Howdy!

CAVEAT: this is off the cuff and untested...

Consider:

my $foo = bless {}, 'package::name';
$foo->can('function');
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That is, bless something into the namespace you are checking and use that object to try 'can' against.

UPDATE:

Reading Re: Re (tilly) 1: Strict, strings and subroutines by merlyn, I see where this needs to not search ISA, leading (by way of cribbing)

do { local @ISA;
    my $foo = bless {}, 'package::name';
    $foo->can('function');
};
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yours,
Michael