Cascade operator: The expression here has a type of 'void', and therefore can't be used.

Consider the following code

```
model
..sendByEmail.value = false
..onChange = () => setState(() {});
model
..onChange = () => setState(() {})
..sendByEmail.value = false;
```
The first case compiles but the second does not.
`onChange` is a `typedef VoidCallback = void Function();`
`sendByEmail` is an object.
Is this the intended behavior?