#5333: Arrow command combinators and infixr cause the desugarer to fail
---------------------------------+------------------------------------------
Reporter: peteg | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler (Parser)
Version: 7.0.3 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: GHC rejects valid program
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The following code exhibits the bug:
{{{
{-# LANGUAGE Arrows, NoMonomorphismRestriction #-}
module T where
import Prelude hiding ( id, (.) )
import Control.Arrow
cc1 :: Arrow a => a e b -> a e b -> a e b
cc1 = undefined
-- 'g' fails to compile.
-- g = proc (x, y, z) ->
-- ((returnA -< x) &&& (returnA -< y) &&& (returnA -< z))
-- 'f' compiles:
-- - without an infix declaration
-- - with the infixl declaration
-- and fails with the infixr declaration
infixr 6 `cc1`
-- infixl 6 `cc1`
f = proc (x, y, z) ->
((returnA -< x) `cc1` (returnA -< y) `cc1` (returnA -< z))
}}}
GHC says:
{{{
ghc: panic! (the 'impossible' happened)
(GHC version 7.0.3 for i386-apple-darwin):
dsSyntaxTable Not found: base:GHC.Desugar.>>>{v 01W}
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5333>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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