Why does IQueryable.All() return true on an empty collection?

Question

So I ran into a situation today where some production code was failing precisely because a method performed exactly as documented in MSDN. Shame on me for not reading the d

Answer 1

I think it makes sense. In logic, the complement of FOR ALL is NOT (THERE EXIST). FOR ALL is like All(). THERE EXIST is like Any().

So IQueryable.All() is equivalent to !IQueryable.Any(). If your IQueryable is empty, then both returns true based on MSDN doc.