Package body variables are not allowed as FETCH targets

SET sql_mode=ORACLE;

DROP PACKAGE pkg;

DELIMITER /

CREATE PACKAGE pkg AS

  FUNCTION f1 RETURN INT;

END;

/

CREATE PACKAGE BODY pkg AS

  vc INT := 0;

  FUNCTION f1 RETURN INT AS

    CURSOR cur IS SELECT 1 AS c FROM DUAL;

  BEGIN

    OPEN cur;

    FETCH cur INTO vc; -- error happens here

    CLOSE cur;

    RETURN vc;

  END;

END;

/

DELIMITER ;

SELECT pkg.f1() FROM DUAL;

ERROR 1327 (42000): Undeclared variable: vc

DROP PACKAGE pkg;

CREATE PACKAGE pkg AS

  FUNCTION f1 RETURN INT;

END;

/

CREATE PACKAGE BODY pkg AS

  vc INT := 0;

  FUNCTION f1 RETURN INT AS

    CURSOR cur IS SELECT 1 AS c FROM DUAL;

  BEGIN

    OPEN cur;

    FETCH cur INTO vc;

    CLOSE cur;

    RETURN vc;

  END;

END;

/

SELECT pkg.f1() FROM DUAL;

+----------+

| PKG.F1() |

+----------+

|        1 |

+----------+