unexpected ambiguity
wizztick-ghc at douma.eu.org
wizztick-ghc at douma.eu.org
Mon Apr 10 10:53:34 EDT 2006
Niklas Sorensson wrote:
> Main.hs:8:15:
> Ambiguous occurrence `lift'
> It could refer to either `Control.Monad.Trans.lift', ...
> or `Apa.lift', imported from Apa at ...
>
> Is this correct? I would have expected that an unqualified lift could only
> refer to the one exported from Apa in this case.
The error is correct. The module Control.Monad.State re-export the lift
identifier from Control.Monad.Trans.
Thus the line 'import Control.Monad.State' is the evildoer. Use for
example:
import Control.Monad.State hiding (lift)
The error message surly makes you look in the wrong direction.
Cheers,
Christof
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