TH fails to recover from reifyFixity with -fexternal-interpreter

(Originally reported at https://github.com/glguy/th-abstraction/issues/53.)

If you compile the following program:

{-# LANGUAGE TemplateHaskell #-}
module Bug where

import Language.Haskell.TH

main :: IO ()
main = putStrLn $(recover (stringE "reifyFixity failed")
                          (do foo <- newName "foo"
                              _ <- reifyFixity foo
                              stringE "reifyFixity successful"))

It will work fine without the use of -fexternal-interpreter. However, using -fexternal-interpreter will result in an error:

$ /opt/ghc/8.4.3/bin/ghc Bug.hs -fforce-recomp
[1 of 1] Compiling Bug              ( Bug.hs, Bug.o )
$ /opt/ghc/8.4.3/bin/ghc Bug.hs -fforce-recomp -fexternal-interpreter
[1 of 1] Compiling Bug              ( Bug.hs, Bug.o )

Bug.hs:7:19: error:
    • The exact Name ‘foo_a3MT’ is not in scope
        Probable cause: you used a unique Template Haskell name (NameU), 
        perhaps via newName, but did not bind it
        If that's it, then -ddump-splices might be useful
    • In the untyped splice:
        $(recover
            (stringE "reifyFixity failed")
            (do foo <- newName "foo"
                _ <- reifyFixity foo
                stringE "reifyFixity successful"))
  |
7 | main = putStrLn $(recover (stringE "reifyFixity failed")
  |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^...

Bug.hs:7:19: error:
    • The exact Name ‘foo_a3MT’ is not in scope
        Probable cause: you used a unique Template Haskell name (NameU), 
        perhaps via newName, but did not bind it
        If that's it, then -ddump-splices might be useful
    • In the untyped splice:
        $(recover
            (stringE "reifyFixity failed")
            (do foo <- newName "foo"
                _ <- reifyFixity foo
                stringE "reifyFixity successful"))
  |
7 | main = putStrLn $(recover (stringE "reifyFixity failed")
  |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^...

Trac metadata

Trac field	Value
Version	8.4.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture