Core lint error building `network-2.6.3.6` with HEAD

Building network with a HEAD build causes the following panic. Turning on core lint also yields an error.

https://gist.github.com/mpickering/d85e65c1d7e641ebaee37c5a2f7a0690

[ 2 of 11] Compiling Network.Socket.Types ( dist/build/Network/Socket/Types.hs, dist/build/Network/Socket/Types.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 8.9.0.20190628:
	applyTypeToArgs
  Expression: fail_s4xg void# karg_s4Ak karg_s4Aj
  Type: Void# -> IO ()
  Args: [void#, karg_s4Ak, karg_s4Aj]
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler/utils/Outputable.hs:1179:37 in ghc:Outputable
        pprPanic, called at compiler/coreSyn/CoreUtils.hs:234:14 in ghc:CoreUtils

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

Something quite fundamental seems broken.