#7053: Panic with PolyKinds + GADTs
------------------------------+---------------------------------------------
Reporter: dreixel | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.5 | Keywords: PolyKinds
Os: Unknown/Multiple | Architecture: Unknown/Multiple
Failure: None/Unknown | Testcase:
Blockedby: | Blocking:
Related: |
------------------------------+---------------------------------------------
This works:
{{{
data TypeRep (a :: k) :: * where
TyApp :: TypeRep a -> TypeRep b -> TypeRep (a b)
}}}
Whereas this (removing the obvious return kind of the datatype):
{{{
data TypeRep (a :: k) where
TyApp :: TypeRep a -> TypeRep b -> TypeRep (a b)
}}}
Gives this panic:
{{{
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 7.5 for i386-unknown-linux):
metaTvRef
<<details unavailable>>
}}}
(The example is pretty much taken from Weirich, Hsu, and Eisenberg, but I
haven't seen it reported here yet.)
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7053>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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