I have constructed a more elaborate test -

use strict;
use warnings;
use Data::Dumper;

# test 1
print for (1..10 or 'a'..'k');    # line 6
print "\n";

# test 2
my @range = 1..10 or 'a'..'k';    # line 10
print for (@range);
print "\n";

# test 3
my @r1 = 1..10;
my @r2 = 'a'..'k';
@range = @r1 or @r2;              # line 17
print for (@range);
print "\n";
[download]

And when I ran it, I got the following warnings and results -

Useless use of range (or flop) in void context at p92.pl line 10.
Useless use of private array in void context at p92.pl line 17.
Use of uninitialized value in range (or flip) at p92.pl line 6.
abcdefghijk
12345678910
12345678910
[download]

The warnings and results might give a clue to what is happenning with list/range and the for and or operators?