This works consistently now: $ perl6-m -e '.say for combinations -9999999999999999999, 2' ()
$ perl6-m -e '.say for combinations -999999999999999999, 2' () Calling combinations with a negative $k gives an empty list: $ perl6-m -e 'say combinations 4, -2' () I added tests for this behaviour to S32-list/combinations.t with commit https://github.com/perl6/roast/commit/132d97ffc9 I'm closing this ticket as 'resolved'.
