operator fun iterator(): Iterator

Failed to execute goal org.jetbrains.kotlin:kotlin-maven-plugin:1.3.20:compile (compile) on project xxx: Execution compile of goal org.jetbrains.kotlin:kotlin-maven-plugin:1.3.20:compile failed: A required class was missing while executing org.jetbrains.kotlin:kotlin-maven-plugin:1.3.20:compile: kotlin/reflect/full/KClasses

~/.m2

data class EmailAddress(value: String) {
   init {
       if value is not email regex then error("Invalid value")
   }
}