More about finding the source of fromJust Nothing.
For g n = fromJust $ f n,
ghc-6.6 often looses the reference to f in its run-time error
report -- when f returns Nothing.
And this is difficult to locate the source.
But one could write
g n = let Just m = f n in m,
for which GHC reports
Main: M1.hs:9:11-22:
Irrefutable pattern failed for pattern Data.Maybe.Just m
-- it points to the source line!
-----------------
Serge Mechveliani
[EMAIL PROTECTED]
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