<passing array to functional interface but get (Ar...

# stackoverflow

[user]

passing array to functional interface but get (Array&lt;out TypeVariable(T)&gt;) -&gt; Array&lt;out TypeVariable(T)&gt;? type mismatch
val changeFirstElement = VarargsFunction { ss: Array ->

ss[0] = ss[0]!! + " world"

ss

}

val params = arrayOf("hello")

}

fun interface VarargsFunction {

fun apply(vararg t: T): Array?

}

I get this following exception: Type mismatch: inferred type is (Array) -> Array? but (Array) -> Array? was expected
Any suggestion why is this exception and how to resolve it? Thanks
Playground link https://pl.kotl.in/kBwQZlCZj