Type family and GADT error
This bug was posted to glasgow-haskell-users@haskell.org by Roberto Zunino, archived at http://www.haskell.org/pipermail/glasgow-haskell-users/2007-September/013149.html I am copying the post with the bug into trac:
Here's unsafeCoerce:
type family Const a type instance Const a = ()
data T a where T :: a -> T (Const a)
coerce :: forall a b . a -> b coerce x = case T x :: T (Const b) of T y -> y
And this indeed "works"... Here's the result with the latest RC:
- TypeFam> coerce () 2
<interactive>: internal error: stg_ap_v_ret
(GHC version 6.9.20070918 for x86_64_unknown_linux)
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
Aborted
Regards, Zun.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 6.9 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | high |
| Resolution | Unresolved |
| Component | Compiler (Type checker) |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | Unknown |
| Architecture | Unknown |