QQbar doesn't use canonical coercion for comparison

[robertwb]

sage: QQbar(2) == GF(7)(2)
BOOM

Should be False.

Component: basic arithmetic

Keywords: QQbar comparison

Author: Robert Bradshaw

Reviewer: John Cremona

Merged: sage-4.3.4.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/7984

[robertwb]

Attachment: 7984-qqbar-cmp.patch.gz

[wjp]

comment:1

This patch depends on #4621 but seems to break the doctest added by that patch.

[robertwb]

comment:2

This patch is correct, the one at #4621 is wrong.

[JohnCremona]

Author: Robert Bradshaw

[JohnCremona]

comment:3

This one looks good to me. However, when testing #4621 I noticed that this:

F.<a>= NumberField(x^2-2)
RR(a)

causes an infinite recursion, which is not good, but not caused by this patch.

I am giving this a positive review, and letting #4621 be sorted out after, also the issue above. Perhaps rwb would like to open a ticket for that unless it is already covered by one?

[JohnCremona]

Changed keywords from none to QQbar comparison

[JohnCremona]

Reviewer: John Cremona