Combination of foreign export and template haskell leads to linker error

https://gist.github.com/457065b6ff777f09d862b2e1378d68ab

It seems that if you use a foreign export then you can easily make GHC issue a linker error if you also use template-haskell in the same unit.

ghc P Main foo.c -this-unit-id p1-0 -package-name p1 -odir=dist -hidir=dist -stubdir=dist

In this example, we define a function foo, which is foreign exported and then used in foo.c. The main function contains a TH splice which causes the linker to get invoked and leads to this error:

GHC.Linker.Loader.dynLoadObjs: Loading temp shared object failed
During interactive linking, GHCi couldn't find the following symbol:
  /run/user/1000/ghc2096310_0/libghc_18.so: undefined symbol: foo
This may be due to you not asking GHCi to load extra object files,
archives or DLLs needed by your current session.  Restart GHCi, specifying
the missing library using the -L/path/to/object/dir and -lmissinglibname
flags, or simply by naming the relevant files on the GHCi command line.
Alternatively, this link failure might indicate a bug in GHCi.
If you suspect the latter, please report this as a GHC bug:
  https://www.haskell.org/ghc/reportabug

If you look at the linker command, it includes foo.o, which has an undefined reference to foo, but no the object where foo is defined (dist/P.o).

/nix/store/8pbwywcj6vbswz7xmy2dh716x8blgh8w-gcc-wrapper-9.3.0/bin/cc '-fuse-ld=gold' -Wl,--no-as-needed -o /run/user/1000/ghc2096310_0/libghc_18.so dist/foo.o -shared -Wl,-Bsymbolic -Wl,-h,libghc_18.so -L/nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/base-4.16.0.0 -Xlinker -rpath -Xlinker /nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/base-4.16.0.0 -L/nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/ghc-bignum-1.2 -Xlinker -rpath -Xlinker /nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/ghc-bignum-1.2 -L/nix/store/fphpbj8jpyibz0l2xspidg6s7zm7xyb5-gmp-6.2.0/lib -Xlinker -rpath -Xlinker /nix/store/fphpbj8jpyibz0l2xspidg6s7zm7xyb5-gmp-6.2.0/lib -L/nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/ghc-prim-0.8.0 -Xlinker -rpath -Xlinker /nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/ghc-prim-0.8.0 -L/nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/rts -Xlinker -rpath -Xlinker /nix/store/5qcip2dpaxrlacm0n9gpia4wg9dzlfrl-ghc-9.2.1/lib/ghc-9.2.1/rts -L/nix/store/s0mblhs5vmjza9dmipn74rwqflxy1fw7-libffi-3.3/lib -Xlinker -rpath -Xlinker /nix/store/s0mblhs5vmjza9dmipn74rwqflxy1fw7-libffi-3.3/lib -lHSbase-4.16.0.0-ghc9.2.1 -lHSghc-bignum-1.2-ghc9.2.1 -lHSghc-prim-0.8.0-ghc9.2.1 -lgmp -lc -lm

added needs triage label

removed needs triage label

added Pnormal Tbug driver linking labels

added GHCi label

mentioned in commit 1e9bc5dc

mentioned in merge request !7009 (closed)

There is a comment about this in the cabal source code:

 -- TODO: problem here is we need the .c files built first, so we can load them
  -- with ghci, but .c files can depend on .h files generated by ghc by ffi
  -- exports.
  whenReplLib $ do
    when (null (allLibModules lib clbi)) $ warn verbosity "No exposed modules"
    runGhcProg replOpts

mentioned in commit 5b301d45

mentioned in commit 4c3e2dde

mentioned in commit 983f240f

mentioned in commit ebd52473

mentioned in commit 1d591293

mentioned in commit 14d1ee88

mentioned in commit 0833ad55

mentioned in commit ec28cd28

mentioned in commit 33e75588

mentioned in commit fd42ab5f