Reproducible case for https://github.com/schwern/method-signatures/issues/41

Bar.pm

use strict;
use warnings;
package Bar;
use MyBase;

1;

Foo.pm

use strict;
use warnings;
package Foo;
use MyBase 'Bar';

1;

MyBase.pm

use strict;
use warnings;
package MyBase;

require Method::Signatures;

sub import {
    my ($class, $base) = (@_);
    Method::Signatures->import( { into => scalar caller } );
    return unless $base;

    my $file = $base;
    $file =~ s/::|'/\//g;
    $file .='.pm';
    require $file;
}

1;

script.pl

use lib '.';
use Foo;

1;