* LVALUES don't work
* Math::BigRat exhibit a similiar problem:
  # perl -Ilib example/psize "Math::BigRat->new(2)" "c => 1"
  Size report v0.05 for 'Math::BigRat->new(2)' => '2' (Math::BigRat):
    Hash (Math::BigRat) 517 bytes (overhead: unknown)
      '_d' => Hash (Math::BigInt) 299 bytes (overhead: 185 bytes, 61.87%)
        'value' => Array 72 bytes (overhead: 56 bytes, 77.78%)
          Scalar 16 bytes
        '_f' => Scalar 16 bytes
        'sign' => Scalar 26 bytes
      '_n' => Hash (Math::BigInt) 299 bytes (overhead: 185 bytes, 61.87%)
        'value' => Array 72 bytes (overhead: 56 bytes, 77.78%)
          Scalar 16 bytes
        '_f' => Scalar 16 bytes
        'sign' => Scalar 26 bytes
      'sign' => Scalar 26 bytes
  Total: 517 bytes

* The same for the summary, referencing the same data twice seems to count it
  twice. However, the summery also has the problem to include all contained
  objects in the count, too.