Matching on pattern synonym succeeds compiled with ghc, fails with ghci

A file /tmp/test.hs

{-# Language PatternSynonyms, ViewPatterns #-}

pattern Parsed x = [(x, "")]
pattern Read a <- (reads -> Parsed a)

main = do
  let Read x = "420"
  print (x::Int)

$ ghc -ignore-dot-ghci /tmp/test.hs && /tmp/test 
420

fails with ghci

$ ghci -ignore-dot-ghci /tmp/test.hs 
GHCi, version 8.0.0.20160511: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( /tmp/test.hs, interpreted )
ghc: panic! (the 'impossible' happened)
  (GHC version 8.0.0.20160511 for x86_64-unknown-linux):
        kindPrimRep.go rep_a1XC

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

> 

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	mpickering
Operating system
Architecture