The issue https://github.com/perl6/specs/issues/47 has been closed by the end of last year. Now there is a method "narrow" which can be used in this case (I'll add a test for this):
$ perl6 -e 'say ~( 64, {($_/2).narrow} ...^ Rat)' 64 32 16 8 4 2 1 The sequence operator doesn't auto-coerce Rats to Ints (same behaviour as back in 2010; there also is a passing test for this behaviour in S03-sequence/basic.t since 2010-10-21). $ perl6 -e 'say ~(64,32,16 ...^ Rat)' 64 32 16 So, was a consensus reached and this ticket can be closed?