Re^7: Is this DBM::Deep behavior, or something with tie/bless? (ref)

Yes, I have an open bug against Data::Diver for issuing warnings about pseudo-hashes due to this.

You are right about the other warnings as well. Unfortunately, your alternative has other problems:

my $foo;
if(  eval { \@$foo }  ) {
    print $foo, $/;
}
__END__
ARRAY(0x34d10)
[download]

In the case of CODE ref testing, there is a different problem:

my $foo= "not_a_code_reference";
print "oops!\n"
    if  eval { \&$foo };
[download]

Of course, in some situations, one could consider the latter a feature. But mostly I think it would be unwanted.

It is very sad that Perl still doesn't provide decent tools for determine the data type(s) of a reference. It is no wonder nobody gets this right.