Phan\Language\Type::isSelfTypeString PHP Method

    public static function isSelfTypeString(string $type_string) : bool
    {
        return in_array(strtolower($type_string), ['self', '$this', 'parent', '\\self', '\\$this', '\\parent']);
    }

 /**
  * @param CodeBase $code_base
  * The global code base
  *
  * @param FunctionInterface $method
  * The method we're analyzing arguments for
  *
  * @param Node $node
  * The node holding the method call we're looking at
  *
  * @param Context $context
  * The context in which we see the call
  *
  * @return null
  *
  * @see \Phan\Deprecated\Pass2::arglist_type_check
  * Formerly `function arglist_type_check`
  */
 private static function analyzeParameterList(CodeBase $code_base, FunctionInterface $method, Node $node, Context $context)
 {
     foreach ($node->children ?? [] as $i => $argument) {
         // Get the parameter associated with this argument
         $parameter = $method->getParameterList()[$i] ?? null;
         // This issue should be caught elsewhere
         if (!$parameter) {
             continue;
         }
         // If this is a pass-by-reference parameter, make sure
         // we're passing an allowable argument
         if ($parameter->isPassByReference()) {
             if (!$argument instanceof \ast\Node || $argument->kind != \ast\AST_VAR && $argument->kind != \ast\AST_DIM && $argument->kind != \ast\AST_PROP && $argument->kind != \ast\AST_STATIC_PROP) {
                 Issue::maybeEmit($code_base, $context, Issue::TypeNonVarPassByRef, $node->lineno ?? 0, $i + 1, (string) $method->getFQSEN());
             } else {
                 $variable_name = (new ContextNode($code_base, $context, $argument))->getVariableName();
                 if (Type::isSelfTypeString($variable_name) && !$context->isInClassScope() && $argument->kind == \ast\AST_STATIC_PROP && $argument->kind == \ast\AST_PROP) {
                     Issue::maybeEmit($code_base, $context, Issue::ContextNotObject, $node->lineno ?? 0, "{$variable_name}");
                 }
             }
         }
         // Get the type of the argument. We'll check it against
         // the parameter in a moment
         $argument_type = UnionType::fromNode($context, $code_base, $argument);
         // Expand it to include all parent types up the chain
         $argument_type_expanded = $argument_type->asExpandedTypes($code_base);
         // Check the method to see if it has the correct
         // parameter types. If not, keep hunting through
         // alternates of the method until we find one that
         // takes the correct types
         $alternate_parameter = null;
         $alternate_found = false;
         foreach ($method->alternateGenerator($code_base) as $alternate_id => $alternate_method) {
             if (empty($alternate_method->getParameterList()[$i])) {
                 continue;
             }
             // Get the parameter associated with this argument
             $alternate_parameter = $alternate_method->getParameterList()[$i] ?? null;
             // Expand the types to find all parents and traits
             $alternate_parameter_type_expanded = $alternate_parameter->getUnionType()->asExpandedTypes($code_base);
             // See if the argument can be cast to the
             // parameter
             if ($argument_type_expanded->canCastToUnionType($alternate_parameter_type_expanded)) {
                 $alternate_found = true;
                 break;
             }
         }
         if (!$alternate_found) {
             $parameter_name = $alternate_parameter ? $alternate_parameter->getName() : 'unknown';
             $parameter_type = $alternate_parameter ? $alternate_parameter->getUnionType() : 'unknown';
             if ($method->isInternal()) {
                 Issue::maybeEmit($code_base, $context, Issue::TypeMismatchArgumentInternal, $node->lineno ?? 0, $i + 1, $parameter_name, $argument_type_expanded, (string) $method->getFQSEN(), (string) $parameter_type);
             } else {
                 Issue::maybeEmit($code_base, $context, Issue::TypeMismatchArgument, $node->lineno ?? 0, $i + 1, $parameter_name, $argument_type_expanded, (string) $method->getFQSEN(), (string) $parameter_type, $method->getFileRef()->getFile(), $method->getFileRef()->getLineNumberStart());
             }
         }
     }
 }