Panic compiling singletons: StgCmmEnv: variable not found

cabal install singletons panics like this with HEAD:

ghc: panic! (the 'impossible' happened)
  (GHC version 7.11.20150313 for x86_64-unknown-linux):
        StgCmmEnv: variable not found
  cobox_a1Job
  local binds for:
  sConst
  sAsTypeOf
  sId
  %:++
  sMap
  sFoldr
  %$
  %$!
  $WLet_1627796109GoSym3KindInference
  $WLet_1627796109GoSym2KindInference
  $WLet_1627796109GoSym1KindInference
  $WLet_1627796109GoSym0KindInference
  $WSeqSym1KindInference
  $WSeqSym0KindInference
  $WFlipSym2KindInference
  $WFlipSym1KindInference
  $WFlipSym0KindInference
  $WConstSym1KindInference
  $WConstSym0KindInference
  $WAsTypeOfSym1KindInference
  $WAsTypeOfSym0KindInference
  $WIdSym0KindInference
  $W:++$###
  $W:++$$###
  $WMapSym0KindInference
  $WMapSym1KindInference
  $WFoldrSym2KindInference
  $WFoldrSym1KindInference
  $WFoldrSym0KindInference
  $WLambda_1627796009Sym3KindInference
  $WLambda_1627796009Sym2KindInference
  $WLambda_1627796009Sym1KindInference
  $WLambda_1627796009Sym0KindInference
  $W:.$$$###
  $W:.$$###
  $W:.$###
  %$1
  sAsTypeOf1
  sConst1
  sFlip1
  sId1
  sSeq1
  a_r1JEg
  sF_s1JFN
  sG_s1JFO
  sA_1627796004_s1JFP

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

Trac metadata

Trac field	Value
Version	7.11
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (CodeGen)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	simonmar
Operating system
Architecture