haskell.compiler.ghc9*: work around output cycles on aarch64-darwin

Due to link time dead code elimination not working on aarch64-darwin,
some unused store path references in Paths_* modules are retained. This
causes reference cycles when a separate `bin` output is used.

To prevent this, add a patch to Cabal as shipped by GHC which infers
based on the installation layout (which is influenced by
enableSeparateBinOutput, enableSeparateDataOutput etc. in a Nix build)
which references can be retained without causing a reference cycle. This
ensures that packages that were fine with a bin output will also work on
aarch64-darwin. Packages that cause a reference cycle anyways (by
actually using references that do cause one) fail due to a missing
symbol – here we are trading the overall benefit for a more confusing
error message.

For details, refer to the explanation comment in the patch.

1 files changed, 8 insertions, 0 deletions

diff --git a/pkgs/development/compilers/ghc/9.2.5.nix b/pkgs/development/compilers/ghc/9.2.5.nix
index e7c75fcaccf94..b2046479ea8bd 100644
--- a/pkgs/development/compilers/ghc/9.2.5.nix
+++ b/pkgs/development/compilers/ghc/9.2.5.nix
@@ -203,6 +203,14 @@ stdenv.mkDerivation (rec {
       extraPrefix = "libraries/Cabal/";
       sha256 = "sha256-yRQ6YmMiwBwiYseC5BsrEtDgFbWvst+maGgDtdD0vAY=";
     })
+  ] ++ lib.optionals (stdenv.targetPlatform.isDarwin && stdenv.targetPlatform.isAarch64) [
+    # Prevent the paths module from emitting symbols that we don't use
+    # when building with separate outputs.
+    #
+    # These cause problems as they're not eliminated by GHC's dead code
+    # elimination on aarch64-darwin. (see
+    # https://github.com/NixOS/nixpkgs/issues/140774 for details).
+    ./Cabal-3.6-paths-fix-cycle-aarch64-darwin.patch
   ];
 
   postPatch = "patchShebangs .";