Mistreating division by zero is a logical error as you say, not a runtime error. No one has made any claims in this thread about logical errors, other than my earlier statement that Elm does not preclude them. The things which have been referred to as runtime errors for decades are not present in Elm, that’s really the only point here. In order to make that guarantee, there’s a couple of potholes where logical errors may crop up, it’s a worthwhile trade to many people.