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src/doc/unstable-book/src/language-features/type-alias-enum-variants.md
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# `type_alias_enum_variants` | ||
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The tracking issue for this feature is: [#49683] | ||
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[#49683]: https://github.com/rust-lang/rust/issues/49683 | ||
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------------------------ | ||
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The `type_alias_enum_variants` feature enables the use of variants on type | ||
aliases that refer to enums, as both a constructor and a pattern. That is, | ||
it allows for the syntax `EnumAlias::Variant`, which behaves exactly the same | ||
as `Enum::Variant` (assuming that `EnumAlias` is an alias for some enum type | ||
`Enum`). | ||
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Note that since `Self` exists as a type alias, this feature also enables the | ||
use of the syntax `Self::Variant` within an impl block for an enum type. | ||
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```rust | ||
#![feature(type_alias_enum_variants)] | ||
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enum Foo { | ||
Bar(i32), | ||
Baz { i: i32 }, | ||
} | ||
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type Alias = Foo; | ||
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fn main() { | ||
let t = Alias::Bar(0); | ||
let t = Alias::Baz { i: 0 }; | ||
match t { | ||
Alias::Bar(_i) => {} | ||
Alias::Baz { i: _i } => {} | ||
} | ||
} | ||
``` |