Post-incrementing native integers across overflow boundary

[lucasbuchala]

Post-incrementing native integers across overflow boundary gives wrong answer. My expectation is that $x++ should evaluate to the same value of $x before the operation.

> say my int8 $x = 127; say $x++; say $x
127
-129
-128

> say my int16 $x = 32767; say $x++; say $x
32767
-32769
-32768

This is Rakudo version 2018.11 built on MoarVM version 2018.11

[lizmat]

Thanks for your report.

To my knowledge, this behaviour is intentional with regards to native integer variables. I'm therefore closing this issue. Please re-open if you disagree.

[lizmat]

This appears to be an optimizer issue:

$ perl6 -e 'my int8 $a = 127; say $a++'
-129

perl6 --optimize=0 -e 'my int8 $a = 127; say $a++'
127

[lizmat]

Simply removing the optimization in the static optimizer, breaks spectests.

OTOH, this problem has been around since at least Christmas 2015, so it looks like it's not a very common occurrence. So I don't need to see a need to add a blocker label just yet.