[feat] update for compatibility with ghc 9.8

.envrc

@@ -1 +1 @@
-use flake -Lv 
+use flake .#ghc98 -Lv 

.github/workflows/test-flake.yml

@@ -12,6 +12,7 @@ jobs:
       with:
         github_access_token: ${{ secrets.GITHUB_TOKEN }}
     - run: nix flake check -Lv --allow-import-from-derivation --fallback --accept-flake-config
-    - run: nix build .#transitive-anns -Lv --fallback --accept-flake-config
+    - run: nix build .#ghc96-transitive-anns -Lv --fallback --accept-flake-config
+    - run: nix build .#ghc98-transitive-anns -Lv --fallback --accept-flake-config
     - run: nix build .#ghc94-transitive-anns -Lv --fallback --accept-flake-config
     - run: nix build .#ghc92-transitive-anns -Lv --fallback --accept-flake-config

flake.nix

@@ -31,22 +31,19 @@
         };
 
         haskellProjects.ghc92 = {
-          packages = {};
-          settings = {};
           basePackages = pkgs.haskell.packages.ghc92;
           devShell.mkShellArgs.shellHook = config.pre-commit.installationScript;
         };
-
         haskellProjects.ghc94 = {
-          packages = {};
-          settings = {};
           basePackages = pkgs.haskell.packages.ghc94;
           devShell.mkShellArgs.shellHook = config.pre-commit.installationScript;
         };
-        haskellProjects.default = {
-          packages = {};
-          settings = {};
-          basePackages = pkgs.haskellPackages;
+        haskellProjects.ghc96 = {
+          basePackages = pkgs.haskell.packages.ghc96;
+          devShell.mkShellArgs.shellHook = config.pre-commit.installationScript;
+        };
+        haskellProjects.ghc98 = {
+          basePackages = pkgs.haskell.packages.ghc98;
           devShell.mkShellArgs.shellHook = config.pre-commit.installationScript;
         };
       };

src/TransitiveAnns/Plugin.hs

@@ -93,7 +93,11 @@ transitiveAnnEnv annenv binds =
 -- | Determine if the given constraint is of the given class.
 findWanted :: Class -> Ct -> Maybe Ct
 findWanted c ct = do
+#if MIN_VERSION_GLASGOW_HASKELL(9,8,0,0)
+  let p = ctev_pred $ ctEvidence ct
+#else 
   let p = ctev_pred $ cc_ev ct
+#endif
   splitTyConApp_maybe p >>= \(x, _) ->
      if x == classTyCon c then Just ct else Nothing
 
@@ -213,7 +217,11 @@ solveKnownAnns tad known = do
 -- that we will install during the core plugin.
 solveAddAnn :: TransitiveAnnsData -> Ct -> TcPluginM [(EvTerm, Ct)]
 solveAddAnn tad to_add
+#if MIN_VERSION_GLASGOW_HASKELL(9,8,0,0)
+  | Just ann <- parsePromotedAnn tad $ ctev_pred $ ctEvidence to_add
+#else
   | Just ann <- parsePromotedAnn tad $ ctev_pred $ cc_ev to_add
+#endif
   = do
     decs <- unsafeTcPluginTcM $ tcg_binds <$> getGblEnv
     Just dec <- pure $ fmap fst $ getDec decs $ location to_add