sclass CCI_End extends CharacterClassIterator {
  CharacterClassIterator acceptChar(char c) {
    fail();
  }

  bool canEndHere() {
    true;
  }
  
  bool canAcceptChar(char c) {
    false;
  }
  
  Cl<Char> acceptedChars() { null; }
  CharRange acceptedCharRange() { null; }
  
  CharacterClassIterator cloneCCI() {
    this;
  }
}  

Began life as a copy of #1029558