>type ModA.pm
package ModA;
use Exporter qw( import );
@EXPORT = qw( foo );
sub foo { print __PACKAGE__, "\n" }
1;

>type ModB.pm
package ModB;
use Exporter qw( import );
@EXPORT = qw( foo );
sub foo { print __PACKAGE__, "\n" }
1;

>perl -we"use ModA; use ModB;"
Subroutine main::foo redefined at c:/Progs/perl5101/lib/Exporter.pm line 67.
 at -e line 1