ghc crash from kinds

When I run this in ghci:

let x :: MaybeT IO (Ptr Int);  x = (lift newCString "hi")  >>= nullableToMaybeT

I get this output:

    Couldn't match kind `* -> *' with `*'
    Expected type: [Char] -> MaybeT IO (Ptr Int)
      Actual type: [Char] -> MaybeT IO (Ptr Int)
    Kind incompatibility when matching types:
      [Char] :: * -> *
      [Char] :: *
    The function `lift'ghc: panic! (the 'impossible' happened)
  (GHC version 7.6.3 for x86_64-apple-darwin):
        kindFunResult
<<details unavailable>>

where nullToMaybeT is:

nullableToMaybeT :: Monad m => Ptr a -> MaybeT m (Ptr a)
nullableToMaybeT ptr = do
  case (ptr == nullPtr) of
    True ->  (MaybeT . return) Nothing
    False -> return ptr

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	lowest
Resolution	Unresolved
Component	Compiler
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