[TypeCoverage] Add EmptyOnNullableObjectToInstanceOfRector

[TomasVotruba]

No description provided.

[someniatko]

Hi, I find this one a bit weird, however some may find it appropriate. Is there a rule to change empty($nullableObj) to $nullableObj === null instead?

[TomasVotruba]

Hi, that would not make sense, as comparison is weak.

[someniatko]

I might be missing something obvious here:

?AnotherObject type has exactly two atomic possibilities: either AnotherObject, or null, there cannot be a third variant. Passing an instanceof check guarantees it is AnotherObject, and negating it guarantees it is null, thus ! $x instanceof AnotherObject is equivalent to $x === null.