Description:
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Built-in functions where a parameter is defined with ZEND_SEND_PREFER_REF raises a Strict Standards warning if an expression is passed as the argument.

The PREFER part signals the preference of passing by reference, but if the argument is not a variable, it should behave as if the parameter was defined with ZEND_SEND_BY_VAL and keep quiet, just as for regular ZEND_SEND_BY_VAL parameters.

Test script:
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<?php

error_reporting(32767);

current($arr = array(0 => "a")); /* Strict Standards: ... */ 
current(array(0 => "a"));
current($arr);

?>

Actual result:
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Strict Standards: Only variables should be passed by reference in filename on line 5