From cba7eafc011616e072774b26905b8f31bb5046b6 Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyich@gmail.com>
Date: Tue, 2 Jan 2024 20:39:23 +0000
Subject: [PATCH] haskell.compiler.ghcjs: expose `llvmPackages` attribute via
 passthru

Files like `pkgs/development/haskell-modules/configuration-ghc-8.10.x.nix`
assume `ghc` always has an `llvmPackages` attribue. Let's expose `null`
value from `ghcjs` to allow it's propagation.

This fixes package evaluation for `ghcjs` packages.
---
 pkgs/development/compilers/ghcjs/8.10/default.nix           | 1 +
 .../haskell-modules/configuration-ghc-8.10.x.nix            | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/compilers/ghcjs/8.10/default.nix b/pkgs/development/compilers/ghcjs/8.10/default.nix
index 78d757efee3c..4363dc32c21e 100644
--- a/pkgs/development/compilers/ghcjs/8.10/default.nix
+++ b/pkgs/development/compilers/ghcjs/8.10/default.nix
@@ -47,6 +47,7 @@ let
     inherit (bootGhcjs) version;
     isGhcjs = true;
 
+    llvmPackages = null;
     enableShared = true;
 
     socket-io = pkgsHostHost.nodePackages."socket.io";
diff --git a/pkgs/development/haskell-modules/configuration-ghc-8.10.x.nix b/pkgs/development/haskell-modules/configuration-ghc-8.10.x.nix
index 481db0d258fb..c335fdaacbcf 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-8.10.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-8.10.x.nix
@@ -8,7 +8,11 @@ in
 
 self: super: {
 
-  llvmPackages = pkgs.lib.dontRecurseIntoAttrs self.ghc.llvmPackages;
+  # ghcjs does not use `llvmPackages` and exposes `null` attribute.
+  llvmPackages =
+    if self.ghc.llvmPackages != null
+    then pkgs.lib.dontRecurseIntoAttrs self.ghc.llvmPackages
+    else null;
 
   # Disable GHC 8.10.x core libraries.
   array = null;