EPA: Make EOF position part of AnnsModule

Closes #20951
Closes #19697

25 files changed, 190 insertions, 209 deletions

diff --git a/compiler/GHC/Hs.hs b/compiler/GHC/Hs.hs
index c327ff1fd4..eb66dc0f28 100644
--- a/compiler/GHC/Hs.hs
+++ b/compiler/GHC/Hs.hs
@@ -101,7 +101,8 @@ deriving instance Data (HsModule GhcPs)
 data AnnsModule
   = AnnsModule {
     am_main :: [AddEpAnn],
-    am_decls :: AnnList
+    am_decls :: AnnList,
+    am_eof :: Maybe (RealSrcSpan, RealSrcSpan) -- End of file and end of prior token
     } deriving (Data, Eq)
 
 instance Outputable (HsModule GhcPs) where
diff --git a/compiler/GHC/Parser.y b/compiler/GHC/Parser.y
index cebeba3809..a64ee3f07e 100644
--- a/compiler/GHC/Parser.y
+++ b/compiler/GHC/Parser.y
@@ -886,7 +886,7 @@ signature :: { Located (HsModule GhcPs) }
        : 'signature' modid maybemodwarning maybeexports 'where' body
              {% fileSrcSpan >>= \ loc ->
                 acs (\cs-> (L loc (HsModule (XModulePs
-                                               (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnSignature $1, mj AnnWhere $5] (fstOf3 $6)) cs)
+                                               (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnSignature $1, mj AnnWhere $5] (fstOf3 $6) Nothing) cs)
                                                (thdOf3 $6) $3 Nothing)
                                             (Just $2) $4 (fst $ sndOf3 $6)
                                             (snd $ sndOf3 $6)))
@@ -895,16 +895,16 @@ signature :: { Located (HsModule GhcPs) }
 module :: { Located (HsModule GhcPs) }
        : 'module' modid maybemodwarning maybeexports 'where' body
              {% fileSrcSpan >>= \ loc ->
-                acsFinal (\cs -> (L loc (HsModule (XModulePs
-                                                     (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnModule $1, mj AnnWhere $5] (fstOf3 $6)) cs)
+                acsFinal (\cs eof -> (L loc (HsModule (XModulePs
+                                                     (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnModule $1, mj AnnWhere $5] (fstOf3 $6) eof) cs)
                                                      (thdOf3 $6) $3 Nothing)
                                                   (Just $2) $4 (fst $ sndOf3 $6)
                                                   (snd $ sndOf3 $6))
                     )) }
         | body2
                 {% fileSrcSpan >>= \ loc ->
-                   acsFinal (\cs -> (L loc (HsModule (XModulePs
-                                                        (EpAnn (spanAsAnchor loc) (AnnsModule [] (fstOf3 $1)) cs)
+                   acsFinal (\cs eof -> (L loc (HsModule (XModulePs
+                                                        (EpAnn (spanAsAnchor loc) (AnnsModule [] (fstOf3 $1) eof) cs)
                                                         (thdOf3 $1) Nothing Nothing)
                                                      Nothing Nothing
                                                      (fst $ sndOf3 $1) (snd $ sndOf3 $1)))) }
@@ -956,14 +956,14 @@ header  :: { Located (HsModule GhcPs) }
         : 'module' modid maybemodwarning maybeexports 'where' header_body
                 {% fileSrcSpan >>= \ loc ->
                    acs (\cs -> (L loc (HsModule (XModulePs
-                                                   (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnModule $1,mj AnnWhere $5] (AnnList Nothing Nothing Nothing [] [])) cs)
+                                                   (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnModule $1,mj AnnWhere $5] (AnnList Nothing Nothing Nothing [] []) Nothing) cs)
                                                    NoLayoutInfo $3 Nothing)
                                                 (Just $2) $4 $6 []
                           ))) }
         | 'signature' modid maybemodwarning maybeexports 'where' header_body
                 {% fileSrcSpan >>= \ loc ->
                    acs (\cs -> (L loc (HsModule (XModulePs
-                                                   (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnModule $1,mj AnnWhere $5] (AnnList Nothing Nothing Nothing [] [])) cs)
+                                                   (EpAnn (spanAsAnchor loc) (AnnsModule [mj AnnModule $1,mj AnnWhere $5] (AnnList Nothing Nothing Nothing [] []) Nothing) cs)
                                                    NoLayoutInfo $3 Nothing)
                                                 (Just $2) $4 $6 []
                           ))) }
@@ -4277,17 +4277,17 @@ acs a = do
   return (a cs)
 
