_reachable(&self)

We keep track for each pattern if it was ever reachable during the analysis. This is used with unreachable_spans to report unreachable subpatterns arising from or patterns.

pub(super) fn is_reachable(&self) -> bool

pub(super) fn unreachable_spans(&self) -> Vec<Span>

Report the spans of subpatterns that were not reachable, if any.

fn collect_unreachable_spans(&self, spans: &mut Vec<Span>)

Trait Implementations

impl<'p, 'tcx> Debug for DeconstructedPat<'p, 'tcx>

This is mostly copied from the Pat impl. This is best effort and not good enough for a Display impl.

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

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 96 bytes