[NTG-context] Check if two paths intersect in Metafun

Hi, list. I've got a question about paths and intersections. The following: \starttext \startMPpage path p[]; p[1] = fullcircle scaled 2cm; p[2] = unitsquare shifted (4cm,6cm); if (known (p[1] intersectionpoint p[2])): draw textext("yes"); else: draw textext("no"); fi; \stopMPpage \stoptext yields an error message: "The paths don't intersect". Is there a way to intercept this error message and trigger an action instead? Thank you in advance. Best regards, Jairo