> The whole thing is a question of trust. Do you trust clients enough to give them the syntactic sugar of Array#sum even if their arrays may not all be strictly

> The whole thing is a question of trust. Do you trust clients enough to give them the syntactic sugar of Array#sum even if their arrays may not all be strictly summable? I agree that Ruby should embrace Freedom, but that does not mean that all choices programers make freely are good ones. This is not about whether programmers accidentally call #sum on arrays that cannot be summed. It is about whether, when I look at the methods implemented by Array, it describes what arrays do or what arrays sometimes do or may do once in a while. I actually think that Array#sum is the least objectionable in a single project where summing the elements may be common, maybe objectionable in ActiveSupport where every Rails project gets it whether they sum arrays or not, and absolutely wrong in Ruby's core libraries where every Ruby programmer will get it. Free choices should be scrutinized most carefully when they has the broadest impact.