You can use can to get the coderef of the method then Data::Dumper (and $Data::Dumper::Deparse) to dump the coderef. This should give you enough to determine where and how the method get defined.

#!/usr/bin/env perl

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

my $yada=Yada->new();
my $ref=$yada->can('yada');
$Data::Dumper::Deparse=1;
warn Data::Dumper->Dump([\$ref],[qw(*ref)]),' ';

package Yada;

use strict;
use warnings;

sub new {
    my ($class,@args)=@_;

    return bless {},$class;
     };

sub yada {
    my $self=shift;
    warn Data::Dumper->Dump([\$self],[qw(*self)]),' ';
     };
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which when run returns

c:\Users\Clueless>perl can.pl
$ref = \sub {
             package Yada;
             use warnings;
             use strict;
             my $self = shift();
             warn 'Data::Dumper'->Dump([\$self], ['*self']), ' ';
         };
  at can.pl line 10.
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