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Merge pull request #262 from joleeee/patch-1

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Minor rewording
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Sunface
2022-07-11 09:34:13 +08:00
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en/src/generics-traits/trait-object.md
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# Trait Object # Trait Object
In [traits chapter](https://practice.rs/generics-traits/traits.html#returning-types-that-implement-traits) we have seen that we can't use `impl Trait` when returning multiple types. In [traits chapter](https://practice.rs/generics-traits/traits.html#returning-types-that-implement-traits) we have seen that we can't use `impl Trait` when returning multiple types.
Also one limitation of arrays is that they can only store elements of one type, yeah, enum is a not bad solution when our items are a fixed set of types in compile time, but trait object are more flexible and powerful here. Another limitation of arrays is that they can only store elements of one type. Using enums is not a bad solution when we have a fixed set of types at compile time, but trait objects would be more flexible and powerful.
## Returning Traits with dyn ## Returning Traits with dyn
The Rust compiler needs to know how much space a function's return type requires. Because the different implementations of a trait probably will need different amounts of memory, this means function need to return a concrete type or the same type when using `impl Trait`, or it can return a trait object with `dyn`. The Rust compiler needs to know how much space a function's return type requires. Because the different implementations of a trait probably uses different amounts of memory, functions need to either return a concrete type or the same type when using `impl Trait`, or return a trait object with `dyn`.
1. 🌟🌟🌟 1. 🌟🌟🌟
```rust,editable ```rust,editable
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} }
``` ```
> You can find the solutions [here](https://github.com/sunface/rust-by-practice)(under the solutions path), but only use it when you need it :) > You can find the solutions [here](https://github.com/sunface/rust-by-practice)(under the solutions path), but only use it when you need it :)