permutations(30) and count-only

[AlexDaniel]

Code:

say +permutations(30)

Result (2016.07.1):

265252859812191058636308480000000

Result (HEAD(beaad7b)):

Cowardly refusing to permutate more than 20 elements, tried 30
in block <unit> at /tmp/78oLs8E9NR line 1

Change bisected: (2016-09-09) 8a66833

Output on all 6c releases: https://gist.github.com/0c7ecedcd136277d8692e36560670121

Basically, this part:

rakudo/src/core/Rakudo/Iterator.pm

Lines 2343 to 2347 in 005714b

	nqp::if(
	$n > nqp::if(nqp::iseq_i($?BITS,32),13,20), # must be HLL comparison
	(die "Cowardly refusing to permutate more than {
	$?BITS == 32 ?? 13 !! 20
	} elements, tried $n"),

is too early, and because of that it never gets to this:

rakudo/src/core/Rakudo/Iterator.pm

Lines 2433 to 2436 in 005714b

	method count-only {
	nqp::isge_i($!todo, 0) ?? nqp::p6box_i($!todo) !! 0
	}
	method bool-only { nqp::p6bool(nqp::isgt_i($!todo, 0)) }

Somewhat related: #1331

[taboege]

I'd question in general if the method should really fail because an argument is too big for an implementation detail to work. That's not tormenting the implementors enough.