 -- Called at the very end to pick up the EOF position, as well as any comments not allocated yet.
-acsFinal :: (EpAnnComments -> Located a) -> P (Located a)
+acsFinal :: (EpAnnComments -> Maybe (RealSrcSpan, RealSrcSpan) -> Located a) -> P (Located a)
 acsFinal a = do
-  let (L l _) = a emptyComments
+  let (L l _) = a emptyComments Nothing
   cs <- getCommentsFor l
   csf <- getFinalCommentsFor l
   meof <- getEofPos
   let ce = case meof of
-             Strict.Nothing  -> EpaComments []
-             Strict.Just (pos `Strict.And` gap) ->
-               EpaCommentsBalanced [] [L (realSpanAsAnchor pos) (EpaComment EpaEofComment gap)]
-  return (a (cs Semi.<> csf Semi.<> ce))
+             Strict.Nothing  -> Nothing
+             Strict.Just (pos `Strict.And` gap) -> Just (pos,gap)
+  return (a (cs Semi.<> csf) ce)
+
 
 acsa :: MonadP m => (EpAnnComments -> LocatedAn t a) -> m (LocatedAn t a)
 acsa a = do
diff --git a/compiler/GHC/Parser/Lexer.x b/compiler/GHC/Parser/Lexer.x
index dfccebce86..0f0f37075f 100644
--- a/compiler/GHC/Parser/Lexer.x
+++ b/compiler/GHC/Parser/Lexer.x
@@ -916,18 +916,11 @@ instance Outputable Token where
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 When using the Api Annotations to exact print a modified AST, managing
 the space before a comment is important.  The PsSpan in the comment
-token allows this to happen.
-
-We also need to track the space before the end of file. The normal
-mechanism of using the previous token does not work, as the ITeof is
-synthesised to come at the same location of the last token, and the
-normal previous token updating has by then updated the required
-location.
-
-We track this using a 2-back location, prev_loc2. This adds extra
-processing to every single token, which is a performance hit for
-something needed only at the end of the file. This needs
-improving. Perhaps a backward scan on eof?
+token allows this to happen, and this location is tracked in prev_loc
+in PState.  This only tracks physical tokens, so is not updated for
+zero-width ones.
+
+We also use this to track the space before the end-of-file marker.
 -}
 
 {- Note [Minus tokens]
@@ -1363,7 +1356,7 @@ lineCommentToken :: Action
 lineCommentToken span buf len buf2 = do
   b <- getBit RawTokenStreamBit
   if b then do
-         lt <- getLastLocComment
+         lt <- getLastLocIncludingComments
          strtoken (\s -> ITlineComment s lt) span buf len buf2
        else lexToken
 
