Re-introduce call to makeDeltaAst to fix #4731

plugins/hls-class-plugin/src/Ide/Plugin/Class/ExactPrint.hs

@@ -24,7 +24,7 @@ makeEditText :: Monad m => ParsedModule -> DynFlags -> AddMinimalMethodsParams -
 makeEditText pm df AddMinimalMethodsParams{..} = do
     mDecls <- MaybeT . pure $ traverse (makeMethodDecl df) methodGroup
     let ps =
-#if !MIN_VERSION_ghc(9,9,0)
+#if !MIN_VERSION_ghc(9,10,0) || MIN_VERSION_ghc(9,10,1)
             makeDeltaAst $
 #endif
                 pm_parsed_source pm

plugins/hls-class-plugin/test/Main.hs

@@ -66,6 +66,12 @@ codeActionTests = testGroup
       getActionByTitle "Add placeholders for 'g','h'"
   , goldenWithClass "Creates a placeholder when all top-level decls are indented" "T7" "" $
       getActionByTitle "Add placeholders for 'g','h','i'"
+  , testGroup "with preprocessors"
+    [ knownBrokenInEnv [GhcVer GHC910]
+        "See issue https://github.com/haskell/haskell-language-server/issues/4731 for details." $
+        goldenWithClass "Creates a placeholder for '<>'" "T8" "diamond" $
+      getActionByTitle "Add placeholders for '<>'"
+      ]
   , goldenWithClass "Don't insert pragma with GHC2021" "InsertWithGHC2021Enabled" "" $
       getActionByTitle "Add placeholders for '==' with signature(s)"
   , goldenWithClass "Insert pragma if not exist" "InsertWithoutPragma" "" $

plugins/hls-class-plugin/test/testdata/T8.diamond.expected.hs

@@ -0,0 +1,6 @@
+data Set a = Set
+
+instance Semigroup (Set a) where
+  (<>) = _
+
+instance Monoid (Set a) where

plugins/hls-class-plugin/test/testdata/T8.hs

@@ -0,0 +1,5 @@
+data Set a = Set
+
+instance Semigroup (Set a) where
+
+instance Monoid (Set a) where