ghc: panic! mkUsageInfo: internal name? constr_a2Py{v}

I apply this patch (also hopefully attached) to http://hackage.haskell.org/package/syb-with-class

--- syb-with-class-0.6.1.1-orig/syb-with-class.cabal	2010-11-16 19:41:26.000000000 +1100
+++ syb-with-class-0.6.1.1/syb-with-class.cabal	2011-07-31 01:44:18.356801182 +1000
@@ -25,7 +25,7 @@
   location: http://patch-tag.com/r/Saizan/syb-with-class/
 
 Library 
-    Build-Depends:      base >= 3 && < 5, template-haskell >= 2.4 && < 2.6, bytestring, array, containers
+    Build-Depends:      base >= 3 && < 5, template-haskell >= 2.4 && < 2.7, bytestring, array, containers
     Exposed-modules:
         Data.Generics.SYB.WithClass.Basics
         Data.Generics.SYB.WithClass.Context
--- syb-with-class-0.6.1.1-orig/Data/Generics/SYB/WithClass/Instances.hs	2010-11-16 19:41:26.000000000 +1100
+++ syb-with-class-0.6.1.1/Data/Generics/SYB/WithClass/Instances.hs	2011-07-31 01:44:38.367318167 +1000
@@ -724,4 +724,4 @@
 ------------------------------------------------------------------------------
 
 $( deriveData [''ByteString] )
-$( deriveData [''L.ByteString] )
+-- $( deriveData [''L.ByteString] )

ghc 7.2 rc1 encounters this compile time error:

runghc ./Setup.hs build
Building syb-with-class-0.6.1.1...
Preprocessing library syb-with-class-0.6.1.1...
[1 of 4] Compiling Data.Generics.SYB.WithClass.Context ( Data/Generics/SYB/WithClass/Context.hs, dist/build/Data/Generics/SYB/WithClass/Context.o )
[2 of 4] Compiling Data.Generics.SYB.WithClass.Basics ( Data/Generics/SYB/WithClass/Basics.hs, dist/build/Data/Generics/SYB/WithClass/Basics.o )
[3 of 4] Compiling Data.Generics.SYB.WithClass.Derive ( Data/Generics/SYB/WithClass/Derive.hs, dist/build/Data/Generics/SYB/WithClass/Derive.o )

Data/Generics/SYB/WithClass/Derive.hs:26:1:
    Warning: In the use of `mkTyCon'
             (imported from Data.Generics.SYB.WithClass.Basics, but defined in Data.Typeable):
             Deprecated: "either derive Typeable, or use mkTyCon3 instead"
[4 of 4] Compiling Data.Generics.SYB.WithClass.Instances ( Data/Generics/SYB/WithClass/Instances.hs, dist/build/Data/Generics/SYB/WithClass/Instances.o )
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package array-0.3.0.3 ... linking ... done.
Loading package containers-0.4.1.0 ... linking ... done.
Loading package pretty-1.1.0.0 ... linking ... done.
Loading package template-haskell ... linking ... done.
Loading package bytestring-0.9.2.0 ... linking ... done.
Loading package ffi-1.0 ... linking ... done.

Data/Generics/SYB/WithClass/Instances.hs:9:1:
    Warning: In the use of `mkTyCon'
             (imported from Data.Generics.SYB.WithClass.Basics, but defined in Data.Typeable):
             Deprecated: "either derive Typeable, or use mkTyCon3 instead"

Data/Generics/SYB/WithClass/Instances.hs:14:1:
    Warning: The import of `Data.ByteString.Lazy' is redundant
               except perhaps to import instances from `Data.ByteString.Lazy'
             To import instances alone, use: import Data.ByteString.Lazy()
ghc: panic! (the 'impossible' happened)
  (GHC version 7.2.0.20110728 for x86_64-unknown-linux):
	mkUsageInfo: internal name? constr_aaER{v}

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug


Compilation exited abnormally with code 1 at Sun Jul 31 01:55:25