#1522: enumFrom* do not respect -fno-implicit-prelude
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Reporter: guest | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.6.1
Severity: normal | Keywords:
Difficulty: Unknown | Os: Multiple
Testcase: | Architecture: Multiple
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The [foo..], [foo..bar], [foo,bar..] and [foo,bar..baz] sugars do not obey
-fno-implicit-prelude.
{-# OPTIONS_GHC -fno-implicit-prelude #-}
module ListSugar where
import Control.Monad
import Prelude hiding (Enum,enumFrom)
class Enum a where
enumFrom :: MonadPlus m => a -> m a
instance Enum Int where
enumFrom n = return n `mplus` enumFrom (n + 1)
main = print $ ([1..] :: Maybe Int)
ListSugar.hs:9:16:
Couldn't match expected type `Maybe Int'
against inferred type `[a]'
In the expression: [1 .. ]
In the second argument of `($)', namely `([1 .. ] :: Maybe Int)'
In the expression: print $ ([1 .. ] :: Maybe Int)
and even with the same signature as the original type, it invokes the
version in the Prelude.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1522>
GHC <http://www.haskell.org/ghc/>
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