A modern programming language that makes developers happier.

kotlinlang

so one of the things I want is validation on setters for data classes. This is currently kind've a pain in the butt.
with a data class, you cant override setters, and you cant use properties. AFAIK this is for syntax reasons more than anything, the semantics of `equals` and `copy` should be undisturbed by the fields being backed by properties or explicit getter/setters.

How about:

```
data class MyPOJO(val regular: Boolean, var mutableAlsoRegular: Char){
  constructor val thirdWithExplicitGet: Int get() = TODO();
  constructor val fourthByProperty by someProperty { TODO() }
  constructor var fifth with explicits: String
      get() = TODO()
      set(value) = TODO("$value")
}
```

which would be destructured as a 5-arity, with `equals`/`hashcode` including `third` `fourth` and `fifth`, its `copy()`would include defaulted parameters for the fifth field, and its constructor signature would be `first: X, second: X, fifth: X`