void addSubtype(PsiType t) {
      if (t != null) {
        if (myType == null) {
          myType = t;
        }
        else {
          if (!myType.isAssignableFrom(t)) {
            if (t.isAssignableFrom(myType)) {
              myType = t;
            }
            else {
              myType = TypesUtil.getLeastUpperBound(myType, t, myManager);
            }
          }
        }
      }
    }
void addSubtype(PsiType t)