what am I doing wrong here guys? ``` class Test()...

# getting-started

[poohbar]

what am I doing wrong here guys?

class Test() {
    var l: List<Int> = mutableListOf()

    init {
        l.add(4) // Unresolved
    }
}

[Andreas Sinz]

your l is of type List<Int>, which is read-only in kotlin. use MutableList<Int> instead or completly remove the type. kotlin is able to infer the type of l

[poohbar]

oh... and I guess this is implemented by some weird special cases in the compiler?

[Andreas Sinz]

you are using kotlin.collections.List (https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-list/) by default instead of the Java-List

[cedric]

@poohbar Not sure what you mean by "weird special case".