Enum rustc_ast::ast::PatKind

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pub enum PatKind {
Show 18 variants Wild, Ident(BindingAnnotation, Ident, Option<P<Pat>>), Struct(Option<P<QSelf>>, Path, ThinVec<PatField>, PatFieldsRest), TupleStruct(Option<P<QSelf>>, Path, ThinVec<P<Pat>>), Or(ThinVec<P<Pat>>), Path(Option<P<QSelf>>, Path), Tuple(ThinVec<P<Pat>>), Box(P<Pat>), Deref(P<Pat>), Ref(P<Pat>, Mutability), Lit(P<Expr>), Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>), Slice(ThinVec<P<Pat>>), Rest, Never, Paren(P<Pat>), MacCall(P<MacCall>), Err(ErrorGuaranteed),
}
Expand description

All the different flavors of pattern that Rust recognizes.

Variants§

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Wild

Represents a wildcard pattern (_).

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Ident(BindingAnnotation, Ident, Option<P<Pat>>)

A PatKind::Ident may either be a new bound variable (ref mut binding @ OPT_SUBPATTERN), or a unit struct/variant pattern, or a const pattern (in the last two cases the third field must be None). Disambiguation cannot be done with parser alone, so it happens during name resolution.

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Struct(Option<P<QSelf>>, Path, ThinVec<PatField>, PatFieldsRest)

A struct or struct variant pattern (e.g., Variant {x, y, ..}).

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TupleStruct(Option<P<QSelf>>, Path, ThinVec<P<Pat>>)

A tuple struct/variant pattern (Variant(x, y, .., z)).

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Or(ThinVec<P<Pat>>)

An or-pattern A | B | C. Invariant: pats.len() >= 2.

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Path(Option<P<QSelf>>, Path)

A possibly qualified path pattern. Unqualified path patterns A::B::C can legally refer to variants, structs, constants or associated constants. Qualified path patterns <A>::B::C/<A as Trait>::B::C can only legally refer to associated constants.

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Tuple(ThinVec<P<Pat>>)

A tuple pattern ((a, b)).

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Box(P<Pat>)

A box pattern.

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Deref(P<Pat>)

A deref pattern (currently deref!() macro-based syntax).

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Ref(P<Pat>, Mutability)

A reference pattern (e.g., &mut (a, b)).

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Lit(P<Expr>)

A literal.

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Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>)

A range pattern (e.g., 1...2, 1..2, 1.., ..2, 1..=2, ..=2).

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Slice(ThinVec<P<Pat>>)

A slice pattern [a, b, c].

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Rest

A rest pattern ...

Syntactically it is valid anywhere.

Semantically however, it only has meaning immediately inside:

  • a slice pattern: [a, .., b],
  • a binding pattern immediately inside a slice pattern: [a, r @ ..],
  • a tuple pattern: (a, .., b),
  • a tuple struct/variant pattern: $path(a, .., b).

In all of these cases, an additional restriction applies, only one rest pattern may occur in the pattern sequences.

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Never

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Paren(P<Pat>)

Parentheses in patterns used for grouping (i.e., (PAT)).

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MacCall(P<MacCall>)

A macro pattern; pre-expansion.

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Err(ErrorGuaranteed)

Placeholder for a pattern that wasn’t syntactically well formed in some way.

Trait Implementations§

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impl Clone for PatKind

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fn clone(&self) -> PatKind

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 Debug for PatKind

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

Formats the value using the given formatter. Read more
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impl<__D: SpanDecoder> Decodable<__D> for PatKind

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fn decode(__decoder: &mut __D) -> Self

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impl<__E: SpanEncoder> Encodable<__E> for PatKind

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fn encode(&self, __encoder: &mut __E)

Auto Trait Implementations§

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> 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> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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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<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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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: 48 bytes

Size for each variant:

  • Wild: 0 bytes
  • Ident: 23 bytes
  • Struct: 47 bytes
  • TupleStruct: 47 bytes
  • Or: 15 bytes
  • Path: 39 bytes
  • Tuple: 15 bytes
  • Box: 15 bytes
  • Deref: 15 bytes
  • Ref: 15 bytes
  • Lit: 15 bytes
  • Range: 31 bytes
  • Slice: 15 bytes
  • Rest: 0 bytes
  • Never: 0 bytes
  • Paren: 15 bytes
  • MacCall: 15 bytes
  • Err: 0 bytes