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 |