Hello.

I was playing with '/(?{ ... })/' and have found different 'my' behaviour inside eval-block, in 5.18 vs 5.14.
In the code below, I am playing with the task: "To find 2 numbers (from 0 to 2), which can not be the same, their sum is equal to 2, and the second one is bigger than first one".

    use warnings;
    use strict;
    $\ = $/;
    my $A = 2;
    
    my $_0to2 = join '', 0 .. 2;
    $_ = join '=', ( $_0to2 ) x 2;
    
    print "\$_:[$_]";
    
    print /^
        \d*(\d)\d* = \d*(\d)\d*
            (?(?{ my %h; map $h{ $_ } ++, $1, $2; 2 == keys %h }) | (*
+FAIL) )
            (?(?{ $1 < $2 }) | (*FAIL) )
            (?(?{ my $sum = $1 + $2; $sum == $A }) | (*FAIL) )
        $/x ?
            "MATCHED: \$1:[$1], \$2:[$2]"
        :
            "NOT_MATCHED"
        ;
[download]

Here I used conditionals "(?(condition)yes-pattern|no-pattern)" (perlre).

5.14.4 OUTPUT:

$_:[012=012]
NOT_MATCHED
[download]

5.18.2 OUTPUT:

$_:[012=012]
MATCHED: $1:[0], $2:[2]
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I haven't understand where is the different behaviour, because I haven't received any warnings by 'use warnings;'.
I found the difference when inserted 'print 0 + keys %h;' inside eval-block with hash (code line below). It printed many '3' (5.14) vs not more than '2' (5.18). It seems that 'my %h;' haven't refreshed a hash. I guess it was known behaviour. When have it changed?
Upd.:

(?(?{ my %h; map $h{ $_ } ++, $1, $2; print 0 + keys %h; 2 == keys %h 
+}) | (*FAIL) )
[download]

Upd.2:Have swapped versions to correct