Struct rustc_pattern_analysis::usefulness::PatStack

struct PatStack<'p, Cx: PatCx> {
    pats: SmallVec<[PatOrWild<'p, Cx>; 2]>,
    relevant: bool,
}

Represents a pattern-tuple under investigation.

Fields

pats: SmallVec<[PatOrWild<'p, Cx>; 2]>

relevant: bool

Sometimes we know that as far as this row is concerned, the current case is already handled by a different, more general, case. When the case is irrelevant for all rows this allows us to skip a case entirely. This is purely an optimization. See at the top for details.

Implementations

impl<'p, Cx: PatCx> PatStack<'p, Cx>

fn from_pattern(pat: &'p DeconstructedPat<Cx>) -> Self

fn is_empty(&self) -> bool

fn len(&self) -> usize

fn head(&self) -> PatOrWild<'p, Cx>

fn iter(&self) -> impl Iterator<Item = PatOrWild<'p, Cx>> + Captures<'_>

fn expand_or_pat(&self) -> impl Iterator<Item = PatStack<'p, Cx>> + Captures<'_>

fn pop_head_constructor( &self, cx: &Cx, ctor: &Constructor<Cx>, ctor_arity: usize, ctor_is_relevant: bool ) -> Result<PatStack<'p, Cx>, Cx::Error>

This computes specialize(ctor, self). See top of the file for explanations. Only call if ctor.is_covered_by(self.head().ctor()) is true.

Trait Implementations

impl<'p, Cx: PatCx> Clone for PatStack<'p, Cx>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'p, Cx: PatCx> Debug for PatStack<'p, Cx>

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: 32 bytes