? bnfinit(x^2-1/2);

  *** bnfinit: Warning: non-monic polynomial in bnfinit, using polredbest.

  *** bnfinit: Warning: non-monic polynomial. Result of the form [nf,c].

  ***   at top-level: bnfinit(x^2-1/2)

  ***                 ^----------------

  *** bnfinit: bug in PARI/GP (Segmentation Fault), please report.