I have code like:

let baseTex = 
  (getTexPropNode nodes . NC.properties . NC.av $ geometry) 
  >>= baseTex 
  >>= (flip Map.lookup texs) . NC.tdSource

which gives me error:

Games/secunda/Graph.hs:224:23:
    Couldn't match expected type `TexProperty -> Maybe a0'
                with actual type `Maybe b0'
    In the second argument of `(>>=)', namely `baseTex'
    In the first argument of `(>>=)', namely
      `(getTexPropNode nodes . NC.properties . NC.av $ geometry)
       >>= baseTex'
    In the expression:
      (getTexPropNode nodes . NC.properties . NC.av $ geometry)
      >>= baseTex
      >>= (flip Map.lookup texs) . NC.tdSource

However if I try to get type of expressin on the right hand side of let baseTex = ... in ghci then I get no error. Problem is that I am importing module with function baseTex :: TexProperty -> Maybe TexDesc and that function is shadowed by let expression which should have type of Maybe Texture.

I tried to use ghc-options: -Wall -fwarn-name-shadowing in Cabal with no effect.

From above error I conclude, that I made a type error. So I try to get type of expression in ghci which results in correct type - that makes my confusion. While I am trying to concentrate on type error, I am missing that I shadowed function by variable.

This is not for the first time I've done same mistake. I would appreciate to get warnings about name shadowing since they makes me belief that I am using names of different type.