panic in arrow code "foo = returnA -< []"

The following malformed code causes a panic in ghc 6.2, and some folks
on IRC tried it in various CVS snapshots, where it also breaks.

module Main where
import Control.Arrow

foo = returnA -< []

-----------------------------------------------

ghc -farrows Test.hs
ghc-6.2: panic! (the `impossible' happened, GHC version 6.2):
        tcMonoExpr
    ControlziArrow.returnA {- v r4a -} -< GHCziBase.ZMZN {- d 6m -}


peace,

isaac
-- 
Isaac Jones <isaac.jones@xxxxxxxxxx>
Aetion