pub enum PatKind<'tcx> {
    Wild,
    AscribeUserType {
        ascription: Ascription<'tcx>,
        subpattern: Pat<'tcx>,
    },
    Binding {
        mutability: Mutability,
        name: Symbol,
        mode: BindingMode,
        var: HirId,
        ty: Ty<'tcx>,
        subpattern: Option<Pat<'tcx>>,
        is_primary: bool,
    },
    Variant {
        adt_def: &'tcx AdtDef,
        substs: SubstsRef<'tcx>,
        variant_index: VariantIdx,
        subpatterns: Vec<FieldPat<'tcx>>,
    },
    Leaf {
        subpatterns: Vec<FieldPat<'tcx>>,
    },
    Deref {
        subpattern: Pat<'tcx>,
    },
    Constant {
        value: &'tcx Const<'tcx>,
    },
    Range(PatRange<'tcx>),
    Slice {
        prefix: Vec<Pat<'tcx>>,
        slice: Option<Pat<'tcx>>,
        suffix: Vec<Pat<'tcx>>,
    },
    Array {
        prefix: Vec<Pat<'tcx>>,
        slice: Option<Pat<'tcx>>,
        suffix: Vec<Pat<'tcx>>,
    },
    Or {
        pats: Vec<Pat<'tcx>>,
    },
}

Variants

Wild

A wildward pattern: _.

AscribeUserType

Fields

ascription: Ascription<'tcx>
subpattern: Pat<'tcx>

Binding

Fields

mutability: Mutability
name: Symbol
var: HirId
ty: Ty<'tcx>
subpattern: Option<Pat<'tcx>>
is_primary: bool

Is this the leftmost occurrence of the binding, i.e., is var the HirId of this pattern?

x, ref x, x @ P, etc.

Variant

Fields

adt_def: &'tcx AdtDef
substs: SubstsRef<'tcx>
variant_index: VariantIdx
subpatterns: Vec<FieldPat<'tcx>>

Foo(...) or Foo{...} or Foo, where Foo is a variant name from an ADT with multiple variants.

Leaf

Fields

subpatterns: Vec<FieldPat<'tcx>>

(...), Foo(...), Foo{...}, or Foo, where Foo is a variant name from an ADT with a single variant.

Deref

Fields

subpattern: Pat<'tcx>

box P, &P, &mut P, etc.

Constant

Fields

value: &'tcx Const<'tcx>

One of the following:

  • &str, which will be handled as a string pattern and thus exhaustiveness checking will detect if you use the same string twice in different patterns.
  • integer, bool, char or float, which will be handled by exhaustivenes to cover exactly its own value, similar to &str, but these values are much simpler.
  • Opaque constants, that must not be matched structurally. So anything that does not derive PartialEq and Eq.

Range(PatRange<'tcx>)

Slice

Fields

prefix: Vec<Pat<'tcx>>
slice: Option<Pat<'tcx>>
suffix: Vec<Pat<'tcx>>

Matches against a slice, checking the length and extracting elements. irrefutable when there is a slice pattern and both prefix and suffix are empty. e.g., &[ref xs @ ..].

Array

Fields

prefix: Vec<Pat<'tcx>>
slice: Option<Pat<'tcx>>
suffix: Vec<Pat<'tcx>>

Fixed match against an array; irrefutable.

Or

Fields

pats: Vec<Pat<'tcx>>

An or-pattern, e.g. p | q. Invariant: pats.len() >= 2.

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

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

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

This method turns the parameters of a DepNodeConstructor into an opaque Fingerprint to be used in DepNode. Not all DepNodeParams support being turned into a Fingerprint (they don’t need to if the corresponding DepNode is anonymous). Read more

This method tries to recover the query key from the given DepNode, something which is needed when forcing DepNodes during red-green evaluation. The query system will only call this method if fingerprint_style() is not FingerprintStyle::Opaque. It is always valid to return None here, in which case incremental compilation will treat the query as having changed instead of forcing it. Read more

Performs the conversion.

Performs the conversion.

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: 104 bytes

Size for each variant:

  • Wild: 0 bytes
  • AscribeUserType: 103 bytes
  • Binding: 47 bytes
  • Variant: 47 bytes
  • Leaf: 31 bytes
  • Deref: 31 bytes
  • Constant: 15 bytes
  • Range: 31 bytes
  • Slice: 79 bytes
  • Array: 79 bytes
  • Or: 31 bytes