pub enum PatKind {
Show 15 variants Wild, Ident(BindingModeIdentOption<P<Pat>>), Struct(Option<QSelf>, PathVec<PatField>, bool), TupleStruct(Option<QSelf>, PathVec<P<Pat>>), Or(Vec<P<Pat>>), Path(Option<QSelf>, Path), Tuple(Vec<P<Pat>>), Box(P<Pat>), Ref(P<Pat>, Mutability), Lit(P<Expr>), Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>), Slice(Vec<P<Pat>>), Rest, Paren(P<Pat>), MacCall(MacCall),
}
Expand description

All the different flavors of pattern that Rust recognizes.

Variants

Wild

Represents a wildcard pattern (_).

Ident(BindingModeIdentOption<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.

Struct(Option<QSelf>, PathVec<PatField>, bool)

A struct or struct variant pattern (e.g., Variant {x, y, ..}). The bool is true in the presence of a ...

TupleStruct(Option<QSelf>, PathVec<P<Pat>>)

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

Or(Vec<P<Pat>>)

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

Path(Option<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.

Tuple(Vec<P<Pat>>)

A tuple pattern ((a, b)).

Box(P<Pat>)

A box pattern.

Ref(P<Pat>, Mutability)

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

Lit(P<Expr>)

A literal.

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

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

Slice(Vec<P<Pat>>)

A slice pattern [a, b, c].

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.

Paren(P<Pat>)

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

MacCall(MacCall)

A macro pattern; pre-expansion.

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

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: 96 bytes

Size for each variant:

  • Wild: 0 bytes
  • Ident: 23 bytes
  • Struct: 95 bytes
  • TupleStruct: 95 bytes
  • Or: 31 bytes
  • Path: 71 bytes
  • Tuple: 31 bytes
  • Box: 15 bytes
  • Ref: 15 bytes
  • Lit: 15 bytes
  • Range: 31 bytes
  • Slice: 31 bytes
  • Rest: 0 bytes
  • Paren: 15 bytes
  • MacCall: 71 bytes