Struct rustc_pattern_analysis::pat_column::PatternColumn

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pub struct PatternColumn<'p, Cx: PatCx> {
    patterns: Vec<&'p DeconstructedPat<Cx>>,
}
Expand description

A column of patterns in a match, where a column is the intuitive notion of “subpatterns that inspect the same subvalue/place”. This is used to traverse patterns column-by-column for lints. Despite similarities with the algorithm in crate::usefulness, this does a different traversal. Notably this is linear in the depth of patterns, whereas compute_exhaustiveness_and_usefulness is worst-case exponential (exhaustiveness is NP-complete). The core difference is that we treat sub-columns separately.

This is not used in the usefulness algorithm; only in lints.

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§patterns: Vec<&'p DeconstructedPat<Cx>>

This must not contain an or-pattern. expand_and_push takes care to expand them.

Implementations§

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

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pub fn new(arms: &[MatchArm<'p, Cx>]) -> Self

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fn expand_and_push(&mut self, pat: PatOrWild<'p, Cx>)

Pushes a pattern onto the column, expanding any or-patterns into its subpatterns. Internal method, prefer PatternColumn::new.

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pub fn head_ty(&self) -> Option<&Cx::Ty>

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

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pub fn analyze_ctors( &self, cx: &Cx, ty: &Cx::Ty, ) -> Result<SplitConstructorSet<Cx>, Cx::Error>

Do constructor splitting on the constructors of the column.

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pub fn specialize( &self, cx: &Cx, ty: &Cx::Ty, ctor: &Constructor<Cx>, ) -> Vec<PatternColumn<'p, Cx>>

Does specialization: given a constructor, this takes the patterns from the column that match the constructor, and outputs their fields. This returns one column per field of the constructor. They usually all have the same length (the number of patterns in self that matched ctor), except that we expand or-patterns which may change the lengths.

Trait Implementations§

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impl<'p, Cx: Debug + PatCx> Debug for PatternColumn<'p, Cx>

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'p, Cx> Freeze for PatternColumn<'p, Cx>

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impl<'p, Cx> RefUnwindSafe for PatternColumn<'p, Cx>

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impl<'p, Cx> Send for PatternColumn<'p, Cx>
where <Cx as PatCx>::Ty: Sync, <Cx as PatCx>::PatData: Sync, <Cx as PatCx>::VariantIdx: Sync, <Cx as PatCx>::StrLit: Sync,

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impl<'p, Cx> Sync for PatternColumn<'p, Cx>
where <Cx as PatCx>::Ty: Sync, <Cx as PatCx>::PatData: Sync, <Cx as PatCx>::VariantIdx: Sync, <Cx as PatCx>::StrLit: Sync,

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impl<'p, Cx> Unpin for PatternColumn<'p, Cx>

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impl<'p, Cx> UnwindSafe for PatternColumn<'p, Cx>

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<T> Filterable for T

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fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<P> IntoQueryParam<P> for P

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

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fn upcast(self, interner: I) -> U

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impl<I, T> UpcastFrom<I, T> for T

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fn upcast_from(from: T, _tcx: I) -> T

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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<Tcx, T> Value<Tcx> for T
where Tcx: DepContext,

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default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<'a, T> Captures<'a> for T
where T: ?Sized,

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impl<'a, T> Captures<'a> for T
where T: ?Sized,

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impl<T> ErasedDestructor for T
where T: 'static,

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impl<T> MaybeSendSync for T

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: 24 bytes