Cannot call method on ternary with common parent class

[bwoebi]

Having a conditional type like (IsClient is true ? Child1 : Child2) and calling a method on it will fail with InvalidMethodCall, though all methods on the intersection Child1&Child2 should be trivially callable.

https://psalm.dev/r/1629e589b7

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/1629e589b7

<?php

class Old {
    public function x(): void {}
}
class Child1 extends Old {}
class Child2 extends Old {}

/**
 * @template IsClient of bool
 */
class A {
    /**
     * @psalm-param (IsClient is true ? Child1 : Child2) $var
     */
    public function test(Old $var): void {
        $var->x();
    }
}

Psalm output (using commit a75d26a):

ERROR: InvalidMethodCall - 17:15 - Cannot call method on (IsClient is true ? Child1 : Child2) variable $var