Missing instance of MonadFix for Q

Q is capable of being an instance of MonadFix. The definition of mfix is the same as fixIO except that the MVar handling is wrapped in runIO.

instance MonadFix Q where
  mfix k = do
    m <- runIO newEmptyMVar
    ans <- runIO (unsafeInterleaveIO (takeMVar m))
    result <- k ans
    runIO (putMVar m result)
    pure result

Trac metadata

Trac field	Value
Version
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
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