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Say that struct patterns can match union values

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Matthew Woodcraft 2024-02-27 21:52:50 +00:00
parent c6049baeaf
commit 08e5cd4e3c
1 changed files with 6 additions and 3 deletions
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src/patterns.md
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@ -597,8 +597,8 @@ Reference patterns are always irrefutable.
[_OuterAttribute_]: attributes.md
[TUPLE_INDEX]: tokens.md#tuple-index
Struct patterns match struct and enum values that match all criteria defined by its subpatterns.
They are also used to [destructure](#destructuring) a struct or enum value.
Struct patterns match struct, enum, and union values that match all criteria defined by its subpatterns.
They are also used to [destructure](#destructuring) a struct, enum, or union value.
On a struct pattern, the fields are referenced by name, index (in the case of tuple structs) or ignored by use of `..`:
@ -642,7 +642,7 @@ match m {
}
```
If `..` is not used, it is required to match all fields:
If `..` is not used, a struct pattern used to match a struct is required to specify all fields:
```rust
# struct Struct {
@ -661,6 +661,8 @@ match struct_value {
}
```
A struct pattern used to match a union must specify exactly one field (see [Pattern matching on unions]).
The `ref` and/or `mut` _IDENTIFIER_ syntax matches any value and binds it to a variable with the same name as the given field.
```rust
@ -867,6 +869,7 @@ For example, `x @ A(..) | B(..)` will result in an error that `x` is not bound i
[literal expression]: expressions/literal-expr.md
[negating]: expressions/operator-expr.md#negation-operators
[path]: expressions/path-expr.md
[pattern matching on unions]: items/unions.md#pattern-matching-on-unions
[range expressions]: expressions/range-expr.md
[structs]: items/structs.md
[tuples]: types/tuple.md