GraphQL\Language\Parser::parseTypeExtensionDefinition PHP Method

    function parseTypeExtensionDefinition()
    {
        $start = $this->lexer->token;
        $this->expectKeyword('extend');
        $definition = $this->parseObjectTypeDefinition();
        return new TypeExtensionDefinitionNode(['definition' => $definition, 'loc' => $this->loc($start)]);
    }