I recently had a script with some t_QFR objects and wanted to take their discriminants. At the time I just did [a,b,c]=Vec(q); b^2-4*a*c but now I see that the inaptly-named poldisc() handles them. I wonder if it would make sense to allow q.disc directly?
As it stands poldisc() handles not only polynomials but most other types, while the member function .disc already handles t_QUAD and other non-vector types.
If this change is advisable*, here is the (brief) change to language/members.c:
member_disc(GEN x) /* discriminant */
long t; GEN y = get_nf(x,&t);
if (y) return nf_get_disc(y);
case typ_Q : return quad_disc(x);
case typ_ELL: return ell_get_disc(x);
default : return poldisc0(x);