@@ -1374,7 +1367,7 @@ lineCommentToken span buf len buf2 = do
 -}
 nested_comment :: Action
 nested_comment span buf len _buf2 = {-# SCC "nested_comment" #-} do
-  l <- getLastLocComment
+  l <- getLastLocIncludingComments
   let endComment input (L _ comment) = commentEnd lexToken input (Nothing, ITblockComment comment l) buf span
   input <- getInput
   -- Include decorator in comment
@@ -1478,7 +1471,7 @@ withLexedDocType :: (AlexInput -> ((HsDocStringDecorator -> HsDocString) -> (Hdk
                  -> P (PsLocated Token)
 withLexedDocType lexDocComment = do
   input@(AI _ buf) <- getInput
-  l <- getLastLocComment
+  l <- getLastLocIncludingComments
   case prevChar buf ' ' of
     -- The `Bool` argument to lexDocComment signals whether or not the next
     -- line of input might also belong to this doc comment.
@@ -2001,7 +1994,7 @@ lex_string_prag_comment :: (String -> PsSpan -> Token) -> Action
 lex_string_prag_comment mkTok span _buf _len _buf2
     = do input <- getInput
          start <- getParsedLoc
-         l <- getLastLocComment
+         l <- getLastLocIncludingComments
          tok <- go l [] input
          end <- getParsedLoc
          return (L (mkPsSpan start end) tok)
@@ -2494,9 +2487,7 @@ data PState = PState {
         tab_first  :: Strict.Maybe RealSrcSpan, -- pos of first tab warning in the file
         tab_count  :: !Word,             -- number of tab warnings in the file
         last_tk    :: Strict.Maybe (PsLocated Token), -- last non-comment token
-        prev_loc   :: PsSpan,      -- pos of previous token, including comments,
-        prev_loc2  :: PsSpan,      -- pos of two back token, including comments,
-                                   -- see Note [PsSpan in Comments]
+        prev_loc   :: PsSpan,      -- pos of previous non-virtual token, including comments,
         last_loc   :: PsSpan,      -- pos of current token
         last_len   :: !Int,        -- len of current token
         loc        :: PsLoc,       -- current loc (end of prev token + 1)
@@ -2624,24 +2615,21 @@ setLastToken loc len = P $ \s -> POk s {
   } ()
 
 setLastTk :: PsLocated Token -> P ()
-setLastTk tk@(L l _) = P $ \s -> POk s { last_tk = Strict.Just tk
-                                       , prev_loc = l
-                                       , prev_loc2 = prev_loc s} ()
+setLastTk tk@(L l _) = P $ \s ->
+  if isPointRealSpan (psRealSpan l)
+    then POk s { last_tk = Strict.Just tk } ()
+    else POk s { last_tk = Strict.Just tk
+               , prev_loc = l } ()
 
 setLastComment :: PsLocated Token -> P ()
-setLastComment (L l _) = P $ \s -> POk s { prev_loc = l
-                                         , prev_loc2 = prev_loc s} ()
+setLastComment (L l _) = P $ \s -> POk s { prev_loc = l } ()
 
 getLastTk :: P (Strict.Maybe (PsLocated Token))
 getLastTk = P $ \s@(PState { last_tk = last_tk }) -> POk s last_tk
 
 -- see Note [PsSpan in Comments]
-getLastLocComment :: P PsSpan
-getLastLocComment = P $ \s@(PState { prev_loc = prev_loc }) -> POk s prev_loc
-
--- see Note [PsSpan in Comments]
-getLastLocEof :: P PsSpan
-getLastLocEof = P $ \s@(PState { prev_loc2 = prev_loc2 }) -> POk s prev_loc2
+getLastLocIncludingComments :: P PsSpan
+getLastLocIncludingComments = P $ \s@(PState { prev_loc = prev_loc }) -> POk s prev_loc
 
 getLastLoc :: P PsSpan
 getLastLoc = P $ \s@(PState { last_loc = last_loc }) -> POk s last_loc
@@ -3024,7 +3012,6 @@ initParserState options buf loc =
       tab_count     = 0,
       last_tk       = Strict.Nothing,
       prev_loc      = mkPsSpan init_loc init_loc,
-      prev_loc2     = mkPsSpan init_loc init_loc,
       last_loc      = mkPsSpan init_loc init_loc,
       last_len      = 0,
       loc           = init_loc,
@@ -3498,8 +3485,8 @@ lexToken = do
   case alexScanUser exts inp sc of
     AlexEOF -> do
         let span = mkPsSpan loc1 loc1
-        lt <- getLastLocEof
-        setEofPos (psRealSpan span) (psRealSpan lt)
+        lc <- getLastLocIncludingComments
+        setEofPos (psRealSpan span) (psRealSpan lc)
         setLastToken span 0
         return (L span ITeof)
     AlexError (AI loc2 buf) ->
diff --git a/compiler/GHC/Types/SrcLoc.hs b/compiler/GHC/Types/SrcLoc.hs
index e783e90dd1..30ff00deed 100644
--- a/compiler/GHC/Types/SrcLoc.hs
+++ b/compiler/GHC/Types/SrcLoc.hs
@@ -64,6 +64,9 @@ module GHC.Types.SrcLoc (
         isGoodSrcSpan, isOneLineSpan, isZeroWidthSpan,
         containsSpan, isNoSrcSpan,
 
