Duplicate symbols generated when Generics flag and syb-with-class "derive" used simultaneously

Attached file Foo.hs compiles fine using

ghc -c Foo.hs

But compiling using the -XGenerics flag yields duplicate symbols errors from the assembler:

jcheney@oreb:~/src/FreshLib/bug$ ghc -c -v -XGenerics Foo.hs
Glasgow Haskell Compiler, Version 6.10.1, for Haskell 98, stage 2 booted by GHC version 6.6
Using package config file: /usr/local/lib/ghc-6.10.1/./package.conf
Using package config file: /home/jcheney/.ghc/i386-linux-6.10.1/package.conf
hiding package base-3.0.3.0 to avoid conflict with later version base-4.0.0.0
wired-in package ghc-prim mapped to ghc-prim-0.1.0.0
wired-in package integer mapped to integer-0.1.0.0
wired-in package base mapped to base-4.0.0.0
wired-in package rts mapped to rts-1.0
wired-in package haskell98 mapped to haskell98-1.0.1.0
wired-in package syb mapped to syb-0.1.0.0
wired-in package template-haskell mapped to template-haskell-2.3.0.0
wired-in package dph-seq mapped to dph-seq-0.3
wired-in package dph-par mapped to dph-par-0.3
Hsc static flags: -static
Created temporary directory: /tmp/ghc15945_0
*** Checking old interface for main:Foo:
*** Parser:
*** Renamer/typechecker:
*** Simplify:
*** CorePrep:
*** ByteCodeGen:
Loading package ghc-prim ... linking ... done.
Loading package integer ... linking ... done.
Loading package base ... linking ... done.
Loading package syb ... linking ... done.
Loading package base-3.0.3.0 ... linking ... done.
Loading package array-0.2.0.0 ... linking ... done.
Loading package packedstring-0.1.0.1 ... linking ... done.
Loading package containers-0.2.0.0 ... linking ... done.
Loading package pretty-1.0.1.0 ... linking ... done.
Loading package template-haskell ... linking ... done.
Loading package bytestring-0.9.1.4 ... linking ... done.
Loading package syb-with-class-0.4 ... linking ... done.
*** Desugar:
    Result size = 230
*** Simplify:
    Result size = 141
    Result size = 141
*** Tidy Core:
    Result size = 141
writeBinIface: 9 Names
writeBinIface: 42 dict entries
*** CorePrep:
    Result size = 187
*** Stg2Stg:
*** CodeGen:
*** CodeOutput:
*** Assembler:
gcc -I. -c /tmp/ghc15945_0/ghc15945_0.s -o Foo.o
/tmp/ghc15945_0/ghc15945_0.s: Assembler messages:

/tmp/ghc15945_0/ghc15945_0.s:224:0:
     Error: symbol `Foo_zdgtoFoo_closure' is already defined

/tmp/ghc15945_0/ghc15945_0.s:233:0:
     Error: symbol `Foo_zdgtoFoo_info' is already defined

/tmp/ghc15945_0/ghc15945_0.s:273:0:
     Error: symbol `Foo_zdgfromFoo_closure' is already defined

/tmp/ghc15945_0/ghc15945_0.s:291:0:
     Error: symbol `Foo_zdgfromFoo_info' is already defined
*** Deleting temp files:
Deleting: /tmp/ghc15945_0/ghc15945_0.s
*** Deleting temp dirs:
Deleting: /tmp/ghc15945_0

Trac metadata

Trac field	Value
Version	6.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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