in a
got wrong value foo
 at foo.pl line 17
        main::b('foo') called at foo.pl line 13
        main::a() called at foo.pl line 9
in c
dying because of bar!
 at foo.pl line 23
        main::c('bar') called at foo.pl line 18
        main::b('foo') called at foo.pl line 13
        main::a() called at foo.pl line 9