#5287: The 'impossible' happened. solveDerivEqns: probable loop --------------------------+------------------------------------------------- Reporter: agocorona | Owner: Type: bug | Status: new Priority: normal | Component: Compiler Version: 7.0.3 | Keywords: solveDerivEqns Testcase: | Blockedby: Os: Windows | Blocking: Architecture: x86 | Failure: Compile-time crash --------------------------+------------------------------------------------- This code:
--------- begin of code------ {-# LANGUAGE FlexibleInstances, UndecidableInstances , MultiParamTypeClasses #-} class Serializable a b class IResource a --The rest of the instance definitions does not matter for the error instance Serializable a b => IResource a data DBRef a= DBRef String a instance (IResource a) => Read (DBRef a) data Votation a= Votation{ content :: DBRef a } deriving (Read) ------------------------------- end of code --- gives the following error at compilation time: tests>runghc impossiblelloop.hs ghc: panic! (the 'impossible' happened) (GHC version 7.0.3 for i386-unknown-mingw32): solveDerivEqns: probable loop (impossiblelloop.hs:20:13-16 main:Main.$fReadVotation{v rhI} [a{tv abB} [tv] ] base:GHC.Read.Read{tc 2d} [main:Main.Votation{tc rbo} a{tv abB} [tv]] = [base:GHC.Read.Read{tc 2d} (main:Main.DBRef{tc rbu} a{tv abB} [tv])]) [[main:Main.Serializable{tc rbA} a{tv abB} [tv] b{tv ajE} [tcs]]] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5287> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs