[jhc] got other error after splitting into more modules, jhc: src/E/TypeAnalysis.hs:415:12-31: Irrefutable pattern failed for pattern Data.Maybe.Just vp

[AR]

Hello List,

after splitting my module futher i got the following error (see below.)
(Btw. I only used very basic haskell functions and no haskell extentions

Base.hs:import List
Helper.hs:import List
Main.hs:import Debug.Trace (trace)
Main.hs:import Helper
Main.hs:import List
Main.hs:import Maybe
Main.hs:import System.Random
Main.hs:import System.Time
RandomHelper.hs:import System.Random
)

$ jhc Main.hs
jhc Main.hs
jhc 0.7.6 (0.7.6-3)
Finding Dependencies...
Using Ho Cache: '/Users/klausmeier/.jhc/cache'
Main                    [Main.hs]
Base                    [./Base.hs]
Helper                  [./Helper.hs]
RandomHelper            [./RandomHelper.hs]
Typechecking...
[1 of 4] RandomHelper      
(.............................................)
[2 of 4] Helper            
(.............................................)
[3 of 4] Base              
(.............................................)
[4 of 4] Main              
(.............................................)
Main.hs:402 - Warning: defaulting:  t688 => Jhc.Basics.Integer
Main.hs:451 - Warning: defaulting:  t333 => Jhc.Basics.Integer
Main.hs:451 - Warning: defaulting:  t372 => Jhc.Basics.Integer
Main.hs:470 - Warning: defaulting:  t233 => Jhc.Basics.Integer
Compiling...
[1 of 4] Helper            
<..............................www.....ww..........>
[2 of 4] Base              
<.............*............www.w....wwww.wwww.wwwww>
[3 of 4] RandomHelper      
<..........................................wwwwwwww>
[4 of 4] Main             <..........................w.ww.www.wwww.ww.wwww 
.w.>
Collected Compilation...
-- typeAnalyzeMethods
jhc: src/E/TypeAnalysis.hs:415:12-31: Irrefutable pattern failed for  
pattern Data.Maybe.Just vp

Greeting, Alf