# Objective
Trait objects that have `Reflect` as a supertrait cannot be upcast to a `dyn Reflect`.
Attempting something like:
```rust
trait MyTrait: Reflect {
// ...
}
fn foo(value: &dyn MyTrait) {
let reflected = value as &dyn Reflect; // Error!
// ...
}
```
Results in `error[E0658]: trait upcasting coercion is experimental`.
The reason this is important is that a lot of `bevy_reflect` methods require a `&dyn Reflect`. This is trivial with concrete types, but if we don't know the concrete type (we only have the trait object), we can't use these methods. For example, we couldn't create a `ReflectSerializer` for the type since it expects a `&dyn Reflect` value— even though we should be able to.
## Solution
Add `as_reflect` and `as_reflect_mut` to `Reflect` to allow upcasting to a `dyn Reflect`:
```rust
trait MyTrait: Reflect {
// ...
}
fn foo(value: &dyn MyTrait) {
let reflected = value.as_reflect();
// ...
}
```
## Alternatives
We could defer this type of logic to the crate/user. They can add these methods to their trait in the same exact way we do here. The main benefit of doing it ourselves is it makes things convenient for them (especially when using the derive macro).
We could also create an `AsReflect` trait with a blanket impl over all reflected types, however, I could not get that to work for trait objects since they aren't sized.
---
## Changelog
- Added trait method `Reflect::as_reflect(&self)`
- Added trait method `Reflect::as_reflect_mut(&mut self)`
## Migration Guide
- Manual implementors of `Reflect` will need to add implementations for the methods above (this should be pretty easy as most cases just need to return `self`)
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