Could SerializeFor() warn if class doesn't have a serializer?

I have this:

```dart
@SerializersFor([
CellState,
])
final Serializers serializers = _$serializers;
```

But was getting an error about there being no serialiser for `$_CellState`. It took me a while to realise I needed to add the `serializer` to the class:

```dart
static Serializer get serializer => _$cellStateSerializer;
```

Is it possible a warning could be produced when building the code in this case, rather than waiting to throw at runtime?