[perl #120973] [BUG] Cross product with a .map in the rhs yields an empty list in Rakudo

[Carl Mäsak]

# New Ticket Created by  "Carl Mäsak" 
# Please include the string:  [perl #120973]
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# <URL: https://rt.perl.org/Ticket/Display.html?id=120973 >


<clsn> r: say <a b>.map({$_}) X, <c d>.map({$_})
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«␤»
<clsn> What am I missing here?  Shouldn't that be the same as <a b> X, <c d>?
<masak> r: say (<a b>.map({$_}) X <c d>.map({$_}))
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«␤»
<masak> r: say (<a b> X <c d>)
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«a c a d b c b d␤»
<jnthn> r: say <a b>.map({$_})
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«a b␤»
<clsn> I was going to try to use stuff like that to check for
subsetness among param names, but this cropped up.
<clsn> r: say <a b>.perl; say <a b>.map({$_}).perl
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«("a",
"b")␤("a", "b").list␤»
* masak submits rakudobug
<masak> r: say (<a b>.map({$_}) X <c d>)
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«a c a d b c b d␤»
<masak> interesting. so it takes two maps.
<clsn> r: say (<a b> X <c d>.map({$_}))
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«␤»
<clsn> No, only the second one it looks like.
<masak> oh!
<masak> yes.
<masak> clsn++
<masak> r: say (<a b> X <c d>.map({$_})).perl
<camelia> rakudo-parrot 58307f, rakudo-jvm 58307f: OUTPUT«().list␤»