+        -- ** Predicates on RealSrcSpan
+        isPointRealSpan,
+
         -- * StringBuffer locations
         BufPos(..),
         getBufPos,
diff --git a/testsuite/tests/ghc-api/exactprint/LocalDecls2.expected.hs b/testsuite/tests/ghc-api/exactprint/LocalDecls2.expected.hs
index d2353e94c5..f015e958e9 100644
--- a/testsuite/tests/ghc-api/exactprint/LocalDecls2.expected.hs
+++ b/testsuite/tests/ghc-api/exactprint/LocalDecls2.expected.hs
@@ -4,5 +4,3 @@ foo a = bar a
   where
     nn :: Int
     nn = 2
-
-
diff --git a/testsuite/tests/ghc-api/exactprint/Test20239.stderr b/testsuite/tests/ghc-api/exactprint/Test20239.stderr
index bcbb818b05..8bfb5085ce 100644
--- a/testsuite/tests/ghc-api/exactprint/Test20239.stderr
+++ b/testsuite/tests/ghc-api/exactprint/Test20239.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { Test20239.hs:8:1 }
+       { Test20239.hs:7:34-63 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { Test20239.hs:8:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { Test20239.hs:7:34-63 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr
index 212f3f9bec..484a56ecc0 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T17544.hs:57:1 }
+       { T17544.hs:55:18-20 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { T17544.hs:57:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T17544.hs:57:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr
index 28f3f4ef63..1efed5e02e 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T17544_kw.hs:25:1 }
+       { T17544_kw.hs:24:18 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { T17544_kw.hs:25:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T17544_kw.hs:25:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/module/mod185.stderr b/testsuite/tests/module/mod185.stderr
index f5dbe2fa70..b9e5ee7849 100644
--- a/testsuite/tests/module/mod185.stderr
+++ b/testsuite/tests/module/mod185.stderr
@@ -16,16 +16,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { mod185.hs:6:1 }
+       { mod185.hs:5:8-24 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { mod185.hs:6:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { mod185.hs:6:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/DumpParsedAst.stderr b/testsuite/tests/parser/should_compile/DumpParsedAst.stderr
index fdea6a5bce..1e48180185 100644
--- a/testsuite/tests/parser/should_compile/DumpParsedAst.stderr
+++ b/testsuite/tests/parser/should_compile/DumpParsedAst.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { DumpParsedAst.hs:25:1 }
+       { DumpParsedAst.hs:24:17-23 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { DumpParsedAst.hs:25:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { DumpParsedAst.hs:25:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr b/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr
index 0f451eeb14..6050639d73 100644
--- a/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr
+++ b/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr
@@ -18,7 +18,11 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { DumpParsedAstComments.hs:17:1 }
+       { DumpParsedAstComments.hs:16:17-23 })))
     (EpaCommentsBalanced
      [(L
        (Anchor
@@ -44,13 +48,7 @@
         (EpaLineComment
          "-- Other comment")
         { DumpParsedAstComments.hs:5:30-34 }))]
-     [(L
-       (Anchor
-        { DumpParsedAstComments.hs:17:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { DumpParsedAstComments.hs:17:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/DumpSemis.stderr b/testsuite/tests/parser/should_compile/DumpSemis.stderr
index faa926b6c4..4e283a73fe 100644
--- a/testsuite/tests/parser/should_compile/DumpSemis.stderr
+++ b/testsuite/tests/parser/should_compile/DumpSemis.stderr
@@ -28,16 +28,14 @@
       ,(AddSemiAnn
         (EpaSpan { DumpSemis.hs:4:7 }))
       ,(AddSemiAnn
-        (EpaSpan { DumpSemis.hs:4:8 }))]))
+        (EpaSpan { DumpSemis.hs:4:8 }))])
+     (Just
+      ((,)
+       { DumpSemis.hs:46:1 }
+       { DumpSemis.hs:45:1 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { DumpSemis.hs:46:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { DumpSemis.hs:46:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/KindSigs.stderr b/testsuite/tests/parser/should_compile/KindSigs.stderr
index f9b9a986e4..df228cb912 100644
--- a/testsuite/tests/parser/should_compile/KindSigs.stderr
+++ b/testsuite/tests/parser/should_compile/KindSigs.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { KindSigs.hs:36:1 }
+       { KindSigs.hs:35:8-11 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { KindSigs.hs:36:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { KindSigs.hs:36:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/T15323.stderr b/testsuite/tests/parser/should_compile/T15323.stderr
index 36768671e4..a3bc49d34f 100644
--- a/testsuite/tests/parser/should_compile/T15323.stderr
