Description:
------------
In the documentation for ReflectionParameter::getDeclaringFunction():
http://www.php.net/manual/en/class.reflectionparameter.php
http://www.php.net/manual/en/reflectionparameter.getdeclaringfunction.php

The function is declared as:
public ReflectionFunction getDeclaringFunction ( void )

It should read as:
public ReflectionFunctionAbstract getDeclaringFunction ( void )

When calling getDeclaringFunction() on a method parameter reflection, we get a 
ReflectionMethod object, which extends ReflectionFunctionAbstract, not 
ReflectionFunction.

Test script:
---------------
$method = new ReflectionMethod('Locale', 'getRegion');
foreach ($method->getParameters() as $parameter) {
    $function = $parameter->getDeclaringFunction();
    var_export($function instanceof ReflectionFunction); // false
    var_export($function instanceof ReflectionFunctionAbstract); // true
}