diff --git a/ghcide.cabal b/ghcide.cabal
--- a/ghcide.cabal
+++ b/ghcide.cabal
@@ -2,7 +2,7 @@
 build-type:         Simple
 category:           Development
 name:               ghcide
-version:            1.4.0.1
+version:            1.4.0.2
 license:            Apache-2.0
 license-file:       LICENSE
 author:             Digital Asset and Ghcide contributors
@@ -13,7 +13,7 @@
     A library for building Haskell IDE's on top of the GHC API.
 homepage:           https://github.com/haskell/haskell-language-server/tree/master/ghcide#readme
 bug-reports:        https://github.com/haskell/haskell-language-server/issues
-tested-with:        GHC == 8.6.4 || == 8.6.5 || == 8.8.2 || == 8.8.3 || == 8.8.4 || == 8.10.2 || == 8.10.3 || == 8.10.4 || == 8.10.5 || == 9.0.1
+tested-with:        GHC == 8.6.4 || == 8.6.5 || == 8.8.3 || == 8.8.4 || == 8.10.2 || == 8.10.3 || == 8.10.4 || == 8.10.5 || == 9.0.1
 extra-source-files: README.md CHANGELOG.md
                     test/data/**/*.project
                     test/data/**/*.cabal
diff --git a/src/Development/IDE/Core/Compile.hs b/src/Development/IDE/Core/Compile.hs
--- a/src/Development/IDE/Core/Compile.hs
+++ b/src/Development/IDE/Core/Compile.hs
@@ -528,13 +528,15 @@
 -- can just increment the 'indexCompleted' TVar and exit.
 --
 indexHieFile :: ShakeExtras -> ModSummary -> NormalizedFilePath -> Fingerprint -> Compat.HieFile -> IO ()
-indexHieFile se mod_summary srcPath hash hf = do
+indexHieFile se mod_summary srcPath !hash hf = do
  IdeOptions{optProgressStyle} <- getIdeOptionsIO se
  atomically $ do
   pending <- readTVar indexPending
   case HashMap.lookup srcPath pending of
     Just pendingHash | pendingHash == hash -> pure () -- An index is already scheduled
     _ -> do
+      -- hiedb doesn't use the Haskell src, so we clear it to avoid unnecessarily keeping it around
+      let !hf' = hf{hie_hs_src = mempty}
       modifyTVar' indexPending $ HashMap.insert srcPath hash
       writeTQueue indexQueue $ \db -> do
         -- We are now in the worker thread
@@ -547,7 +549,7 @@
             Just pendingHash -> pendingHash /= hash
         unless newerScheduled $ do
           pre optProgressStyle
-          addRefsFromLoaded db targetPath (RealFile $ fromNormalizedFilePath srcPath) hash hf
+          addRefsFromLoaded db targetPath (RealFile $ fromNormalizedFilePath srcPath) hash hf'
           post
   where
     mod_location    = ms_location mod_summary