How to extend a data class with toString

Question

I have created a data class

data class Something (
    val a : String,
    val b : Object,
    val c : String
)

as later in my program, I nee

Answer 1

In Kotlin, extension functions cannot override member functions, moreover, they are resolved statically. It implies that if you write an extension function fun Something.toString() = ..., s.toString() won't be resolved to it, because member always wins.

But in your case, nothing stops you from overriding toString inside Something class body, because data classes can have bodies just like regular classes:

data class Something(
    val a: String,
    val b: Any,
    val c: String
) {
    override fun toString(): String = a + b + c
}