Then Parliament has the right to hold a vote of no confidence next week, and get a government it does have confidence in. Or force a general election.
This appears to be Johnson's gambit:
1) Force a vote of no confidence and lose it.
2) Hope that no interim government can be called.
2a) if it can, accept that A50 may be extended or revoked and then an election fought (before we leave with no deal)
2b) it it can't, plan to fight an election (after we leave with no deal)
3) Promise lots of headline-grabbing populist stuff that is uncosted and won't work in order to win that election.
If you've been paying attention, you'll see that he has already been doing lots of (3). Don't fall for any of those promises, he almost certainly won't follow through on any of them if his past record is anything to go by.