Within your Moo based module, try this:

package Foo;

use Moo;
use Data::Dumper;

warn Dumper [sort keys %INC];



1;
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On my system with Perl 5.32 I get the following output:

$VAR1 = [
          'Carp.pm',
          'Config.pm',
          'Data/Dumper.pm',
          'Exporter.pm',
          'Foo.pm',
          'List/Util.pm',
          'Moo.pm',
          'Moo/Object.pm',
          'Moo/_Utils.pm',
          'Moo/sification.pm',
          'Scalar/Util.pm',
          'Sub/Util.pm',
          'XSLoader.pm',
          'bytes.pm',
          'constant.pm',
          'mro.pm',
          'overloading.pm',
          'strict.pm',
          'warnings.pm',
          'warnings/register.pm'
        ];
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So you can see that the utf8 pragma isn't enabled by default by Moo.

Can you provide a self-contained code snippet that demonstrates the namespace::clean issue? Also within the namespace::clean documentation, it does mention that you can pass an -except => [qw(foo bar)]; list of subs not to clean. Doing so may improve your experience.

Thank you very much for "warn Dumper sort keys %INC" - this is brilliant.

The problem with namespace:

use utf8;
use feature qw(signatures);
no warnings qw(experimental::signatures);

use Moo;
use namespace::clean;

sub BUILD($self) {
    $self->_set_count(1);
}
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An error: "The signatures feature is experimental ..."

Should I place no warnings after namespace::clean or there are other solutions? Maybe with namespace::clean -except?

The "problem" with Moo is that it re-enables all warnings that you previously disabled.

So a solution is to disable warnings after the use Moo; line:

use utf8;
use feature qw(signatures);

use Moo;
no warnings qw(experimental::signatures);
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If you're source code is encoded using UTF-8, add use utf8;.

If you're source code is encoded using ASCII, don't use use utf8;.