"if you will" future reference.

[metal56]

Anything wrong with this sentence, IYOs?

"If you will be having an abdominal x-ray, be sure laboratory personnel and your doctors know you use this medicine."

http://www.heb.com/yourHEBStore/SD-phar ... 036MG&d2=E

[Stephen Jones]

'will' in these cases is not a straightforward modal but has an element of volition, often the suggestion of perverse volition.

Here, however, it seems to me to be more a case of referring to something in the future that isn't arranged yet.

[metal56]

'will' in these cases is not a straightforward modal but has an element of volition, often the suggestion of perverse volition.

Yes, that's true. Much of the time it has the meaning of "if you insist on/persist..."

Here, however, it seems to me to be more a case of referring to something in the future that isn't arranged yet.

So for you, the "will" is OK in that clause, right?

[Stephen Jones]

yes

[metal56]

1. Look, Sarah, if you will eat chocolate, you'll get spots.

2. Look, Mandy, if you eat chocolate, you'll get spots.

Is it certain that the listener in each sentence eats chocolate?

[Stephen Jones]

It can be presumed in the first one if the sentence stress is "if you will eat chocolate....." but not if it is "If you'll eat chocolate", so I am not sure as to whether that second version is grammatical/idiomatic.

You can't make that presumption in the first sentence.