# Enum rustc_ast::ast::PatKind

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    pub enum PatKind {
    Show 18 variants    Wild,
        Ident(BindingMode, 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(BindingMode, 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§

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### impl DynSend for PatKind

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### impl DynSync for PatKind

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### impl Freeze for PatKind

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### impl !RefUnwindSafe for PatKind

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### impl !Send for PatKind

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### impl !Sync for PatKind

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### impl Unpin for PatKind

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### impl !UnwindSafe for PatKind

## 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,

## 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: 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