Phan\Language\UnionType::canCastToExpandedUnionType PHP Method

    public function canCastToExpandedUnionType(UnionType $target, CodeBase $code_base) : bool
    {
        $this_expanded = $this->asExpandedTypes($code_base);
        $target_expanded = $target->asExpandedTypes($code_base);
        return $this_expanded->canCastToUnionType($target_expanded);
    }

 /**
  * @param Node $node
  * A node to parse
  *
  * @return Context
  * A new or an unchanged context resulting from
  * parsing the node
  */
 public function visitProp(Node $node) : Context
 {
     $property_name = $node->children['prop'];
     // Things like $foo->$bar
     if (!is_string($property_name)) {
         return $this->context;
     }
     assert(is_string($property_name), "Property must be string in context {$this->context}");
     try {
         $class_list = (new ContextNode($this->code_base, $this->context, $node->children['expr']))->getClassList();
     } catch (CodeBaseException $exception) {
         // This really shouldn't happen since the code
         // parsed cleanly. This should fatal.
         // throw $exception;
         return $this->context;
     } catch (\Exception $exception) {
         // If we can't figure out what kind of a class
         // this is, don't worry about it
         return $this->context;
     }
     foreach ($class_list as $clazz) {
         // Check to see if this class has the property or
         // a setter
         if (!$clazz->hasPropertyWithName($this->code_base, $property_name)) {
             if (!$clazz->hasMethodWithName($this->code_base, '__set')) {
                 continue;
             }
         }
         try {
             $property = $clazz->getPropertyByNameInContext($this->code_base, $property_name, $this->context);
         } catch (IssueException $exception) {
             $exception->getIssueInstance()();
             return $this->context;
         }
         if (!$this->right_type->canCastToExpandedUnionType($property->getUnionType(), $this->code_base)) {
             Issue::emit(Issue::TypeMismatchProperty, $this->context->getFile(), $node->lineno ?? 0, (string) $this->right_type, "{$clazz->getFQSEN()}::{$property->getName()}", (string) $property->getUnionType());
             return $this->context;
         }
         // After having checked it, add this type to it
         $property->getUnionType()->addUnionType($this->right_type);
         return $this->context;
     }
     if (Config::get()->allow_missing_properties) {
         try {
             // Create the property
             (new ContextNode($this->code_base, $this->context, $node))->getOrCreateProperty($property_name);
         } catch (\Exception $exception) {
             // swallow it
         }
     } else {
         if (!empty($class_list)) {
             Issue::emit(Issue::UndeclaredProperty, $this->context->getFile(), $node->lineno ?? 0, $property_name);
         } else {
             // If we hit this part, we couldn't figure out
             // the class, so we ignore the issue
         }
     }
     return $this->context;
 }