conflict-methods-trait-addition.pl

package T;
use Moose::Role;

sub a { 'x' }
sub b { 'y' }
sub c { shift->i }

package U;
use Moose::Role;

sub c { 'q' }
sub d { 'r' }

package TU;
use Moose::Role;

with 'T', 'U';

package My::Class;
use Moose;
with 'TU';

sub i { 'self->i' };
# sub c { 'my c' }; # Adding c cease the error shown in [Note 1]

package main;
use Modern::Perl;
use My::Class;

my $c = My::Class->new();
say $c->a;
say $c->b;
say $c->c;
say $c->d;
say $c->i;

__END__

Following [1], we are testing method conflict marker, with two traits adition:
T + U, both having message c() implemented.

Moose have so implemented the traits aditions the same way the paper describes,
with the resolution to mark the conflict method "c" in T + U.
And generates the following error:

[Note 1]
`` Due to a method name conflict in roles 'T' and 'U', the method 'c' must be
 implemented or excluded by 'My::Class' at 
/home/itaipu/perl5/lib/perl5/x86_64-linux-gnu-thread-multi/Moose/Exporter.pm
line 419 ''


Bibliography:

[1] A. P. Black, N. Schärli, and S. Ducasse, “Applying traits to the smalltalk
collection classes,” in ACM SIGPLAN Notices, 2003, vol. 38, pp. 47–64.