[perl #79908] Stop sub inlining from breaking closures
When a closure closes over a variable, it references the variable
itself, as opposed to taking a snapshot of its value.
This was broken by the constant optimisation added for
constant.pm’s sake:
{
my $x;
sub () { $x }; # takes a snapshot of the current value of $x
}
constant.pm no longer uses that mechanism, except on older perls, so
we can remove this hack, causing code like this this to start work-
ing again:
BEGIN{
my $x = 5;
*foo = sub(){$x};
$x = 6
}
print foo; # now prints 6, not 5