Hi all,
is this a bug or is it by design?

FB2.1 V 6.3.0.17798
WXP

Given MYTABLE
MYFIELD1 int PK
MYFIELD2 int

UPDATE MYTABLE SET MYFIELD2=MYFIELD2+1 WHERE MYFIELD1=1
runs ok

but

UPDATE OR INSERT (MYFIELD1, MYFIELD2) VALUES (1, MYFIELD2+1)

result is

Invalid token.
Dynamic SQL Error.
SQL error code = -104.
Token unknown - line x, column y.
MYFIELD2.

Thanks
Andrea