$suffixProvider is of type object<BenTools\Hostname...uffixProviderInterface>, but the property $suffixProvider was declared to be of type object<BenTools\Hostname...r\PublicSuffixProvider>. Are you sure that you always receive this specific sub-class here, or does it make sense to add an instanceof check?
Our type inference engine has found a suspicous assignment of a value to a property.
This check raises an issue when a value that can be of a given class or a super-class
is assigned to a property that is type hinted more strictly.
Either this assignment is in error or an instanceof check should be added for that assignment.
The return type of return $suffixes; (array) is incompatible with the return type declared by the interface BenTools\HostnameExtract...rInterface::getSuffixes of type BenTools\HostnameExtractor\SuffixProvider\iterable.
If you return a value from a function or method, it should be a sub-type of the
type that is given by the parent type f.e. an interface, or abstract method.
This is more formally defined by the
Lizkov substitution principle,
and guarantees that classes that depend on the parent type can use any instance
of a child type interchangably. This principle also belongs to the
SOLID principles
for object oriented design.
Our function my_function expects a Post object, and outputs the author
of the post. The base class Post returns a simple string and outputting a
simple string will work just fine. However, the child class BlogPost which
is a sub-type of Post instead decided to return an object, and is
therefore violating the SOLID principles. If a BlogPost were passed to
my_function, PHP would not complain, but ultimately fail when executing the
strtoupper call in its body.
Our type inference engine has found a suspicous assignment of a value to a property. This check raises an issue when a value that can be of a given class or a super-class is assigned to a property that is type hinted more strictly.
Either this assignment is in error or an instanceof check should be added for that assignment.