As I keep telling people, dont trust the docs; they will carefully craft a technically correct but worthless at explanation why your code will fail
countUntil and isCallable are ones ive interacted with NEITHER have a clear explanation why its fundamentally bad
>Counts elements in the given forward range until the given predicate is true for one of the given needles.
Why that sounds like indexOf, herp derp, every user better go learn the hardway why it isnt named that. Its SO fun to have an off by one error when a user does some unicode while all your test cases in ascii work perfectly; every user should get that learning experience.
The docs rants useless describing the horrible compromises inside the function; not clear descriptions of when it will break which would actually help users
Bolded #WONTFIX: countUntil does not provide indexs, and never can
#WONTFIX: isCallable doesnt untangle templated functions
#WONTFIX: delegates dont mix well with loops
etc etc etc
Being technically correct while pretending it works is worthless.