Multiply between QQ and GF(7) gives exception

[gfurnish]

sage: 1/4*GF(7)['t'](1)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

/home/gfurnish/coercion-test/sage-3.1.alpha2-sage.math-only-x86_64-Linux/<ipython console> in <module>()

/home/gfurnish/coercion-test/sage-3.1.alpha2-sage.math-only-x86_64-Linux/element.pyx in sage.structure.element.RingElement.__mul__ (sage/structure/element.c:9190)()

/home/gfurnish/coercion-test/sage-3.1.alpha2-sage.math-only-x86_64-Linux/coerce.pyx in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:6288)()

TypeError: unsupported operand parent(s) for '*': 'Rational Field' and 'Univariate Polynomial Ring in t over Finite Field of size 7'

This is implied to work by the following doctest in coercion_maps.pyx

            sage: mor = NamedConvertMap(SR, GF(7)[['t']], '_polynomial_')
            sage: mor(x^2/4+1)
            1 + 2*t^2

[robertwb]

I don't think this is a bug, this should *not* work. Conversion != Coercion.

[gfurnish]

So _polynomial_ should also create any underlying conversions needed?

[mabshoff]

Replying to robertwb:

I don't think this is a bug, this should *not* work. Conversion != Coercion.

Hence this is invalid.

Cheers,

Michael