Avoid removing attrs of hpkgs

configuration-ghc-901.nix

@@ -2,16 +2,16 @@
 { pkgs }:
 
 let
-  removePluginPackages = hpkgs:
-    removeAttrs hpkgs [
-      "hls-tactics-plugin"
-      "hls-brittany-plugin"
-      "hls-stylish-haskell-plugin"
-      "hls-fourmolu-plugin"
-      "hls-splice-plugin"
-      "hls-ormolu-plugin"
-      "hls-eval-plugin"
-    ];
+  disabledPlugins = [
+    "hls-tactics-plugin"
+    "hls-brittany-plugin"
+    "hls-stylish-haskell-plugin"
+    "hls-fourmolu-plugin"
+    "hls-splice-plugin"
+    "hls-ormolu-plugin"
+    "hls-eval-plugin"
+  ];
+
   hpkgsOverride = hself: hsuper:
     with pkgs.haskell.lib;
     let
@@ -98,4 +98,7 @@ let
           "-f-tactic"
         ]) { };
     };
-in { tweakHpkgs = hpkgs: removePluginPackages (hpkgs.extend hpkgsOverride); }
+in {
+  inherit disabledPlugins;
+  tweakHpkgs = hpkgs: hpkgs.extend hpkgsOverride;
+}

flake.nix

@@ -175,13 +175,12 @@
           hpkgs.shellFor {
             doBenchmark = true;
             packages = p:
-              with lib;
-              # we can remove sources attrs from hpkgs to exclude HLS plugins,
-              # so hpkgs may not be the superset of hlsSources
-              pipe (attrNames hlsSources) [
-                (xs: map (name: if hpkgs ? name then p.${name} else null) xs)
-                (xs: remove null xs)
-              ];
+              with builtins;
+              map (name: p.${name}) (attrNames
+                (if hpkgs.ghc.version == "9.0.1" then
+                  removeAttrs hlsSources ghc901Config.disabledPlugins
+                else
+                  hlsSources));
             buildInputs = [ gmp zlib ncurses capstone tracy (gen-hls-changelogs hpkgs) ]
               ++ (with hpkgs; [
                 cabal-install