You missed various less-direct but often just as effective kinds of questions:

“Can you find the mistake here?”

“Is there a mistake here?”

“Could there be a mistake here?”

“Did you test this part?”

Better still is to be specific:

“What happens if «specific edge case»?”

“I did it that way one time, but ran into «concrete problem».”

“Your way here works just as well, but doesn’t match our conventions.”