Null not work correctly

[lasotaartur]

I have problem with comparing null value

This works

$factory = new SimpleFactory();
$matcher = $factory->createMatcher();
$json1 = '{"proformaInvoiceLink":null}';
$json2 = '{"proformaInvoiceLink":null}';
 $match = $matcher->match($json1, $json2);

But this not works

$factory = new SimpleFactory();
$matcher = $factory->createMatcher();
$json1 = '{"proformaInvoiceLink":null, "test":"test"}';
$json2 = '{"proformaInvoiceLink":null, "test":"@string@"}';
 $match = $matcher->match($json1, $json2);

When I use @null@ it works

$factory = new SimpleFactory();
$matcher = $factory->createMatcher();
$json1 = '{"proformaInvoiceLink":null, "test":"test"}';
$json2 = '{"proformaInvoiceLink":@null@, "test":"@string@"}';
 $match = $matcher->match($json1, $json2);

I think that second example should works too.

[lasotaartur]

Can someone help me?