[GHC] #8011: -ddump-minimal-imports creates incorrect imports for associated types

22 Jun 2013

      #8011: -ddump-minimal-imports creates incorrect imports for associated types
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Reporter:  dsf               |          Owner:                  
    Type:  bug               |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  7.6.3             |       Keywords:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
 Failure:  None/Unknown      |      Blockedby:                  
Blocking:                    |        Related:                  
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 If you have a module URL.hs:
 {{{
 {-# LANGUAGE TypeFamilies #-}

 module URL (ToURL(toURL, nullURL, errorURL), URLT) where

 class ToURL a where
     type URLT a
     toURL :: a -> URLT a
     nullURL :: a
     errorURL :: a -> URLT a
 }}}
 And a module that uses it Tmp.hs:
 {{{
 {-# LANGUAGE FlexibleContexts #-}
 module Tmp ( clean ) where

 import Data.Char (isAlphaNum)
 import Data.List (dropWhile)
 import URL

 clean :: (ToURL url, Show (URLT url)) => url -> String
 clean = filter isAlphaNum . show . toURL
 }}}
 when you run {{{ghc -ddump-minimal-imports Tmp.hs}}} the resulting
 {{{Tmp.imports}}} will contain the line
 {{{
 import URL ( ToURL(URLT, toURL) )
 }}}
 but it should contain
 {{{
 import URL ( ToURL(toURL), URLT )
 }}}
 This affects both associated type and associated type synonym
 declarations.

-- 
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/8011
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