I have the following Haskell modules: <genCG.hs> {-# OPTIONS -fglasgow-exts #-} module GenCG where gdecls pbname pbniname = [d| valGetter pbname = "Get" ++ $pbniname valSetter pbname = "Set" ++ $pbniname fldGetter pbname = "Get" ++ $pbniname ++ "Field" fldSetter pbname = "Set" ++ $pbniname ++ "Field" arrGetter pbname = "Get" ++ $pbniname ++ "ArrayItem" arrSetter pbname = "Set" ++ $pbniname ++ "ArrayItem" gvarGetter pbname = "Get" ++ $pbniname ++ "GlobalVar" gvarSetter pbname = "Set" ++ $pbniname ++ "GlobalVar" svarGetter pbname = "Get" ++ $pbniname ++ "SharedVar" svarSetter pbname = "Set" ++ $pbniname ++ "SharedVar" |] </genCG.hs> and <spliceCG.hs> {-# OPTIONS -fglasgow-exts #-} module SpliceCG where import GenCG $(gdecls "integer" [| "Int" |]) $(gdecls "unsignedinteger" [| "Uint" |]) </spliceCG.hs> Trying to compile 'spliceCG.hs' I'm recieving the following: Loading package base-1.0 ... linking ... done. Loading package haskell98-1.0 ... linking ... done. Loading package template-haskell-1.0 ... linking ... done. ghc.EXE: panic! (the `impossible' happened, GHC version 6.4): plusProv SpliceCG SpliceCG Please report it as a compiler bug to glasgow-haskell-bugs@haskell.org, or http://sourceforge.net/projects/ghc/. If I splice in a single declaration, for example: <spliceCG.hs> {-# OPTIONS -fglasgow-exts #-} module SpliceCG where import GenCG $(gdecls "integer" [| "Int" |]) </spliceCG.hs> it is compiled just fine.