#3418: Equality constraint causes ghc panic
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Reporter: blarsen | Owner:
Type: bug | Status: new
Priority: normal | Component:
Compiler
Version: 6.10.4 | Severity: normal
Keywords: type families, equality constraint, panic | Testcase:
Os: Linux | Architecture: x86_64
(amd64)
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I have the following module:
{{{
{-# LANGUAGE TypeFamilies #-}
module GhcBug where
newtype (a ~ b) => S a b = S { unS :: a }
}}}
Loading this in ghci results in this:
{{{
> :l GhcBug
[1 of 1] Compiling GhcBug ( GhcBug.hs, interpreted )
ghc: panic! (the 'impossible' happened)
(GHC version 6.10.4 for x86_64-unknown-linux):
typePrimRep <pred>a{tv a1MH} [tv] ~ b{tv a1MI} [tv]
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3418>
GHC <http://www.haskell.org/ghc/>
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