Feature request

str_replace could be considered pure, when the by-ref parameter is not passed.

https://phpstan.org/r/6d607859-e782-47bf-8da3-a6ba95bae922
I would expect no error in this snippet.

should also be fixed in str_ireplace, preg_replace while at it - but I guess we will find a solution which is independent of concrete function signatures.

Did PHPStan help you today? Did it make you happy in any way?

finds bugs every day - you know that ;)