MPC complex numbers and the symbolic i cannot be added

[jpflori]

With the current interface to the MPC library, you cannot add the symbolic i and MPC complex numbers:

sage: from sage.rings.complex_mpc import MPComplexField
sage: MPC = MPComplexField()
sage: MPC(1) + SR(i)
Traceback (most recent call last)
...
TypeError: unsupported operand parent(s) for '+':
'Complex Field with 53 bits of precision' and 'Symbolic Ring'
sage: SR(i) + MPC(1)
Traceback (most recent call last)
...
TypeError: unsupported operand parent(s) for '+':
'Symbolic Ring' and 'Complex Field with 53 bits of precision'

This works with "usual" complex numbers:

sage: CC(1) + SR(i)
1.00000000000000 + 1.00000000000000*I

and with the "number-field" version of i
(now the default after #18036):

sage: MPC(1) + i
1.00000000000000 + 1.00000000000000*I

CC: @nexttime @slel

Component: coercion

Keywords: mpc complex numbers multiprecision.org

Issue created by migration from https://trac.sagemath.org/ticket/11808

[slel]

comment:7

Updating ticket description after #18036 was merged in 9.3.beta2.

This, which was failing in the original report, now works:

sage: MPC(1) + i
1.00000000000000 + 1.00000000000000*I

but this still fails:

sage: MPC(1) + SR(i)