+++ b/testsuite/tests/parser/should_compile/T15323.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T15323.hs:7:1 }
+       { T15323.hs:6:54 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { T15323.hs:7:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T15323.hs:7:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/T20452.stderr b/testsuite/tests/parser/should_compile/T20452.stderr
index 0c2982dd9c..f05cef65b8 100644
--- a/testsuite/tests/parser/should_compile/T20452.stderr
+++ b/testsuite/tests/parser/should_compile/T20452.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T20452.hs:10:1 }
+       { T20452.hs:9:85 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { T20452.hs:10:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T20452.hs:10:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/T20718.stderr b/testsuite/tests/parser/should_compile/T20718.stderr
index ab90eb29bc..bd071a0227 100644
--- a/testsuite/tests/parser/should_compile/T20718.stderr
+++ b/testsuite/tests/parser/should_compile/T20718.stderr
@@ -17,7 +17,11 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T20718.hs:12:1 }
+       { T20718.hs:11:1-8 })))
     (EpaCommentsBalanced
      [(L
        (Anchor
@@ -51,13 +55,7 @@
         (EpaLineComment
          "-- before 2")
         { T20718.hs:5:1-11 }))]
-     [(L
-       (Anchor
-        { T20718.hs:12:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T20718.hs:11:1-8 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/T20718b.stderr b/testsuite/tests/parser/should_compile/T20718b.stderr
index 79b5d67bb3..6370f1cbcc 100644
--- a/testsuite/tests/parser/should_compile/T20718b.stderr
+++ b/testsuite/tests/parser/should_compile/T20718b.stderr
@@ -17,7 +17,11 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T20718b.hs:8:1 }
+       { T20718b.hs:7:1-21 })))
     (EpaCommentsBalanced
      [(L
        (Anchor
@@ -51,13 +55,7 @@
         (EpaLineComment
          "-- trailing comment 2")
         { T20718b.hs:6:1-21 }))]
-     [(L
-       (Anchor
-        { T20718b.hs:8:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T20718b.hs:7:1-21 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/parser/should_compile/T20846.stderr b/testsuite/tests/parser/should_compile/T20846.stderr
index edacbd9ff6..7cb906a78a 100644
--- a/testsuite/tests/parser/should_compile/T20846.stderr
+++ b/testsuite/tests/parser/should_compile/T20846.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T20846.hs:5:1 }
+       { T20846.hs:4:10-18 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { T20846.hs:5:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T20846.hs:5:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/printer/T18791.stderr b/testsuite/tests/printer/T18791.stderr
index 52c97faba4..28727aabf6 100644
--- a/testsuite/tests/printer/T18791.stderr
+++ b/testsuite/tests/printer/T18791.stderr
@@ -17,16 +17,14 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { T18791.hs:6:1 }
+       { T18791.hs:5:17 })))
     (EpaCommentsBalanced
      []
-     [(L
-       (Anchor
-        { T18791.hs:6:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { T18791.hs:6:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/testsuite/tests/printer/Test20297.stdout b/testsuite/tests/printer/Test20297.stdout
index 9a220e21db..df6f3347f9 100644
--- a/testsuite/tests/printer/Test20297.stdout
+++ b/testsuite/tests/printer/Test20297.stdout
@@ -17,7 +17,11 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { Test20297.hs:12:1 }
+       { Test20297.hs:11:22-26 })))
     (EpaCommentsBalanced
      [(L
        (Anchor
@@ -27,13 +31,7 @@
         (EpaBlockComment
          "{-# OPTIONS -ddump-parsed-ast #-}")
         { Test20297.hs:1:1 }))]
-     [(L
-       (Anchor
-        { Test20297.hs:12:1 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { Test20297.hs:12:1 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
@@ -364,7 +362,11 @@
       (Nothing)
       (Nothing)
       []
-      []))
+      [])
+     (Just
+      ((,)
+       { Test20297.ppr.hs:9:25 }
+       { Test20297.ppr.hs:9:20-24 })))
     (EpaCommentsBalanced
      [(L
        (Anchor
@@ -374,13 +376,7 @@
         (EpaBlockComment
          "{-# OPTIONS -ddump-parsed-ast #-}")
         { Test20297.ppr.hs:1:1 }))]
-     [(L
-       (Anchor
-        { Test20297.ppr.hs:9:25 }
-        (UnchangedAnchor))
-       (EpaComment
-        (EpaEofComment)
-        { Test20297.ppr.hs:9:20 }))]))
+     []))
    (VirtualBraces
     (1))
    (Nothing)
diff --git a/utils/check-exact/ExactPrint.hs b/utils/check-exact/ExactPrint.hs
index 52fb4136ec..57389565b4 100644
--- a/utils/check-exact/ExactPrint.hs
+++ b/utils/check-exact/ExactPrint.hs
@@ -114,6 +114,7 @@ defaultEPState = EPState
              , uExtraDP = Nothing
              , epComments = []
              , epCommentsApplied = []
+             , epEof = Nothing
              }
 
