Refactor InitializerExprTypeResolver

[staabm]

After looking again at #4435 I think this minor simplification makes sense

[phpstan-bot]

This pull request has been marked as ready for review.

[VincentLanglet]

I was wondering if this simplification was interesting enough or if we should/could include the whole if ($leftTypesCount > 0 ...) given the fact the only changed line were

$resultType = $this->getTypeFromValue($leftTypeInner->getValue() | $rightTypeInner->getValue());
$resultType = $this->getTypeFromValue($leftTypeInner->getValue() & $rightTypeInner->getValue());
$resultType = $this->getTypeFromValue($leftTypeInner->getValue() ^ $rightTypeInner->getValue());

and could be resolve with a callback ; WDYT ?

[staabm]

and could be resolve with a callback ; WDYT ?

good idea - did it like that now.

my initial idea was to turn the pattern

		if ($leftType instanceof IntegerRangeType) {
			$leftTypes = $leftType->getFiniteTypes();
		} else {
			$leftTypes = $leftType->getConstantScalarTypes();
		}

into a TypeUtils method, so we can re-use it even outside of InitializerExprTypeResolver.
but for the InitializerExprTypeResolver-local refactoring it makes sense to go into your idea first.

thank you

[VincentLanglet]

The method might be easier to read with early return ?

if ($leftTypesCount === 0 || $rightTypesCount === 0) {
     return self::IS_UNKNOWN;
}
...
if ($generalize) {
     return self::IS_SCALAR_TYPE;
}
...
return TypeCombinator::union(...$resultTypes);
```

I also wonder if a Type|bool isn't enough (and avoid introducing two constant). True when it need to be generalized.
Another solution could be including the generalize call inside this method and returning `[$leftType, $rightType, $result]` but I'm not sure it should be preferred.

[staabm]

The method might be easier to read with early return ?

done.

I also wonder if a Type|bool isn't enough (and avoid introducing two constant).

I had it like that before I introduced constants. was not happy with the client-side code of this method as it was pretty unreadable.