Hurray, finally I solved it.
Stupid, as always in such cases.

Take a look at my attribute's code:

has 'myattr' => ( 
        is      =>  'ro',
        isa     =>  'Int',
        lazy       => 1,
        default => \&_build_myattr,
        # build      => '_build_myattr',
    );

[download]

Simply exchanging the comment between "default" and "build" does not work and gives the mentioned error.
I also had to make a builder out of build. I had to debug deep into Moose until I found this typo

Thank You for Your patience.

And it came to pass that in time the Great God Om spake unto Brutha, the Chosen One: "Psst!"
(Terry Pratchett, Small Gods)

In reply to Re: Moose: apply Role at Runtime (build vs. default) by Brutha
in thread Moose: apply Role at Runtime (build vs. default) [solved] by Brutha

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