[perl #127951] Probably removing a p6bool where it shouldn't

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# New Ticket Created by  Elizabeth Mattijsen 
# Please include the string:  [perl #127951]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=127951 >


[17:01:04]  <lizmat>    m: my $a = 42; say $a =:= $a; say $a.WHAT =:= $a.WHAT; 
say $a == $a; say $a =:= $a || $a.WHAT =:= $a.WHAT   # where does the 1 come 
from ???
[17:01:05]  <camelia>   rakudo-moar fe2be6: OUTPUT«True␤True␤True␤1␤»
[17:03:18]  <jnthn>     m: my $a = 42; say $a =:= $a || $a.WHAT =:= $a.WHAT
[17:03:18]  <camelia>   rakudo-moar fe2be6: OUTPUT«1␤»
[17:03:29]  <jnthn>     m: my $a = 42; say ($a =:= $a) || ($a.WHAT =:= $a.WHAT)
[17:03:29]  <camelia>   rakudo-moar fe2be6: OUTPUT«1␤»
[17:03:35]  <jnthn>     m: my $a = 42; say 0 || ($a.WHAT =:= $a.WHAT)
[17:03:35]  <camelia>   rakudo-moar fe2be6: OUTPUT«True␤»
[17:03:46]  <jnthn>     m: my $a = 42; say ($a =:= $a) || (say 'huh')
[17:03:46]  <camelia>   rakudo-moar fe2be6: OUTPUT«1␤»
[17:03:57]  <jnthn>     m: my $a = 42; say $a =:= $a
[17:03:57]  <camelia>   rakudo-moar fe2be6: OUTPUT«True␤»
[17:04:01]  <jnthn>     m: my $a = 42; say ?($a =:= $a)
[17:04:02]  <camelia>   rakudo-moar fe2be6: OUTPUT«True␤»
[17:04:19]  <jnthn>     m: my $a = 42; say do unless $a =:= $a { 'x' }
[17:04:19]  <camelia>   rakudo-moar fe2be6: OUTPUT«()␤»
[17:04:25]  <jnthn>     lizmat: I...have no idea!
[17:04:45]  <jnthn>     Does it show up with --optimize=off?
[17:04:49]  <lizmat>    do you agree this is spooky?
[17:04:54]  <jnthn>     Yes :)
[17:05:26]  <jnthn>     m: my $a = 42; say (($a =:= $a) or ($a.WHAT =:= 
$a.WHAT))
[17:05:26]  <camelia>   rakudo-moar fe2be6: OUTPUT«1␤»
[17:05:42]  <jnthn>     m: my $a = 42; say (($a =:= $a) // ($a.WHAT =:= 
$a.WHAT))
[17:05:42]  <camelia>   rakudo-moar fe2be6: OUTPUT«True␤»
[17:05:45]  <lizmat>    indeed, this shows up from optimize=2
[17:06:12]  <jnthn>     m: use nqp; my $a = 42; say nqp::unless($a =:= $a, 
$a.WHAT =:= $a.WHAT)
[17:06:12]  <camelia>   rakudo-moar fe2be6: OUTPUT«1␤»
[17:06:15]  <lizmat>    $ perl6 --optimize=1 -e 'my $a = 42; say $a =:= $a || 
$a.WHAT =:= $a.WHAT'
[17:06:15]  <lizmat>    True
[17:06:23]  <lizmat>    $ perl6 --optimize=2 -e 'my $a = 42; say $a =:= $a || 
$a.WHAT =:= $a.WHAT'
[17:06:23]  <lizmat>    1
[17:06:32]  <jnthn>     Well, that isolates it a good bit, then :)
[17:06:44]  <lizmat>    rakudobug it ?
[17:06:48]  <jnthn>     yeah
[17:06:52]  <lizmat>    ok, will do
[17:07:00]  <jnthn>     I wonder if it's elimiating a nqp::p6bool thinking it's 
not needed
[17:08:50]  <lizmat>    around line 1250 in Optimizer seems to be applicable
[17:08:59]  <lizmat>    way over my head, though...