 
@@ -188,6 +189,7 @@ data EPState = EPState
              -- Shared
              , epComments :: ![Comment]
              , epCommentsApplied :: ![[Comment]]
+             , epEof :: !(Maybe (RealSrcSpan, RealSrcSpan))
              }
 
 -- ---------------------------------------------------------------------
@@ -238,11 +240,7 @@ instance HasEntry (EpAnn a) where
 fromAnn' :: (HasEntry a) => a -> Entry
 fromAnn' an = case fromAnn an of
   NoEntryVal -> NoEntryVal
-  Entry a c _ u -> Entry a c' FlushComments u
-    where
-      c' = case c of
-        EpaComments cs -> EpaCommentsBalanced (filterEofComment False cs) (filterEofComment True cs)
-        EpaCommentsBalanced cp ct -> EpaCommentsBalanced cp ct
+  Entry a c _ u -> Entry a c FlushComments u
 
 -- ---------------------------------------------------------------------
 
@@ -355,7 +353,7 @@ enterAnn (Entry anchor' cs flush canUpdateAnchor) a = do
 
   let mflush = when (flush == FlushComments) $ do
         debugM $ "flushing comments in enterAnn:" ++ showAst cs
-        flushComments (getFollowingComments cs ++ filterEofComment True (priorComments cs))
+        flushComments (getFollowingComments cs)
 
   advance edp
   a' <- exact a
@@ -369,6 +367,17 @@ enterAnn (Entry anchor' cs flush canUpdateAnchor) a = do
       mapM_ printOneComment (map tokComment $ getFollowingComments cs)
       debugM $ "ending trailing comments"
 
+  eof <- getEofPos
+  case eof of
+    Nothing -> return ()
+    Just (pos, prior) -> do
+       let dp = if pos == prior
+             then (DifferentLine 1 0)
+             else origDelta pos prior
+       debugM $ "EOF:(pos,prior,dp) =" ++ showGhc (ss2pos pos, ss2pos prior, dp)
+       printStringAtLsDelta dp ""
+       setEofPos Nothing -- Only do this once
+
   let newAchor = anchor' { anchor_op = MovedAnchor edp }
   let r = case canUpdateAnchor of
             CanUpdateAnchor -> setAnnotationAnchor a' newAchor (mkEpaComments (priorCs++ postCs) [])
@@ -413,23 +422,12 @@ addComments csNew = do
 -- ones in the state.
 flushComments :: (Monad m, Monoid w) => [LEpaComment] -> EP w m ()
 flushComments trailing = do
-  addCommentsA (filterEofComment False trailing)
+  addCommentsA trailing
   cs <- getUnallocatedComments
   debugM $ "flushing comments starting"
   mapM_ printOneComment (sortComments cs)
-  debugM $ "flushing comments:EOF:trailing:" ++ showAst (trailing)
-  debugM $ "flushing comments:EOF:" ++ showAst (filterEofComment True trailing)
-  mapM_ printOneComment (map tokComment (filterEofComment True trailing))
   debugM $ "flushing comments done"
 
