there is a "workaround": either move $mod1 into the begin-block:

package SearchMachine;
use warnings;
use strict;
BEGIN {
  my $mod1 = "/path/MySearch.pm";
  require $mod1;
}
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or move the require out of the begin block:

package SearchMachine;
use warnings;
use strict;
my $mod1 = "/path/MySearch.pm";
require $mod1;
[download]