1 A union expression does not have exactly one field.
3 Erroneous code example:
11 let bird = Bird {}; // error
12 let bird = Bird { pigeon: 0, turtledove: 1 }; // error
15 The key property of unions is that all fields of a union share common storage.
16 As a result, writes to one field of a union can overwrite its other fields, and
17 size of a union is determined by the size of its largest field.
19 You can find more information about the union types in the [Rust reference].
29 let bird = Bird { pigeon: 0 }; // OK
32 [Rust reference]: https://doc.rust-lang.org/reference/items/unions.html