-filterEofComment :: Bool -> [LEpaComment] -> [LEpaComment]
-filterEofComment keep cs = fixCs cs
-  where
-      notEof com = case com of
-       L _ (GHC.EpaComment (EpaEofComment) _) -> keep
-       _ -> not keep
-      fixCs c = filter notEof c
-
 -- ---------------------------------------------------------------------
 
 -- |In order to interleave annotations into the stream, we turn them into
@@ -1397,6 +1395,13 @@ instance ExactPrint (HsModule GhcPs) where
           EpAnnNotUsed -> (am_decls $ anns an0)
           EpAnn _ r _ -> r
 
+    -- Print EOF
+    case am_eof $ anns an of
+      Nothing -> return ()
+      Just (pos, prior) -> do
+        debugM $ "am_eof:" ++ showGhc (pos, prior)
+        setEofPos (Just (pos, prior))
+
     let anf = an0 { anns = (anns an0) { am_decls = am_decls' }}
     debugM $ "HsModule, anf=" ++ showAst anf
 
@@ -4761,7 +4766,7 @@ printStringAtLsDelta cl s = do
         -- `debug` ("printStringAtLsDelta:(pos,s):" ++ show (undelta p cl colOffset,s))
       p' <- getPosP
       d <- getPriorEndD
-      debugM $ "printStringAtLsDelta:(pos,p',d,s):" ++ show (undelta p cl colOffset,p',d,s)
+      debugM $ "printStringAtLsDelta:(pos,p,p',d,s):" ++ show (undelta p cl colOffset,p,p',d,s)
     else return () `debug` ("printStringAtLsDelta:bad delta for (mc,s):" ++ show (cl,s))
 
 -- ---------------------------------------------------------------------
@@ -4873,6 +4878,14 @@ setAnchorU rss = do
   debugM $ "setAnchorU:" ++ show (rs2range rss)
   modify (\s -> s { uAnchorSpan = rss })
 
+getEofPos :: (Monad m, Monoid w) => EP w m (Maybe (RealSrcSpan, RealSrcSpan))
+getEofPos = gets epEof
+
+setEofPos :: (Monad m, Monoid w) => Maybe (RealSrcSpan, RealSrcSpan) -> EP w m ()
+setEofPos l = modify (\s -> s {epEof = l})
+
+-- ---------------------------------------------------------------------
+
 getUnallocatedComments :: (Monad m, Monoid w) => EP w m [Comment]
 getUnallocatedComments = gets epComments
 
diff --git a/utils/check-exact/Main.hs b/utils/check-exact/Main.hs
index 87921ac3e8..f286355cc1 100644
--- a/utils/check-exact/Main.hs
+++ b/utils/check-exact/Main.hs
@@ -36,7 +36,8 @@ import GHC.Data.FastString
 -- ---------------------------------------------------------------------
 
 _tt :: IO ()
-_tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/ghc/_build/stage1/lib/"
+_tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/worktree/master/_build/stage1/lib/"
+-- _tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/ghc/_build/stage1/lib/"
 -- _tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/worktree/exactprint/_build/stage1/lib"
 -- _tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/worktree/epw/_build/stage1/lib"
 
