I have a little doubt about the tense of the "if" clause, which one of the following phrases is correct :
1) It would be nice if we have dinner tomorrow
2) It would be nice if we had dinner tomorrow
Thanks for your help
PS: The context for the sentence could be that I'm trying to ask somebody out
Sentence #2 fits the normal pattern for a second conditional. However, "would" has many uses other than the pure conditional use. As an expression of expectation or presumption, the use of "would" in sentence #1 with an "if" clause in the present tense is acceptable, IMO.