title: Kotlin Cast String as String.Companion
body: <p>So I'm new to learning Kotlin, coming from a C# background. I've been messing around with types and a few other things. I'm trying to create a static class of "WalMartGreeters" that can add greeters to a list, and then call a simple static function to display those. My method(s) takes a string argument/string list to add to the mutable string list but when I attempt to add values to it. I get a pre-compilation error saying "expected String.Companion" "got String" I attempt to change it to cast the String as a String.Companion and then it says the cast is illegal. </p>
  
  <p>The predominant error I get is: Exception in thread "main" java.lang.ClassCastException: java.lang.String cannot be cast to kotlin.jvm.internal.StringCompanionObject</p>
  
  <pre><code>fun main(args:Array&lt;String&gt;) {
      walMartGreeter.addTo("Jean")
      walMartGreeter.addTo("Dale")
      walMartGreeter.addTo("Phil")
      walMartGreeter.addTo("Chris")
      walMartGreeter.listTheWholeFam()
  }
  
  class walMartGreeter(val strName:String) {
      companion object classList {
          var prntList = mutableListOf(String)
  
          fun addTo(strNameToAdd:String) {
              prntList.add(strNameToAdd)
          }
  
          fun addTo(listOfNames:List&lt;String&gt;) {
              for (item in listOfNames) {
                  prntList.add(item)
              }
          }
  
          fun listTheWholeFam() {
              //println("All I do is $strName")
              for(item in prntList) {
                  println("Hello, $item!")
              }
              //println("type of mutList: ${mutList.ToString()}")
              if(prntList is MutableList) {
                  println("Yeah, it's a mutableList");
              }
          }
      }
  }
  </code></pre>