قلنا يصح النذر بصوم يوم النحر، والبيع الفاسد يفيد الملك لعدم القائل بالفصل.
Examples connect the validity of a vow to fast on the day of sacrifice and the legal effect of a defective sale through the no-distinction principle.
The shared underlying question is whether prohibition of a juristic disposition necessarily destroys its legal constitution or can instead render it defective while leaving particular consequences. If one principle governs both branches, reasoning from that common ground is possible.
This does not make the prohibited conduct permissible: legal constitution or effect is distinct from permission to perform the act.