I found another strange failure which dies the same way. The error happens in S32-list/combinations.t and can be golfed down to this:
$ ./perl6-j -e 'say (1).combinations(0..1); say ().combinations' (() (1)) Expected a native int argument for '$a' Like my original report this happens while using 'combinations' (this time as a method). Even if this one blows up in postfix:<++> I believe there is the same bug surfacing. Therefore I use this ticket to report the new error. I didn't bisect yet, but 78ba3df7e1 was still good and bc722abe2c was already bad. Note, that there is an NQP bump in between. $ perl6-j --ll-exception -e 'say (1).combinations(0..1); say ().combinations' (() (1)) Expected a native int argument for '$a' in postfix:<++> (gen/jvm/CORE.setting:9361) in postfix:<++> (gen/jvm/CORE.setting:2268) in pull-one (gen/jvm/CORE.setting:14468) in first (gen/jvm/CORE.setting:5229) in first (gen/jvm/CORE.setting:5228) in call_with_capture (gen/jvm/Metamodel.nqp:3854) in (gen/jvm/CORE.setting:698) in (gen/jvm/CORE.setting:14715) in first (gen/jvm/CORE.setting:14702) in combinations (gen/jvm/CORE.setting:16223) in combinations (gen/jvm/CORE.setting:16218) in <unit> (-e:1) in <unit-outer> (-e:1) in eval (gen/jvm/stage2/NQPHLL.nqp:1198) in (gen/jvm/stage2/NQPHLL.nqp:1288) in command_eval (gen/jvm/stage2/NQPHLL.nqp:1285) in command_eval (src/Perl6/Compiler.nqp:27) in command_line (gen/jvm/stage2/NQPHLL.nqp:1269) in MAIN (gen/jvm/main.nqp:37) in <mainline> (gen/jvm/main.nqp:33) in (gen/jvm/main.nqp)
