coercion problem with 0 variable polynomials #7951
Description
sage: R.<x,y> = QQ[]
sage: P = PolynomialRing(QQ,0,'')
sage: P
Multivariate Polynomial Ring in no variables over Rational Field
sage: t = P.random_element()
sage: t
-1
sage: t*x
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/home/burcin/.sage/temp/karr/24426/_home_burcin__sage_init_sage_0.py in <module>()
/home/burcin/sage/sage-4.3.alpha0/local/lib/python2.6/site-packages/sage/structure/element.so in sage.structure.element.RingElement.__mul__ (sage/structure/element.c:10153)()
/home/burcin/sage/sage-4.3.alpha0/local/lib/python2.6/site-packages/sage/structure/coerce.so in sage.structure.coerce.CoercionModel_cache_maps.bin_op (sage/structure/coerce.c:6988)()
TypeError: unsupported operand parent(s) for '*': 'Multivariate Polynomial Ring in no variables over Rational Field' and 'Multivariate Polynomial Ring in x, y over Rational Field'
CC: @malb
Component: basic arithmetic
Author: Burcin Erocal
Reviewer: Robert Bradshaw, Alex Ghitza
Merged: sage-4.3.2.alpha0
Issue created by migration from https://trac.sagemath.org/ticket/7951