From @LLFourn

my @​data = 1,{},@​data,"YEWHAT??";
say @​data.perl;

# (\Array_140251854808256 = [1 Array_140251854808256 YEWHAT??])

It's putting the {} before it that makes the check stop working

p 'my @​data = 1,@​data,"YEWHAT??";say @​data'
===SORRY!=== Error while compiling -e
Cannot use variable @​data in declaration to initialize itself
at -e​:1

I had a ',' where a ';' should have been and it slurped up the next line
where I used @​data, and put it into itself. Took me forever to figure it
out!

From @zoffixznet

Still present in today's rakudo de5d9e​:

<Zoffix> m​: my @​data = @​data;
<camelia> rakudo-moar de5d9e​: OUTPUT«===SORRY!=== Error while compiling <tmp>␤Cannot use variable @​data in declaration to initialize itself␤at <tmp>​:1␤------> my @​data = @​⏏data;␤ expecting any of​:␤ term␤»
<Zoffix> m​: my @​data = {}, @​data;
<camelia> rakudo-moar de5d9e​: ( no output )

@coke - Status changed from 'new' to 'open'