Template Haskell conversion fails with "malformed type"

Nicholas Frisby writes: When using Template Taskell (via Derive) to generate this (exact) instance:

  instance Foldable ((->) Int) => Foldable Data.Derivable.InterpreterLib.Test.List
      where foldMap f (Cons x0 x1) = (const mempty Cons `mappend` foldMap f x0)
                                      `mappend` foldMap f x1
            foldMap f (Nil) = const mempty Nil

I realize the context is unsatisfiable. My issue, is that I can't even reach that "challenge". I get this error instead:

   Malformed type AppT ArrowT (ConT GHC.Base.Int)
    When splicing generated code into the program

Trac metadata

Trac field	Value
Version	6.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
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Blocking
CC	nicolas.frisby@gmail.com
Operating system
Architecture