Error: undefined symbols e__zk2__df_A_LArith_G

[Jan Krynicky]

Could please someone help me?

Simplified example:
-----zk2.dcl
definition module zk2

import StdClass

f::a -> a | MultDiv a

-----
-----zk3.dcl
definition module zk3

import StdClass

g::a -> a | Arith a

-----
-----zk3.icl
implementation module zk3

import StdClass,zk2
//...
g::a -> a | Arith a
g x = abs(x + f x)
//...
-----
-----zk.icl
module zk

import zk2,zk3
//...
Start = g 5

-----

Gives me (after attempt to run it!)
Error: the following symbols are undefined:
e__zk2__df_A_LArith_G

So, what to do.  
(I'd prefer not to change the type of "f" to "::a -> a | Arith a")
Changing "g" to "::a -> a | Arith a & MultDiv a"  makes no good.


Jenda--------------------------------------------------------
Jan Krynicky  -  JKRY3025@COMENIUS.MFF.CUNI.CZ
student of Faculty of Mathematics and Physics
Charles University in Prague
http://www.ms.mff.cuni.cz/acad/webik/~jkry3025