use strict;
use warnings;
use 5.010;

for my $num (1 .. 5) {

    say "start of for loop: $num";

    {say "in block: $num"};

    sub test {
        say "in function: $num";
    }

    test()
}

--output:--
start of for loop: 1
in block: 1
Use of uninitialized value $num in concatenation (.) or string at 3perl.pl line 11.
in function: 
start of for loop: 2
in block: 2
Use of uninitialized value $num in concatenation (.) or string at 3perl.pl line 11.
in function: 
..
..