A man making a salam contract who says: Whatever is wheat is at such a price

Muhammad bin Zayd (may Allah have mercy on him) said: I said to Sayyiduna Ibn Umar (may Allah be pleased with them both): Sometimes a man makes a salam sale with another for a thousand dirhams or thereabouts, and says: If you give me wheat, the deal is for such an amount; and if you give me barley, it is for such an amount. He (may Allah be pleased with him) said: He should state a separate price for each kind among them. If he gives you the very thing in which you made the salam contract, well and good; otherwise, take back your capital from him.

It is narrated from Sa'id bin Jubayr (may Allah have mercy on him) that if a man, when making a salam sale, says: Whatever wheat you have is for such an amount, and whatever grains you have are for such an amount, then doing so is disliked.

Amir was asked about a salam sale in wheat and barley, on the basis that he may give whichever is easily available. He (may Allah have mercy on him) said: The sale is not suited to this. (It is not valid.)

Ata (may Allah have mercy on him) was asked about a man who makes a salam sale in a specified thing for a specified term: if the seller cannot give him that much, may he give such-and-such a quantity of another specified thing? He (may Allah have mercy on him) said: This is not valid.

Al-Hasan (may Allah have mercy on him) was asked: What about a man who makes a salam sale saying: If it is wheat, it is for such an amount, and if it is barley, it is for such an amount? He (may Allah have mercy on him) disliked it.