Data class inheritance

Language Design
13

Because library I use works only with data classes contain params with annotations.

I think I understand. As possible example, it can be external dto which has common block of code (for example - self link for output json dtos).

Did you consider interface for this?

E.g. you can have:

interface B {
     @JsonParameter("double_value")
     val field1: Double
}

interface C {
     @JsonParameter("int_value")
     val field2: Int
}

data class A(
      val override field1: Double,
      val override field2: Int,
     @JsonParameter("char_value")
      val field3: Char  
): B, C

?