ghc-6.4.20050220: panic! eval_data2tag...

[Thomas Hallgren]

Hi,

I managed to distill my program into to the following small example that 
still exhibits the problem:

    module Bug where
    data S e = A | B | C | D | E | F | G | H | I deriving (Eq)
    newtype R = T (S R) deriving (Eq)

The output from 'ghc -c -O Bug.hs' is:

ghc-6.4.20050220: panic! (the `impossible' happened, GHC version 
6.4.20050220):
        eval_data2tag
    GHCziPrim.dataToTagzh{(w) v 95f}
      @ (Bug.S{tc r14v} <recnt>Bug.R{tc r14r})
      (__coerce (Bug.S{tc r14v} <recnt>Bug.R{tc r14r}) a{v s1Cm})

Please report it as a compiler bug to glasgow-haskell-bugs at haskell.org,
or http://sourceforge.net/projects/ghc/.

-- 
Thomas Hallgren