Type families, holes and -fdefer-type-errors may cause 'opt_univ fell into a hole' panic

This program, when compiled like ghc -fdefer-type-errors -c panic.hs:

{-# LANGUAGE TypeFamilies #-}

module MorePanic where

transitive :: (a, b) -> (b, c) -> (a, c)
transitive = undefined

trigger :: a -> b -> (F a b, F b a)
trigger _ _ = _ `transitive` trigger _ _

type family F (n :: *) (m :: *) :: *

Gives this panic after several error messages:

ghc.EXE: panic! (the 'impossible' happened)
  (GHC version 8.4.3 for x86_64-unknown-mingw32):
	opt_univ fell into a hole
  {co_a7Sj}
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler\utils\Outputable.hs:1150:37 in ghc:Outputable
        pprPanic, called at compiler\\types\\OptCoercion.hs:242:5 in ghc:OptCoercion

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

This bug also affects GHCi. Attached is full output

Trac metadata

Trac field	Value
Version	8.4.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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