Bismillah wa salatu wa salamu ala rasullah.
Shaykh and allama of shias – al-Hilli in his book “Mabadil al Wusul” (p 214) wrote about Qiyas:
اختلف الناس في ذلك، والذي نذهب اليه: انه ليس بحجة
People differ in regards to it, and opinion that we hold on, it is not a proof.
Let me know explain what is qiyas.
Qiyas – mean to establish a rule concerning a new matter by comparing it to a similar matter that has a rule in religion . Imam Ash-Shafi’i said in his book Ar-Risalah: “Qiyas is not permitted when a Khabar (Hadith) exists.” Similar to this saying is what some scholars say: “If Athar (Hadith) exists, Qiyas is abandoned,” and, “There is no Ijtihad where the Nass (text of the Quran or Hadith) exists.”