I'm usually don't even want to supress the error (this usually means the input data is wrong and I need to deal with it)

If it's undefs in a Perl data structure that you seek...

sub seek_undef {
    my ($ref,$path) = (@_,"");
    if (ref $ref eq 'HASH')
        { seek_undef($ref->{$_}, $path."{$_}") for keys %$ref }
    elsif (ref $ref eq 'ARRAY')
        { seek_undef($ref->[$_], $path."[$_]") for 0..$#$ref }
    else { defined $ref or warn "undef at $path\n" }
}

seek_undef( {
    foo => { quz=>{ abc=>"def", ghi=>undef } },
    bar => { baz=>[ "jkl", undef, { ooo=>undef } ],
        blah=>undef },  uuu => undef,
} );

__END__

undef at {foo}{quz}{ghi}
undef at {bar}{baz}[1]
undef at {bar}{baz}[2]{ooo}
undef at {bar}{blah}
undef at {uuu}
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