Fix haskell#723

Author: simmsb

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

@@ -184,17 +184,26 @@ mkHiFileResultCompile
 mkHiFileResultCompile session' tcm simplified_guts ltype = catchErrs $ do
   let session = session' { hsc_dflags = ms_hspp_opts ms }
       ms = pm_mod_summary $ tmrParsed tcm
+      tcGblEnv = tmrTypechecked tcm
   -- give variables unique OccNames
-  (guts, details) <- tidyProgram session simplified_guts
-
   let genLinkable = case ltype of
         ObjectLinkable -> generateObjectCode
         BCOLinkable -> generateByteCode
 
-  (diags, linkable) <- genLinkable session ms guts
 #if MIN_GHC_API_VERSION(8,10,0)
-  let !partial_iface = force (mkPartialIface session details simplified_guts)
-  final_iface <- mkFullIface session partial_iface
+  (final_iface, linkable, details, diags) <-
+    if mg_hsc_src simplified_guts == HsBootFile
+    then do
+        sf <- finalSafeMode (ms_hspp_opts ms) tcGblEnv
+        details <- mkBootModDetailsTc session tcGblEnv
+        r <- mkIfaceTc session sf details tcGblEnv
+        pure (r, Nothing, details, [])
+    else do
+        (guts, details) <- tidyProgram session simplified_guts
+        (diags, linkable) <- genLinkable session ms guts
+        let !partial_iface = force (mkPartialIface session details simplified_guts)
+        r <- mkFullIface session partial_iface
+        pure (r, linkable, details, diags)
 #else
   (final_iface,_) <- mkIface session Nothing details simplified_guts
 #endif