1.2.716. Modified Typed Parameter

Reports modified parameters, which have a non-scalar typehint. Such variables should not be changed within the body of the method. Unlike typed properties, which always hold the expected type, typed parameters are only guaranteed type at the beginning of the method block.

This problem doesn’t apply to scalar types : by default, PHP pass scalar parameters by value, not by reference. Class types are always passed by reference.

This problem is similar to Don’t Unset Properties : the static specification of the property may be unset, leading to confusing ‘undefined property’, while the class hold the property definition.

<?php

class x {

    function foo(Y $y) {
        // $y is type Y

        // A cast version of $y is stored into $yAsString. $y is untouched.
        $yAsString = (string) $y;

        // $y is of type 'int', now.
        $y = 1;

        // Some more code

        // display the string version.
        echo $yAsString;
        // so, Y $y is now raising an error
        echo $y->name;
    }
}

?>

1.2.716.1. Suggestions

• Use different variable names when converting a parameter to a different type.

• Only use methods and properties calls on a typed parameter.

1.2.716.2. Specs

Short name	Functions/ModifyTypedParameter
Rulesets	All, Analyze, Class Review
Exakat since	2.1.9
PHP Version	All
Severity	Minor
Time To Fix	Quick (30 mins)
Precision	Very high
Features	typehint, parameter
Available in	Entreprise Edition, Exakat Cloud