"You ought not to combine being resolved to eat no ice cream with acting to eat this ice cream"
"You ought not to combine being resolved to eat no ice cream with acting to eat this ice cream"
"Eat no ice cream" is logically inconsistent with "Eat this ice cream now."
So, by the rationality axiom, you ought not to combine accepting the first (being resolved to eat no ice cream) with accepting the second (acting to eat this ice cream).
"You ought not to combine being resolved to eat no ice cream with acting to eat this ice cream"