typecheck/TcTyClsDecls.lhs: Non-exhaustive patterns in function tcConDecl

The following code

module Main where

newtype Test where
    T :: Int -> Test

instance Show Test where
    show (T i) = show i

main = putStrLn (show (T 3))

causes the compiler to crash with:

[1 of 1] Compiling Main             ( test2.hs, test2.o )
ghc-6.6: panic! (the 'impossible' happened)
  (GHC version 6.6 for powerpc-apple-darwin):
        typecheck/TcTyClsDecls.lhs:(468,0)-(524,4): Non-exhaustive patterns in function tcConDecl


Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

however changing 'newtype' to 'data' compiles without errors.

Tested with GHC and GHCi 6.6 under Mac OS X 10.4.8 running on an iMac G5.

Trac metadata

Trac field	Value
Version	6.6
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown
Architecture	Unknown