Incorrect behavior of TernaryFalseExpressionToIfRector

[gehrisandro]

Bug Report

Subject	Details
Rector version	last dev-main
Installed as	composer dependency

Minimal PHP Code Causing Issue

See https://getrector.com/demo/66f82535-275a-4804-bdbe-cc6b10f9cabc

<?php

final class DemoFile
{
    public function run(bool $param): void
    {
        $param ? $this->a() : $this->b();
    }

    public function a(): void
    {

    }

    public function b(): void
    {

    }
}

Responsible rules

• TernaryFalseExpressionToIfRector

Expected Behavior

Rector should not modify the code. This issue is not related to a specific rector version. Instead it depends on the phpstan version used.
I was able to trace this down to a change introduces in phpstan version 1.10.49. And specifically this PR: phpstan/phpstan-src#2778

The problem is basically that rector has changed the return type from a VoidType to NullType which is an instance of ConstantType which then leads to this unexpected refactor.

But I think this is a problem of the TernaryFalseExpressionToIfRector in general. Because if method b has null as return type instead of void it happens regardless of the phpstan version used, which is wrong too: https://getrector.com/demo/5d99559b-c987-4e15-9ae8-c44fd2d33023

In my opinion, the rector should never perform a refactor if the else of the Ternary operator is a function call.