Musannaf Ibn Abi Shayba 13:1444

Abu Bakr narrated to us, he said: Ibn Abi Za’idah narrated to us, from ‘Abd al-Malik, from ‘Ata’, regarding a man who enters into a salam contract for a known thing for a known term, and if he does not deliver it, then such and such [is due] for another known thing. He said: It is not permissible.