Template Haskell crashes

The following fragment:

{-# LANGUAGE TemplateHaskell #-}

import Language.Haskell.TH

foo = $(return $ 
    CompE
        [NoBindS (VarE $ mkName "undefined")
        ,BindS (VarP $ mkName "r1") (VarE $ mkName "undefined") ])

when loaded gives:

*** Exception: hsSyn\Convert.lhs:(427,14)-(428,33): Non-exhaustive patterns in case

Trac metadata

Trac field	Value
Version	6.10.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	ndmitchell@gmail.com
Operating system
Architecture