PHP执行因未知原因而停止

Execution of my PHP script halts if I have this piece of code in it with no error

return str_replace( 
    str_repeat($currentOsSeparator, 2),
    '//',
    str_replace(
        $separators,
        $currentOsSeparator,
        $path),
    1);

Now, the tricky part is that execution stops even if this code is after a return statement.

Is that supposed to be a function? Not sure what you're trying to do. The error returned for the above code on its own is

PHP Fatal error: Only variables can be passed by reference

You should read this: http://php.net/manual/en/function.return.php

If called from the global scope, then execution of the current script file is ended

But without seeing more of your code or more explanation it's hard to help.