-fdefer-typed-holes causes panic on unbound variable

module Main where

main = do
    print v
    return ()

Compile it without -fdefer-typed-holes and it fails as expected:

➜  hole_bug ghc --make Main.hs -fforce-recomp 
[1 of 1] Compiling Main             ( Main.hs, Main.o )

Main.hs:4:11: error: Variable not in scope: v

Adding -fdefer-typed-holes is causing a panic instead of runtime error:

➜  hole_bug ghc --make Main.hs -fforce-recomp -fdefer-typed-holes
[1 of 1] Compiling Main             ( Main.hs, Main.o )

Main.hs:4:11: warning: [-Wtyped-holes] Variable not in scope: v
ghc: panic! (the 'impossible' happened)
  (GHC version 8.0.1 for x86_64-unknown-linux):
        StgCmmEnv: variable not found
  $dShow_aKo
  local binds for:
  $trModule
  $trModule1_r16k
  $trModule2_r16s
  sat_s16x
  sat_s16z

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

Tried with: 8.0.1, HEAD as of today.

Trac metadata

Trac field	Value
Version	8.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
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