[perl #124330] Generating Pascal's triangle with lazy list generator fails (integration/advent2012-day04.t)

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# New Ticket Created by  Christian Bartolomaeus 
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There is a spectest failure in integration/advent2012-day04.t (test 3, "Problem 
53", generating Pascal's triangle).

< bartolin_> m: sub pascal { [1], { [0, @^p Z+ @^p, 0] } ... * }; .say for 
pascal[^10];
<+camelia> rakudo-moar a24488: OUTPUT«1␤1␤1␤1␤1␤1␤1␤1␤1␤1␤»
< bartolin_> star-m: sub pascal { [1], { [0, @^p Z+ @^p, 0] } ... * }; .say for 
pascal[^10];
<+camelia> star-m 2015.03: OUTPUT«1␤1 1␤1 2 1␤1 3 3 1␤1 4 6 4 1␤1 5 10 10 5 1␤1 
6 15 20 15 6 1␤1 7 21 35 
                 35 21 7 1␤1 8 28 56 70 56 28 8 1␤1 9 36 84 126 126 84 36 9 1␤»
< bartolin_> ^^ that's from 
http://rosettacode.org/wiki/Pascal%27s_triangle#Perl_6 (and 
                   integration/advent2012-day04.t)
< bartolin_> I remember breaking it a month ago (by improperly flattening 
values within SEQUENCE). but it 
                   was fixed afterwards.
< bartolin_> seems to fail since 2015-04-10

There was a rewrite of the infix:<...> operator on 2014-05-09, probably causing 
the changed behaviour (cmp. 
https://github.com/rakudo/rakudo/commits/nom/src/core/operators.pm).