The fix is in so Trump won’t win on the first vote, then we’ll all going to hear that talking point “the rules are the rules” and then surefire-loser stupidity ensues.
Trump has to do his part, but it should be possible for him to win the nomination if he doesn't say anything else stupid too often. A lot of his comments help by buying free press, but the "punish the mother" comment on abortion hurt his campaign enough to matter. It's recoverable (although we'll keep hearing it until November), but he cannot afford many of those.