Unexpected DataKind Panic
Here's a simplified version of a panic I'm getting:
{-# LANGUAGE RankNTypes, GADTs, DataKinds, PolyKinds, TypeOperators, TypeFamilies #-}
import Data.Proxy
data Want :: (i,j) -> * where
Want :: (a ~ '(b,c) => Proxy b) -> Want a
GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
ghc: panic! (the 'impossible' happened)
(GHC version 7.8.2 for x86_64-apple-darwin):
tcTyVarDetails k{tv aAv} [tv]
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
Trac metadata
Trac field | Value |
---|---|
Version | 7.8.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | ekmett |
Operating system | |
Architecture |