Bug report

PHPStan 1.6.8

If I pass an array to shuffle(), I get an array again, as one could expect. (And I didn't find any presence that shuffle treated in a special way in the PHPStan's source code, searched for shuffle across the project.)
https://phpstan.org/r/fcc029c7-a91e-4e98-8656-c21ed32e7480

If I pass an array to parse_str(), its type resets to mixed for some reason.
If I pass a float to similar_text(), its type resets to mixed too.
https://phpstan.org/r/83cf5048-7004-4588-8a52-451f75b215be

I think it can be safely assumed that standard PHP functions don't change by-ref arguments' type and it always will be the same as specified in a signature.

Code snippet that reproduces the problem

https://phpstan.org/r/83cf5048-7004-4588-8a52-451f75b215be

Expected output

By-ref arguments' type passed to standard functions shouldn't be erased to mixed.