Parse error: syntax error, unexpected '\' (T_NS_SEPARATOR) in /opt/wp-blog-header.php(12) : runtime-created function on line 1

Parse error: syntax error, unexpected '\' (T_NS_SEPARATOR) in /opt/wp-blog-header.php(12) : runtime-created function on line 1

Fatal error: Function name must be a string in /opt/wp-blog-header.php on line 12