Struct rustc_pattern_analysis::usefulness::Matrix

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struct Matrix<'p, Cx: PatCx> {
    rows: Vec<MatrixRow<'p, Cx>>,
    place_info: SmallVec<[PlaceInfo<Cx>; 2]>,
    wildcard_row_is_relevant: bool,
}
Expand description

A 2D matrix. Represents a list of pattern-tuples under investigation.

Invariant: each row must have the same length, and each column must have the same type.

Invariant: the first column must not contain or-patterns. This is handled by Matrix::push.

In fact each column corresponds to a place inside the scrutinee of the match. E.g. after specializing (,) and Some on a pattern of type (Option<u32>, bool), the first column of the matrix will correspond to scrutinee.0.Some.0 and the second column to scrutinee.1.

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§rows: Vec<MatrixRow<'p, Cx>>

Vector of rows. The rows must form a rectangular 2D array. Moreover, all the patterns of each column must have the same type. Each column corresponds to a place within the scrutinee.

§place_info: SmallVec<[PlaceInfo<Cx>; 2]>

Track info about each place. Each place corresponds to a column in rows, and their types must match.

§wildcard_row_is_relevant: bool

Track whether the virtual wildcard row used to compute exhaustiveness is relevant. See top of the file for details on relevancy.

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

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fn push(&mut self, row: MatrixRow<'p, Cx>)

Pushes a new row to the matrix. Internal method, prefer Matrix::new.

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fn new( arms: &[MatchArm<'p, Cx>], scrut_ty: Cx::Ty, scrut_validity: PlaceValidity, ) -> Self

Build a new matrix from an iterator of MatchArms.

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fn head_place(&self) -> Option<&PlaceInfo<Cx>>

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fn column_count(&self) -> usize

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fn rows( &self, ) -> impl Iterator<Item = &MatrixRow<'p, Cx>> + Clone + DoubleEndedIterator + ExactSizeIterator

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fn rows_mut( &mut self, ) -> impl Iterator<Item = &mut MatrixRow<'p, Cx>> + DoubleEndedIterator + ExactSizeIterator

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

Iterate over the first pattern of each row.

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fn specialize_constructor( &self, pcx: &PlaceCtxt<'_, Cx>, ctor: &Constructor<Cx>, ctor_is_relevant: bool, ) -> Result<Matrix<'p, Cx>, Cx::Error>

This computes specialize(ctor, self). See top of the file for explanations.

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fn unspecialize(&mut self, specialized: Self)

Recover row usefulness and intersection information from a processed specialized matrix. specialized must come from self.specialize_constructor.

Trait Implementations§

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impl<'p, Cx: Clone + PatCx> Clone for Matrix<'p, Cx>

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fn clone(&self) -> Matrix<'p, Cx>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'p, Cx: PatCx> Debug for Matrix<'p, Cx>

Pretty-printer for matrices of patterns, example:

+ _     + []                +
+ true  + [First]           +
+ true  + [Second(true)]    +
+ false + [_]               +
+ _     + [_, _, tail @ ..] +
| ✓     | ?                 | // validity
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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 Matrix<'p, Cx>
where <Cx as PatCx>::Ty: Freeze,

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

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impl<'p, Cx> Send for Matrix<'p, Cx>
where <Cx as PatCx>::Ty: Send + 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 Matrix<'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 Matrix<'p, Cx>
where <Cx as PatCx>::Ty: Unpin,

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impl<'p, Cx> UnwindSafe for Matrix<'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> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. 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> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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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: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.