Segfault when using Rel8 with a mixture of object- and byte-code in GHCi

Summary

This was first reported on the rel8 issue tracker.

Users ran into a segfault when using the library in GHCi with a mixture of object code and byte code.

For context, rel8 uses HKD and generics to turn monadic Haskell code into a ByteString of SQL via the opaleye library.

Steps to reproduce

@ulidtko produced the following reproducer. Note this depends on quite a few libraries through rel8, so it could do with some further minimization:

{-# LANGUAGE PackageImports #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE DisambiguateRecordFields #-}
module Main where

import "base" Prelude
import "rel8" Rel8

test :: Insert ()
test = Insert { into=schema, rows=mempty, onConflict=DoNothing, returning=NoReturning }
  where
    schema :: TableSchema (Name String, Name String)
    schema = TableSchema {name="test", columns=("colA","colB")}

main :: IO ()
main = crash where crash = putStrLn . showInsert $ test

-- runs normally when compiled
-- runs normally in ghci with :set -fobject-code
-- runs normally when the entire rel8 package is ghci-loaded as interpreted
-- SIGSEGV in ghci (cabal repl/stack repl/runhaskell) if interpreted + rel8 compiled

Expected behavior

No segfaults

Environment

• GHC version used: ghc-9.6.4, ghc-9.10.1

This occurs both on x86_64-linux and x86_64-darwin.