id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
5533	panic! (the 'impossible' happened) ...   splitFunTy ...	guest	simonpj	"""MyModule.hs"" containing these four lines:
{{{
module MyModule where
data T a = CT {f1 :: Int -> a, f2 :: Double}
f2 :: Int -> Double
g x = CT {f1 = \t -> f2 t + x, f2 = x}
}}}

yields:
{{{
C:\Tasks\Task_IsolateGhcBug>ghc --make MyModule.hs -v
Glasgow Haskell Compiler, Version 7.0.3, for Haskell 98, stage 2 booted by GHC version 6.12.2
Using binary package database: C:\Programme\Haskell Platform\2011.2.0.1\lib\package.conf.d\package.cache
wired-in package ghc-prim mapped to ghc-prim-0.2.0.0-e1f7c380581d61d42b0360d440cc35ed
wired-in package integer-gmp mapped to integer-gmp-0.2.0.3-91607778cf3ae8f3948a50062b4f8479
wired-in package base mapped to base-4.3.1.0-f520cd232cc386346843c4a12b63f44b
wired-in package rts mapped to builtin_rts
wired-in package template-haskell mapped to template-haskell-2.5.0.0-7d9b1443ac5ab69e5ed705a487990deb
wired-in package dph-seq not found.
wired-in package dph-par not found.
Hsc static flags: -static
*** Chasing dependencies:
Chasing modules from: *MyModule.hs
Stable obj: []
Stable BCO: []
Ready for upsweep
  [NONREC
      ModSummary {
         ms_hs_date = Thu Oct  6 19:01:55 Westeuropäische Sommerzeit 2011
         ms_mod = main:MyModule,
         ms_imps = [import Prelude]
         ms_srcimps = []
      }]
compile: input file MyModule.hs
Created temporary directory: C:\Temp\ghc4956_0
*** Checking old interface for main:MyModule:
[1 of 1] Compiling MyModule         ( MyModule.hs, MyModule.o )
*** Parser:
*** Renamer/typechecker:
*** Desugar:
*** Deleting temp files:
Deleting: C:\Temp\ghc4956_0\ghc4956_0.s
Warning: deleting non-existent C:\Temp\ghc4956_0\ghc4956_0.s
*** Deleting temp dirs:
Deleting: C:\Temp\ghc4956_0
ghc: panic! (the 'impossible' happened)
  (GHC version 7.0.3 for i386-unknown-mingw32):
        splitFunTy
    forall a{tv aby} [tv].
    main:MyModule.T{tc rbp} a{tv aby} [tv]
    -> ghc-prim:GHC.Types.Double{(w) tc 3u}

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
}}}"	bug	closed	normal		Compiler	7.0.3	fixed	splitFunTy		Unknown/Multiple	Unknown/Multiple	None/Unknown		rename/should_fail/T5533