@Override
  default boolean mayAlias(DfType otherType) {
    if (isLocal() || otherType.isLocal()) return false;
    if (otherType.meet(this) != BOTTOM) {
      // possible aliasing
      return true;
    }
    if (SpecialField.COLLECTION_SIZE.isMyQualifierType(otherType) &&
        SpecialField.COLLECTION_SIZE.isMyQualifierType(this)) {
      // Collection size is sometimes derived from another (incompatible) collection
      // e.g. keySet Set size is affected by Map size.
      return true;
    }
    return false;
  }
@Override
  default boolean mayAlias(DfType otherType)