Fix pushout of completed fields

[simon-king-jena]

The aim is to fix the following problem.

sage: from sage.categories.pushout import pushout
sage: pushout(Qp(7),RLF)
Traceback (most recent call last):
...
RuntimeError: maximum recursion depth exceeded while calling a Python object

This boils down to change how CompletionFunctor (which is a type of construction functors used both for RLF and Qp(7)) commutes with other construction functors. Currently, it commutes with the fraction field functor and with other completion functors. But in fact it is simply not true that construction functors commute.

Component: coercion

Author: Simon King

Branch/Commit: u/SimonKing/ticket/15329 @ 9d8e737

Reviewer: Marc Mezzarobba

Issue created by migration from https://trac.sagemath.org/ticket/15329

[simon-king-jena]

Branch: u/SimonKing/ticket/15329

[simon-king-jena]

New commits:

[changeset:9d8e737]

Different completion functors must not commute, to fix pushout of completed fields

[simon-king-jena]

Author: Simon King

[simon-king-jena]

Commit: 9d8e737

[mezzarobba]

Reviewer: Marc Mezzarobba

[mezzarobba]

comment:3

Looks good to me.