@@ -58,7 +59,7 @@ _tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/ghc/_build/stage1/
  -- "../../testsuite/tests/ghc-api/exactprint/AddDecl2.hs" (Just changeAddDecl2)
  -- "../../testsuite/tests/ghc-api/exactprint/AddDecl3.hs" (Just changeAddDecl3)
  -- "../../testsuite/tests/ghc-api/exactprint/LocalDecls.hs" (Just changeLocalDecls)
- -- "../../testsuite/tests/ghc-api/exactprint/LocalDecls2.hs" (Just changeLocalDecls2)
+ "../../testsuite/tests/ghc-api/exactprint/LocalDecls2.hs" (Just changeLocalDecls2)
  -- "../../testsuite/tests/ghc-api/exactprint/WhereIn3a.hs" (Just changeWhereIn3a)
  -- "../../testsuite/tests/ghc-api/exactprint/WhereIn3b.hs" (Just changeWhereIn3b)
  -- "../../testsuite/tests/ghc-api/exactprint/AddLocalDecl1.hs" (Just addLocaLDecl1)
@@ -194,7 +195,7 @@ _tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/ghc/_build/stage1/
  -- "../../testsuite/tests/printer/Test19834.hs" Nothing
  -- "../../testsuite/tests/printer/Test19840.hs" Nothing
  -- "../../testsuite/tests/printer/Test19850.hs" Nothing
- "../../testsuite/tests/printer/Test20258.hs" Nothing
+ -- "../../testsuite/tests/printer/Test20258.hs" Nothing
  -- "../../testsuite/tests/printer/PprLinearArrow.hs" Nothing
  -- "../../testsuite/tests/printer/PprSemis.hs" Nothing
  -- "../../testsuite/tests/printer/PprEmptyMostly.hs" Nothing
diff --git a/utils/check-exact/Orphans.hs b/utils/check-exact/Orphans.hs
index 1403324861..f6000288b0 100644
--- a/utils/check-exact/Orphans.hs
+++ b/utils/check-exact/Orphans.hs
@@ -89,4 +89,4 @@ instance Default EpAnnSumPat where
   def = EpAnnSumPat def  def  def
 
 instance Default AnnsModule where
-  def = AnnsModule [] mempty
+  def = AnnsModule [] mempty Nothing
diff --git a/utils/check-exact/Transform.hs b/utils/check-exact/Transform.hs
index 13c089eb71..3e3ebdcb39 100644
--- a/utils/check-exact/Transform.hs
+++ b/utils/check-exact/Transform.hs
@@ -709,15 +709,6 @@ commentOrigDelta (L (GHC.Anchor la _) (GHC.EpaComment t pp))
 
 -- ---------------------------------------------------------------------
 
-
--- | For comment-related deltas starting on a new line we have an
--- off-by-one problem. Adjust
-tweakDelta :: DeltaPos  -> DeltaPos
-tweakDelta (SameLine d) = SameLine d
-tweakDelta (DifferentLine l d) = DifferentLine l (d-1)
-
--- ---------------------------------------------------------------------
-
 balanceSameLineComments :: (Monad m)
   => LMatch GhcPs (LHsExpr GhcPs) -> TransformT m (LMatch GhcPs (LHsExpr GhcPs))
 balanceSameLineComments (L la (Match anm mctxt pats (GRHSs x grhss lb))) = do
diff --git a/utils/check-exact/Utils.hs b/utils/check-exact/Utils.hs
index 91d9cd5827..b60c989bcf 100644
--- a/utils/check-exact/Utils.hs
+++ b/utils/check-exact/Utils.hs
@@ -172,6 +172,25 @@ isPointSrcSpan ss = spanLength ss == 0
 
 -- ---------------------------------------------------------------------
 
+origDelta :: RealSrcSpan -> RealSrcSpan -> DeltaPos
+origDelta pos pp = op
+  where
+    (r,c) = ss2posEnd pp
+
+    op = if r == 0
+           then (             ss2delta (r,c+1) pos)
+           else (tweakDelta $ ss2delta (r,c  ) pos)
+
+-- ---------------------------------------------------------------------
+
+-- | For comment-related deltas starting on a new line we have an
+-- off-by-one problem. Adjust
+tweakDelta :: DeltaPos  -> DeltaPos
+tweakDelta (SameLine d) = SameLine d
+tweakDelta (DifferentLine l d) = DifferentLine l (d-1)
+
+-- ---------------------------------------------------------------------
+
 -- |Given a list of items and a list of keys, returns a list of items
 -- ordered by their position in the list of keys.
 orderByKey :: [(RealSrcSpan,a)] -> [RealSrcSpan] -> [(RealSrcSpan,a)]