grammar - Exceptions that allow the use of "will" after "if"

This as what I've been able to establish:

The use of "will" after "if" is legal only when any of the following conditions apply:

1. The "will" is used as a verb (equivalent to "want"), for example, "If you will".


2. The "if" can be replaced with a "whether", for example, "I don't know if I will make it on time".

Is each of the two conditions above sufficient to make the use of "will" after "if" legal?

Are there any other cases that I've missed, which make the use of "will" after "if" legal?