"By design, the All operator returns true for an empty sequence."

You cunt face!

Lol, had something similar a few months ago the fucking ldap lib login function in php returns true if you provide an empty password wtf.

Just check before and wrap it into an extension method... i did the same with sum and average as they throw Exceptions on empty enumerables.

Yeah. This has caught me out a few times and it makes me rage constantly.

I genuinely don’t understand why they made this decision, it’s so stupid.

I guess at a stretch you can say that yes, the predicate does apply to all elements of the set because the set is empty, but it’s so fucking counterintuitive.

@Brolls Wikipedia says that the universal quantification of the empty set is by convention always true.

Never seen any implementation that would return false. If a predicate is true for all elements in a set, it should not magically become false when you remove 1, 2, .., all elements.