if (isset($a->world)) { // shouldn't report any error

if ($a->hello !== null) { // should report notIdentical.alwaysTrue 

$this->richerScopeGetTypeHelper->getIdenticalResult($this->treatPhpDocTypesAsCertain ? $scope : $scope->doNotTreatPhpDocTypesAsCertain(), $node);

if (
			(
				$expr->left instanceof Node\Expr\PropertyFetch
				|| $expr->left instanceof Node\Expr\StaticPropertyFetch
			)
			&& $rightType->isNull()->yes()
			&& !$scope->hasPropertyNativeType($expr->left)
		) {
			return new TypeResult(new BooleanType(), []);
		}

class MyObject 
{
     /** @var string */
     public $foo; // This is initialized with NULL since no native type is used.
}