union type support

[staabm]

properties are reported unused even though they are used via union type:

<?php

class A {
    public float $amount;
}

class B {
    public float $amount;
}

/** @param A|B $aOrB */
function doFoo($aOrB): void {
    echo $aOrB->amount;
}

function doFooBar(A|B $aOrB): void {
    echo $aOrB->amount;
}

reports

 ------ -------------------------------------------------------------------------------------------------------- 
  Line   test.php
 ------ --------------------------------------------------------------------------------------------------------
  3      Public property "A::$amount" is never used
         💡 Either reduce visibility or annotate it or its class with @api
  7      Public property "B::$amount" is never used
         💡 Either reduce visibility or annotate it or its class with @api

[staabm]

(working on a fix right now)