[New Rule] Multiple isset statements SHOULD be combined into one

[lenaorobei]

Rule

Multiple isset statements SHOULD be combined into one.

Reason

Just the code style question aimed to make the codebase consistent.

Bad example:

if (isset($a) && isset($b) && isset($c)) {
    // code goes here
}

Good example:

if (isset($a, $b, $c)) {
    // code goes here
}

Implementation

Check for multiple isset statements combined with && inside one condition.

[buskamuza]

As for me, it's OK to have both styles. There can be use cases with if (isset($a) && empty($b)), and in this case it looks more consistent with the bad example.
If many people vote that this sniff can improve readability of the code, let it be. Otherwise I would not restrict this.

[ravmenon]

For extensions, this should be only a low severity (style) warning as the first idiom is very common.

[lenaorobei]

No updated and votes here, so both styles are ok.
No need to enforce.