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You must go to his party tomorrow. He would be mad if you didn’t.

You must go to his party tomorrow. He will be mad if you don't.

So both of the sentences with the will and would above are correct, just to clarify one more time?

I have got one more sentence. Would you mind checking it, please?

—I left my wallet while I had lunch. Syam might have taken it.
— I would be mad if he did.

or,

—I left my wallet while I had lunch. Syam might have taken it.
— I would have been mad if he had done it.

Are these two examples correct? Any corrections?