ghc panic

I got this error:

ghc: panic! (the 'impossible' happened)
  (GHC version 8.0.2 for x86_64-unknown-mingw32):
        initTc: unsolved constraints
  WC {wc_insol = [W] %_a1El :: t_a1Ek[tau:1] (CHoleCan: %)}

while compiling the following code

halveEvens :: [Integer] -> [Integer]
halveEvens = map . filter (\c -> c%2 == 0)

Trac metadata

Trac field	Value
Version	8.0.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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