v1 = """
                class Source {
                    val someVal: String = "some"
                    var someVar: String = "some"
                    fun foo(): String = "bar"
                }
            """,
            v2 = """
                class Source {
                    val someVal: String? = null
                    var someVar: String? = null
                    fun foo(): String? = null
                }