Push CPP statements to compatibility module

Author: fendor

ghcide/src/Development/IDE/Core/Compile.hs

@@ -1075,11 +1075,7 @@ parseHeader dflags filename contents = do
    let loc  = mkRealSrcLoc (Util.mkFastString filename) 1 1
    case unP Compat.parseHeader (initParserState (initParserOpts dflags) contents loc) of
      PFailedWithErrorMessages msgs ->
-#if MIN_VERSION_ghc(9,5,0)
-        throwE $ diagFromErrMsgs sourceParser dflags $ msgs dflags
-#else
-        throwE $ diagFromSDocErrMsgs sourceParser dflags $ msgs dflags
-#endif
+        throwE $ diagFromGhcErrorMessages sourceParser dflags $ msgs dflags
      POk pst rdr_module -> do
         let (warns, errs) = renderMessages $ getPsMessages pst
 
@@ -1093,17 +1089,9 @@ parseHeader dflags filename contents = do
         -- errors are those from which a parse tree just can't
         -- be produced.
         unless (null errs) $
-#if MIN_VERSION_ghc(9,5,0)
-            throwE $ diagFromErrMsgs sourceParser dflags errs
-#else
-            throwE $ diagFromSDocErrMsgs sourceParser dflags errs
-#endif
+            throwE $ diagFromGhcErrorMessages sourceParser dflags errs
 
-#if MIN_VERSION_ghc(9,5,0)
-        let warnings = diagFromErrMsgs sourceParser dflags warns
-#else
-        let warnings = diagFromSDocErrMsgs sourceParser dflags warns
-#endif
+        let warnings = diagFromGhcErrorMessages sourceParser dflags warns
         return (warnings, rdr_module)
 
 -- | Given a buffer, flags, and file path, produce a
@@ -1121,11 +1109,7 @@ parseFileContents env customPreprocessor filename ms = do
        contents = fromJust $ ms_hspp_buf ms
    case unP Compat.parseModule (initParserState (initParserOpts dflags) contents loc) of
      PFailedWithErrorMessages msgs ->
-#if MIN_VERSION_ghc(9,5,0)
-       throwE $ diagFromErrMsgs sourceParser dflags $ msgs dflags
-#else
-       throwE $ diagFromSDocErrMsgs sourceParser dflags $ msgs dflags
-#endif
+       throwE $ diagFromGhcErrorMessages sourceParser dflags $ msgs dflags
      POk pst rdr_module ->
          let
              psMessages = getPsMessages pst
@@ -1159,12 +1143,7 @@ parseFileContents env customPreprocessor filename ms = do
                -- errors are those from which a parse tree just can't
                -- be produced.
                unless (null errors) $
-#if MIN_VERSION_ghc(9,5,0)
-                 throwE $ diagFromErrMsgs sourceParser dflags errors
-#else
-                 throwE $ diagFromSDocErrMsgs sourceParser dflags errors
-#endif
-
+                 throwE $ diagFromGhcErrorMessages sourceParser dflags errors
 
                -- To get the list of extra source files, we take the list
                -- that the parser gave us,
@@ -1194,11 +1173,7 @@ parseFileContents env customPreprocessor filename ms = do
                srcs2 <- liftIO $ filterM doesFileExist srcs1
 
                let pm = ParsedModule ms parsed' srcs2
-#if MIN_VERSION_ghc(9,5,0)
-                   warnings = diagFromErrMsgs sourceParser dflags warns
-#else
-                   warnings = diagFromSDocErrMsgs sourceParser dflags warns
-#endif
+                   warnings = diagFromGhcErrorMessages sourceParser dflags warns
                pure (warnings ++ preproc_warning_file_diagnostics, pm)
 
 loadHieFile :: Compat.NameCacheUpdater -> FilePath -> IO GHC.HieFile

ghcide/src/Development/IDE/GHC/Error.hs

@@ -5,7 +5,8 @@
 module Development.IDE.GHC.Error
   (
     -- * Producing Diagnostic values
-    diagFromErrMsgs
+    diagFromGhcErrorMessages
+  , diagFromErrMsgs
   , diagFromErrMsg
   , diagFromSDocErrMsgs
   , diagFromSDocErrMsg
@@ -72,6 +73,21 @@ diagFromErrMsg diagSource dflags origErr =
     in
     diagFromSDocWithOptionalOrigMsg diagSource dflags err
 
+-- | Compatibility function for creating '[FileDiagnostic]' from
+-- a 'Compat.Bag' of GHC error messages.
+-- The function signature changes based on the GHC version.
+-- While this is not desirable, it avoids more CPP statements in code
+-- that implements actual logic.
+#if MIN_VERSION_ghc(9,5,0)
+diagFromGhcErrorMessages :: T.Text -> DynFlags -> Compat.Bag (MsgEnvelope GhcMessage) -> [FileDiagnostic]
+diagFromGhcErrorMessages sourceParser dflags errs =
+    diagFromErrMsgs sourceParser dflags errs
+#else
+diagFromGhcErrorMessages :: T.Text -> DynFlags -> Compat.Bag (MsgEnvelope Compat.DecoratedSDoc) -> [FileDiagnostic]
+diagFromGhcErrorMessages sourceParser dflags errs =
+    diagFromSDocErrMsgs sourceParser dflags errs
+#endif
+
 diagFromErrMsgs :: T.Text -> DynFlags -> Compat.Bag (MsgEnvelope GhcMessage) -> [FileDiagnostic]
 diagFromErrMsgs diagSource dflags = concatMap (diagFromErrMsg diagSource dflags) . Compat.bagToList