id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
1213,typecheck/TcTyClsDecls.lhs: Non-exhaustive patterns in function tcConDecl,guest,,"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.",bug,closed,normal,,Compiler,6.6,fixed,,,Unknown/Multiple,Unknown/Multiple,,Unknown,,,,