Fix hadrianEvalPackages

Author: hamishmack

build.nix

@@ -28,7 +28,9 @@ in rec {
       });
     } // pkgs.lib.optionalAttrs (__compareVersions haskell.compiler.${compiler-nix-name}.version "9.4" >= 0) {
       # Make sure the plan for hadrian is cached (we need it to instanciate ghc).
-      hadrian-plan = pkgs.haskell-nix.compiler.${compiler-nix-name}.hadrian.project.plan-nix;
+      hadrian-plan = (pkgs.haskell-nix.compiler.${compiler-nix-name}.hadrian.project.appendModule [{
+        compilerSelection = p: builtins.mapAttrs.override { hadiranEvalPackages = evalPackages; } p.haskell-nix.compiler;
+      }]).plan-nix;
       # Also include the same plan evaluated on the eval system (probably x86_64-linux).
       hadrian-plan-eval = (pkgs.haskell-nix.compiler.${compiler-nix-name}.override { hadrianEvalPackages = evalPackages; }).hadrian.project.plan-nix;
     } // pkgs.lib.optionalAttrs (__compareVersions haskell.compiler.${compiler-nix-name}.version "9.8" < 0) {

ci.nix

@@ -63,7 +63,7 @@
         ghc910 = true;
         ghc912 = true;
       } // nixpkgs.lib.optionalAttrs (nixpkgsName == "unstable") {
-        ghc96 = false;
+        ghc96 = true;
         ghc96X = true;
         ghc98 = true;
         ghc98llvm = false;

lib/call-cabal-project-to-nix.nix

@@ -13,7 +13,7 @@
 , cabalProjectLocal    ? null
 , cabalProjectFreeze   ? null
 , caller               ? "callCabalProjectToNix" # Name of the calling function for better warning messages
-, compilerSelection    ? p: p.haskell-nix.compiler
+, compilerSelection    ? p: builtins.mapAttrs (_: x: x.override { hadrianEvalPackages = evalPackages; }) p.haskell-nix.compiler
 , ghcOverride   ? null # Used when we need to set ghc explicitly during bootstrapping
 , configureArgs ? "" # Extra arguments to pass to `cabal v2-configure`.
                      # `--enable-tests --enable-benchmarks` are included by default.

modules/hackage.nix

@@ -98,12 +98,12 @@ in
     # this should allow us to use `config` overrides
     # in the nixpkgs setup, and properly override the
     # complier as needed.
-    default = pkgs.buildPackages.haskell-nix.compiler.${config.compiler.nix-name} or (throw ''
+    default = (pkgs.buildPackages.haskell-nix.compiler.${config.compiler.nix-name} or (throw ''
       This version of Nixpkgs does not contain GHC ${config.compiler.version}
       (or it is not present at attribute '${config.compiler.nix-name})').
       Either switch to a version of Nixpkgs which does have this version, or use a version
       of GHC which the current version of Nixpkgs contains.
-    '');
+    '')).override { hadrianEvalPackages = config.evalPackages; };
     defaultText = "pkgs.buildPackages.haskell-nix.compiler.\${config.compiler.nix-name}";
   };
 

overlays/haskell.nix

@@ -682,12 +682,14 @@ final: prev: {
                     ++ (config.modules or [])
                     ++ [ {
                       ghc.package =
-                        if config.ghcOverride != null
-                          then config.ghcOverride
-                        else if config.ghc != null
-                          then config.ghc
-                        else
-                          final.lib.mkDefault selectedCompiler;
+                        let ghc =
+                          if config.ghcOverride != null
+                            then config.ghcOverride
+                          else if config.ghc != null
+                            then config.ghc
+                          else
+                            final.lib.mkDefault selectedCompiler;
+                        in if ghc.isHaskellNixCompiler or false then ghc.override { hadrianEvalPackages = evalPackages; } else ghc;
                       compiler.nix-name = final.lib.mkForce config.compiler-nix-name;
                       evalPackages = final.lib.mkDefault evalPackages;
                     } ];
@@ -950,7 +952,7 @@ final: prev: {
                   modules = [ { _module.args.buildModules = final.lib.mkForce buildProject.pkg-set; }
                       (mkCacheModule cache) ]
                     ++ (config.modules or [])
-                    ++ final.lib.optional (config.ghc != null) { ghc.package = config.ghc; }
+                    ++ final.lib.optional (config.ghc != null) { ghc.package = config.ghc.override { hadrianEvalPackages = evalPackages; }; }
                     ++ final.lib.optional (config.compiler-nix-name != null)
                         { compiler.nix-name = final.lib.mkForce config.compiler-nix-name; }
                     ++ [ { evalPackages = final.lib.mkDefault evalPackages; } ];

test/supported-langauges/default.nix

@@ -1,7 +1,7 @@
 { stdenv, pkgs, lib, recurseIntoAttrs, testSrc, compiler-nix-name, evalPackages, buildPackages }:
 
 let
-  ghc = buildPackages.haskell-nix.compiler.${compiler-nix-name};
+  ghc = buildPackages.haskell-nix.compiler.${compiler-nix-name}.override { hadrianEvalPackages = evalPackages; };
 
   supported-langauges = import ../../lib/supported-languages.nix {
     inherit pkgs evalPackages ghc;