Type families bug with data family instances
This data family definition led to the ability to define a generic cast:
{-# LANGUAGE TypeFamilies #-}
data family T a b t
data instance T a b t = L a
data instance T a b () = R b
cast :: a -> b
cast x = let L i = R x in i
get :: IO Char
get = cast ()
This bug was observed in ghc version 6.10.1, 6.10.1.20090326 and 6.10.2.
% ghci test.hs
GHCi, version 6.10.2: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer ... linking ... done.
Loading package base ... linking ... done.
[1 of 1] Compiling Main ( test.hs, interpreted )
Ok, modules loaded: Main.
*Main> get
'\4312564'
*Main> get
<interactive>: internal error: stg_ap_v_ret
(GHC version 6.10.2 for x86_64_unknown_linux)
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
zsh: abort ghci test.hs
Trac metadata
Trac field | Value |
---|---|
Version | 6.10.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |