creation of relative number fields when defining polynomial not integral no longer broken #4781
Description
sage: K.<a> = NumberField(x^2 + 1)
sage: L.<b> = NumberField(K['y'].0^2 + 1/2)
---------------------------------------------------------------------------
PariError Traceback (most recent call last)
/Users/wstein/sage/build/sage-3.2.2.alpha0/<ipython console> in <module>()
/Users/wstein/sage/build/sage-3.2.2.alpha0/local/lib/python2.5/site-packages/sage/rings/number_field/number_field.pyc in NumberField(polynomial, name, check, names, cache, embedding)
374
375 if isinstance(R, NumberField_generic):
--> 376 S = R.extension(polynomial, name, check=check)
377 if cache:
378 _nf_cache[key] = weakref.ref(S)
/Users/wstein/sage/build/sage-3.2.2.alpha0/local/lib/python2.5/site-packages/sage/rings/number_field/number_field.pyc in extension(self, poly, name, names, check, embedding)
2570 if name is None:
2571 raise TypeError, "the variable name must be specified."
-> 2572 return NumberField_relative(self, poly, str(name), check=check, embedding=embedding)
2573
2574 def factor(self, n):
/Users/wstein/sage/build/sage-3.2.2.alpha0/local/lib/python2.5/site-packages/sage/rings/number_field/number_field.pyc in __init__(self, base, polynomial, name, latex_name, names, check, embedding)
4567
4568 self.__pari_relative_polynomial = pari(str(polynomial_y))
-> 4569 self.__rnf = self.__base_nf.rnfinit(self.__pari_relative_polynomial)
4570
4571 self.__base_field = base
/Users/wstein/sage/build/sage-3.2.2.alpha0/local/lib/python2.5/site-packages/sage/libs/pari/gen.so in sage.libs.pari.gen._pari_trap (sage/libs/pari/gen.c:38578)()
PariError: impossible inverse modulo: (36)
> /Users/wstein/sage/build/sage-3.2.2.alpha0/gen.pyx(8050)sage.libs.pari.gen._pari_trap (sage/libs/pari/gen.c:38578)()
Component: number fields
Issue created by migration from https://trac.sagemath.org/ticket/4781