I in QQbar returns False

[tmonteil]

As reported on ​this ask question:

sage: I in QQbar
False

This is because in the __contains__ method of the Parent class, the big try...except fails when evaluating the following:

sage: bool(I == QQbar(I))
TypeError: unsupported operand parent(s) for +: 'Number Field in I with defining polynomial x^2 + 1' and 'Algebraic Field'

This early fail does not allow further test to return True.

[rws]

Probably a duplicate of #17984. You might want to voice your opinion there.

[mmezzarobba]

The proper way to fix this issue would be via #12715 and #18036. There has been some progress in this direction, but we're not quite there yet.