static TypeInfection getInfection(TypeView left, TypeView right) {
      if (left.isChanged()) {
        return right.isChanged() ? BOTH_INFECTED : LEFT_INFECTED;
      }
      else {
        return right.isChanged() ? RIGHT_INFECTED : NONE_INFECTED;
      }
    }
static TypeInfection getInfection(TypeView left, TypeView right)