[Php70] Skip memoize item by key on IfIssetToCoalescingRector

[samsonasik]

Fixes rectorphp/rector#9784
Ref https://getrector.com/demo/17f33148-a662-4998-b212-d8a5ed25b305

The transformed code become hard to read can possibly cause changed behaviour due to no parentheses on complex use.

-        if (isset($this->items[$key])) {
-            return $this->items[$key];
-        }
-
-        return $this->items[$key] = 'default';
+        return $this->items[$key] ?? $this->items[$key] = 'default';

so I think it should be skipped.

[samsonasik]

@TomasVotruba ready 👍

[TomasVotruba]

Indeed, I don't get what it does from briefly looking at it.

Thanks, nice improvement 👍