[perl #126060] [GLR] the 'for' modifier doesn't respect itemization on single arg

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# New Ticket Created by  Larry Wall 
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perl6-m -e 'for $[1,2,3] { .say }; .say for $[1,2,3];'
[1 2 3]
1
2
3

This showed up in the following rosettacode entry:

.say for identity-matrix(5);
sub identity-matrix($n) {
    [1, |(0 xx $n-1)].item, *.rotate(-1).item ... *[*-1] == 1
}

which produces

[1 0 0 0 0]
[0 1 0 0 0]
[0 0 1 0 0]
[0 0 0 1 0]
0
0
0
0
1