haskell.packages.ghc901.haskell-language-server: Fix build

pkgs/development/haskell-modules/configuration-ghc-9.0.x.nix

@@ -104,14 +104,80 @@ self: super: {
   # https://github.com/Soostone/retry/issues/71
   retry = dontCheck super.retry;
 
-  # hlint 3.3 needs a ghc-lib-parser newer than the one from stackage
-  hlint = super.hlint_3_3_4.overrideScope (self: super: {
-    ghc-lib-parser = overrideCabal self.ghc-lib-parser_9_0_1_20210324 {
-      doHaddock = false;
-    };
-    ghc-lib-parser-ex = self.ghc-lib-parser-ex_9_0_0_4;
-  });
+  # Hlint needs >= 3.3.4 for ghc 9 support.
+  hlint = super.hlint_3_3_4;
 
-  # pick right version for compiler
+  # 2021-09-18: ghc-api-compat and ghc-lib-* need >= 9.0.x versions for hls and hlint
   ghc-api-compat = doDistribute super.ghc-api-compat_9_0_1;
+  ghc-lib-parser = self.ghc-lib-parser_9_0_1_20210324;
+  ghc-lib-parser-ex = self.ghc-lib-parser-ex_9_0_0_4;
+  ghc-lib = self.ghc-lib_9_0_1_20210324;
+
+  # 2021-09-18: Need semialign >= 1.2 for correct bounds
+  semialign = super.semialign_1_2;
+
+  # Will probably be needed for brittany support
+  # https://github.com/lspitzner/czipwith/pull/2
+  #czipwith = appendPatch super.czipwith
+  #    (pkgs.fetchpatch {
+  #      url = "https://github.com/lspitzner/czipwith/commit/b6245884ae83e00dd2b5261762549b37390179f8.patch";
+  #      sha256 = "08rpppdldsdwzb09fmn0j55l23pwyls2dyzziw3yjc1cm0j5vic5";
+  #    });
+
+  # 2021-09-18: https://github.com/mokus0/th-extras/pull/8
+  # Release is missing, but asked for in the above PR.
+  th-extras = overrideCabal super.th-extras (old: {
+      version = assert old.version == "0.0.0.4"; "unstable-2021-09-18";
+      src = pkgs.fetchFromGitHub  {
+        owner = "mokus0";
+        repo = "th-extras";
+        rev = "0d050b24ec5ef37c825b6f28ebd46787191e2a2d";
+        sha256 = "045f36yagrigrggvyb96zqmw8y42qjsllhhx2h20q25sk5h44xsd";
+      };
+      libraryHaskellDepends = old.libraryHaskellDepends ++ [self.th-abstraction];
+    });
+
+  # 2021-09-18: GHC 9 compat release is missing
+  # Issue: https://github.com/obsidiansystems/dependent-sum/issues/65
+  dependent-sum-template = dontCheck (appendPatch super.dependent-sum-template
+      (pkgs.fetchpatch {
+        url = "https://github.com/obsidiansystems/dependent-sum/commit/8cf4c7fbc3bfa2be475a17bb7c94a1e1e9a830b5.patch";
+        sha256 = "02wyy0ciicq2x8lw4xxz3x5i4a550mxfidhm2ihh60ni6am498ff";
+        stripLen = 2;
+        extraPrefix = "";
+      }));
+
+  # 2021-09-18: cabal2nix does not detect the need for ghc-api-compat.
+  hiedb = overrideCabal super.hiedb (old: {
+    libraryHaskellDepends = old.libraryHaskellDepends ++ [self.ghc-api-compat];
+  });
+
+  # 2021-09-18: Need path >= 0.9.0 for ghc 9 compat
+  path = self.path_0_9_0;
+  # 2021-09-18: Need ormolu >= 0.3.0.0 for ghc 9 compat
+  ormolu = self.ormolu_0_3_0_0;
+  # 2021-09-18: https://github.com/haskell/haskell-language-server/issues/2206
+  # Restrictive upper bound on ormolu
+  hls-ormolu-plugin = doJailbreak super.hls-ormolu-plugin;
+
+  # 2021-09-18: The following plugins don‘t work yet on ghc9.
+  haskell-language-server = appendConfigureFlags (super.haskell-language-server.override {
+    hls-tactics-plugin = null; # No upstream support, generic-lens-core fail
+    hls-splice-plugin = null; # No upstream support in hls 1.4.0, should be fixed in 1.5
+    hls-refine-imports-plugin = null; # same issue es splice-plugin
+    hls-class-plugin = null; # No upstream support
+
+    hls-fourmolu-plugin = null; # No upstream support, needs new fourmolu release
+    hls-stylish-haskell-plugin = null; # No upstream support
+    hls-brittany-plugin = null; # No upstream support, needs new brittany release
+  }) [
+    "-f-tactic"
+    "-f-splice"
+    "-f-refineimports"
+    "-f-class"
+
+    "-f-fourmolu"
+    "-f-brittany"
+    "-f-stylishhaskell"
+  ];
 }

pkgs/development/tools/haskell/haskell-language-server/withWrapper.nix

@@ -1,4 +1,4 @@
-{ lib, supportedGhcVersions ? [ "884" "8107" ], stdenv, haskellPackages
+{ lib, supportedGhcVersions ? [ "884" "8107" "901" ], stdenv, haskellPackages
 , haskell }:
 #
 # The recommended way to override this package is

pkgs/top-level/release-haskell.nix

@@ -306,9 +306,7 @@ let
       Cabal_3_6_1_0 = with compilerNames; [ ghc884 ghc8107 ghc901 ghc921 ];
       cabal2nix-unstable = all;
       funcmp = all;
-      # Doesn't currently work on ghc-9.0:
-      # https://github.com/haskell/haskell-language-server/issues/297
-      haskell-language-server = with compilerNames; [ ghc884 ghc8107 ];
+      haskell-language-server = all;
       hoogle = all;
       hsdns = all;
       jailbreak-cabal = all;