when you have done

Youmay not use any of Future tenses after "when". So, though the meaning is future, you must use the Present Perfect.

I think this generalization is not entirely accurate. What if I say this?

Tom's flight left at this morning and I beleive he will have arrived when you go to bed. Can you call him to make sure?

Goodman,

Buzel said after "when", meaning in the when clause. Your example has will, but not after "when", i.e., not in the when clause.

Nevertheless, Buzel's generalization is not entirely accurate, but for a different reason!
Do you know why? (Think indirect questions.)

Ok how about:

Tom's flight left San Francisco International Airport at six o’clock this morning and I beleive when you go to bed, he will have arrived Hong Kong . Can you call him to make sure?

Indirect question? um... does it have anything to do with "tag"?

No. You've placed will in the main clause again, not in the when clause, so it's OK.
The "wrong" version would have when you will go to bed, he ...

If that same clause is an indirect question, it's OK, however:

No one can guess when you will go to bed.

So the rule of not combining when with will in the s

BuzelYou may not use any of Future tenses after "when". So, though the meaning is future, you must use the Present Perfect.

This is not a mandatory rule. It's something which is often done (thus, to me, optional), per Swan.

It's tense simplification where in subordinate claus

Here's an indirect question with when and when, a case mentioned by CJ:
--------
From the UK Parliament:

Mr. Cartwright : To ask the Secretary of State for the Home
Department , pursuant to his answer of 13 June, Official Report,
columns 367 -8, to the hon. Member for Woolwich, when he wi

This is not a mandatory rule. It's something which is often done (thus, to me, optional), per Swan.

Which part is not mandatory? I may have misunderstood, but I'm assuming the rule you are referring to is: will cannot be used in a when clause where when is an adverbial conjunction. I don't believe there's any

Thank you for your amendments, guys.

My manual says that there is a method using which it is in practice easier to define whether a Future tense must be used:

if "when" means "when exactly", i.e. a month, day, hour etc., and the logical accent can be made on "when", then a Future tense is used.

I don't know when he will come.

no idea when i will g

CalifJim

This is not a mandatory rule. It's something which is often done (thus, to me, optional), per Swan.

Which part is not mandatory? I may have misunderstood, but I'm assuming the rule you are referring to is: will cannot be used in a when clause where when is an adverbial conjunction.