I submitted the paper to a respectable journal about five months ago. My field is mathematics, and I'm at the postdoc stage of my career.
The proof of one of my theorems is more or less completely wrong. It's not just full of small errors; the approach I use doesn't and can't work. The theorem is actually true, and I have a correct proof now. (I've checked the new proof with senior colleagues--yes, I should have done this before submitting the previous version of the paper, but that's neither here nor there.) For context, this is one of three main results of the paper, but its proof only takes up about two manuscript pages (out of 18 total).
Should I send a corrected version of the paper to the editor, or should I wait for the referee report? For those with experience serving as editors: would an incorrect but correctable proof of a main theorem cause you to reject outright a paper you would otherwise accept, or is this more likely to lead to a recommendation of major revisions? I say correctable because neither the theorem nor the (correct) proof is particularly surprising in the context of the problem, and there's a good chance a referee with experience in the subfield would, upon discovering the mistake, have a rough idea of the correct approach to take. (Which, of course, makes the mistake all the more embarrassing.)