The hint that reports unused functions vars and class members ignores code in assertions.

Example:

class FooEnum
{
    const A = 0;
    const B = 1;
    const C = 2;
    private static $_valid = array(self::A,self::B,self::C);
    private $foo = self::A;
    public function setFoo($value)
    {
        // pre-condition
        assert('in_array($value, self::$_valid); // Invalid input type');
        // more code
        // post-condition
        assert('in_array($this->foo, self::$_valid); // Invalid output type');
    }
    public function getFoo()
    {
        // pre-condition
        assert('in_array($this->foo, self::$_valid); // Invalid output type');
        return $this->foo;
    }
}

For the above snippet NetBeans will report FooEnum::$_valid as unused. But it is not - and if it is removed (as NetBeans
suggests) all assertions will result in runtime-errors terminating the program.

While unlike Java, assertions are always embraced in quotes in PHP, they are real source code and should be interpreted
that way - just as they are in Java. If NetBeans supports the one it should also work with the other.

Personally I would prefer that NetBeans would be able to honor assertions. At least when it comes to single-quoted
strings in assertions like '$foo' - which is 1:1 standard PHP source-code. I understand that there are more complex
examples where people use variable substitution BUT these are a rarely seen, since it does not comply with common rules
for writing assertions (not in Java and also not in PHP). At least 95% of all assertions will use very basic
expressions. Typical assertions are: type-checking, checking that a value doesn't fall below zero, checking that a value
is not Null or a var has not been previously used.

As an alternative it would be nice to at least be able to persistently turn off this warning in NetBeans for just a
single class member, function or variable.

I suggest setting this issue to a low priority and keeping it on the "todo"-list for a future version.