diff --git a/Language/Haskell/GhcMod/CaseSplit.hs b/Language/Haskell/GhcMod/CaseSplit.hs
index 77603ca..5d2c414 100644
--- a/Language/Haskell/GhcMod/CaseSplit.hs
+++ b/Language/Haskell/GhcMod/CaseSplit.hs
@@ -26,6 +26,7 @@ import Language.Haskell.GhcMod.SrcUtils
 import Language.Haskell.GhcMod.Doc
 import Language.Haskell.GhcMod.Logging
 import Language.Haskell.GhcMod.Types
+import Language.Haskell.GhcMod.FileMapping (fileModSummaryWithMapping)
 
 ----------------------------------------------------------------
 -- CASE SPLITTING
@@ -51,7 +52,7 @@ splits file lineNo colNo =
       crdl <- cradle
       style <- getStyle
       dflag <- G.getSessionDynFlags
-      modSum <- Gap.fileModSummary (cradleCurrentDir crdl </> file)
+      modSum <- fileModSummaryWithMapping (cradleCurrentDir crdl </> file)
       whenFound' opt (getSrcSpanTypeForSplit modSum lineNo colNo) $ \x -> case x of
         (SplitInfo varName bndLoc (varLoc,varT) _matches) -> do
           let varName' = showName dflag style varName  -- Convert name to string
diff --git a/Language/Haskell/GhcMod/FileMapping.hs b/Language/Haskell/GhcMod/FileMapping.hs
index bae425e..5d95868 100644
--- a/Language/Haskell/GhcMod/FileMapping.hs
+++ b/Language/Haskell/GhcMod/FileMapping.hs
@@ -3,6 +3,7 @@ module Language.Haskell.GhcMod.FileMapping
     , loadMappedFiles
     , unloadMappedFile
     , mapFile
+    , fileModSummaryWithMapping
     ) where
 
 import Language.Haskell.GhcMod.Types
@@ -48,3 +49,11 @@ mkMappedTarget tid taoc _ = return $ mkTarget tid taoc Nothing
 
 unloadMappedFile :: IOish m => FilePath -> GhcModT m ()
 unloadMappedFile = (delMMappedFile =<<) . getCanonicalFileNameSafe
+
+fileModSummaryWithMapping :: (IOish m, GmState m, GhcMonad m, GmEnv m) =>
+                            FilePath -> m ModSummary
+fileModSummaryWithMapping fn = do
+  mmf <- getCanonicalFileNameSafe fn >>= lookupMMappedFile
+  case mmf of
+    Just (RedirectedMapping to) -> fileModSummary to
+    _                           -> fileModSummary fn
diff --git a/Language/Haskell/GhcMod/FillSig.hs b/Language/Haskell/GhcMod/FillSig.hs
index 1f65f93..02da7a0 100644
--- a/Language/Haskell/GhcMod/FillSig.hs
+++ b/Language/Haskell/GhcMod/FillSig.hs
@@ -27,6 +27,7 @@ import Language.Haskell.GhcMod.Logging (gmLog)
 import Language.Haskell.GhcMod.Pretty (showDoc)
 import Language.Haskell.GhcMod.Doc
 import Language.Haskell.GhcMod.Types
+import Language.Haskell.GhcMod.FileMapping (fileModSummaryWithMapping)
 import Outputable (PprStyle)
 import qualified Type as Ty
 import qualified HsBinds as Ty
@@ -76,7 +77,7 @@ sig file lineNo colNo =
       opt <- options
       style <- getStyle
       dflag <- G.getSessionDynFlags
-      modSum <- Gap.fileModSummary file
+      modSum <- fileModSummaryWithMapping file
       whenFound opt (getSignature modSum lineNo colNo) $ \s ->
         case s of
           Signature loc names ty ->
@@ -345,7 +346,7 @@ refine file lineNo colNo (Expression expr) =
       opt <- options
       style <- getStyle
       dflag <- G.getSessionDynFlags
-      modSum <- Gap.fileModSummary file
+      modSum <- fileModSummaryWithMapping file
       p <- G.parseModule modSum
       tcm@TypecheckedModule{tm_typechecked_source = tcs} <- G.typecheckModule p
       ety <- G.exprType expr
@@ -422,7 +423,7 @@ auto file lineNo colNo =
         opt <- options
         style <- getStyle
         dflag <- G.getSessionDynFlags
-        modSum <- Gap.fileModSummary file
+        modSum <- fileModSummaryWithMapping file
         p <- G.parseModule modSum
         tcm@TypecheckedModule {
                  tm_typechecked_source = tcs
diff --git a/Language/Haskell/GhcMod/Info.hs b/Language/Haskell/GhcMod/Info.hs
index be32635..23e5950 100644
--- a/Language/Haskell/GhcMod/Info.hs
+++ b/Language/Haskell/GhcMod/Info.hs
@@ -22,6 +22,7 @@ import Language.Haskell.GhcMod.Logging
 import Language.Haskell.GhcMod.Monad
 import Language.Haskell.GhcMod.SrcUtils
 import Language.Haskell.GhcMod.Types
+import Language.Haskell.GhcMod.FileMapping (fileModSummaryWithMapping)
 
 ----------------------------------------------------------------
 
@@ -60,7 +61,7 @@ types file lineNo colNo =
     runGmlT' [Left file] deferErrors $
       withContext $ do
         crdl         <- cradle
-        modSum       <- Gap.fileModSummary (cradleCurrentDir crdl </> file)
+        modSum       <- fileModSummaryWithMapping (cradleCurrentDir crdl </> file)
         srcSpanTypes <- getSrcSpanType modSum lineNo colNo
         dflag        <- G.getSessionDynFlags
         st           <- getStyle