EPA: Do not collect comments from end of file

In Parser.y semis1 production triggers for the virtual semi at the end
of the file. This is detected by it being zero length.

In this case, do not extend the span being used to gather comments, so
any final comments are allocated at the module level instead.

8 files changed, 188 insertions, 47 deletions

diff --git a/testsuite/tests/ghc-api/exactprint/RmDecl4.expected.hs b/testsuite/tests/ghc-api/exactprint/RmDecl4.expected.hs
index 9a36673062..e7c71dbd08 100644
--- a/testsuite/tests/ghc-api/exactprint/RmDecl4.expected.hs
+++ b/testsuite/tests/ghc-api/exactprint/RmDecl4.expected.hs
@@ -7,5 +7,4 @@ ff y = y + zz + xx
 
 zz = 1
 
-
 -- EOF
diff --git a/testsuite/tests/ghc-api/exactprint/Test20239.stderr b/testsuite/tests/ghc-api/exactprint/Test20239.stderr
index 8bfb5085ce..b89a29fbf2 100644
--- a/testsuite/tests/ghc-api/exactprint/Test20239.stderr
+++ b/testsuite/tests/ghc-api/exactprint/Test20239.stderr
@@ -24,7 +24,14 @@
        { Test20239.hs:7:34-63 })))
     (EpaCommentsBalanced
      []
-     []))
+     [(L
+       (Anchor
+        { Test20239.hs:7:34-63 }
+        (UnchangedAnchor))
+       (EpaComment
+        (EpaLineComment
+         "-- ^ Run any arbitrary IO code")
+        { Test20239.hs:6:86 }))]))
    (VirtualBraces
     (1))
    (Nothing)
@@ -50,15 +57,7 @@
                     (EpaComment
                      (EpaLineComment
                       "-- | Leading Haddock Comment")
-                     { Test20239.hs:1:18-22 }))
-                  ,(L
-                    (Anchor
-                     { Test20239.hs:7:34-63 }
-                     (UnchangedAnchor))
-                    (EpaComment
-                     (EpaLineComment
-                      "-- ^ Run any arbitrary IO code")
-                     { Test20239.hs:6:86 }))])) { Test20239.hs:(4,1)-(6,86) })
+                     { Test20239.hs:1:18-22 }))])) { Test20239.hs:(4,1)-(6,86) })
     (InstD
      (NoExtField)
      (DataFamInstD
diff --git a/testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.hs b/testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.hs
new file mode 100644
index 0000000000..6c3de63737
--- /dev/null
+++ b/testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.hs
@@ -0,0 +1,8 @@
+module ZeroWidthSemi where
+
+-- leading comments
+
+-- Function comment
+a = 0
+
+-- Trailing comment, should be in HsModule extension point
diff --git a/testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr b/testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr
new file mode 100644
index 0000000000..13937cd36b
--- /dev/null
+++ b/testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr
@@ -0,0 +1,134 @@
+
+==================== Parser AST ====================
+
+(L
+ { ZeroWidthSemi.hs:1:1 }
+ (HsModule
+  (XModulePs
+   (EpAnn
+    (Anchor
+     { ZeroWidthSemi.hs:1:1 }
+     (UnchangedAnchor))
+    (AnnsModule
+     [(AddEpAnn AnnModule (EpaSpan { ZeroWidthSemi.hs:1:1-6 }))
+     ,(AddEpAnn AnnWhere (EpaSpan { ZeroWidthSemi.hs:1:22-26 }))]
+     (AnnList
+      (Nothing)
+      (Nothing)
+      (Nothing)
+      []
+      [])
+     (Just
+      ((,)
+       { ZeroWidthSemi.hs:9:1 }
+       { ZeroWidthSemi.hs:8:1-58 })))
+    (EpaCommentsBalanced
+     [(L
+       (Anchor
+        { ZeroWidthSemi.hs:3:1-19 }
+        (UnchangedAnchor))
+       (EpaComment
+        (EpaLineComment
+         "-- leading comments")
+        { ZeroWidthSemi.hs:1:22-26 }))]
+     [(L
+       (Anchor
+        { ZeroWidthSemi.hs:8:1-58 }
+        (UnchangedAnchor))
+       (EpaComment
+        (EpaLineComment
+         "-- Trailing comment, should be in HsModule extension point")
+        { ZeroWidthSemi.hs:6:5 }))]))
+   (VirtualBraces
+    (1))
+   (Nothing)
+   (Nothing))
+  (Just
+   (L
+    (SrcSpanAnn (EpAnnNotUsed) { ZeroWidthSemi.hs:1:8-20 })
+    {ModuleName: ZeroWidthSemi}))
+  (Nothing)
+  []
+  [(L
+    (SrcSpanAnn (EpAnn
+                 (Anchor
+                  { ZeroWidthSemi.hs:6:1-5 }
+                  (UnchangedAnchor))
+                 (AnnListItem
+                  [])
+                 (EpaComments
+                  [(L
+                    (Anchor
+                     { ZeroWidthSemi.hs:5:1-19 }
+                     (UnchangedAnchor))
+                    (EpaComment
+                     (EpaLineComment
+                      "-- Function comment")
+                     { ZeroWidthSemi.hs:3:1-19 }))])) { ZeroWidthSemi.hs:6:1-5 })
+    (ValD
+     (NoExtField)
+     (FunBind
+      (NoExtField)
+      (L
+       (SrcSpanAnn (EpAnnNotUsed) { ZeroWidthSemi.hs:6:1 })
+       (Unqual
+        {OccName: a}))
+      (MG
+       (FromSource)
+       (L
+        (SrcSpanAnn (EpAnnNotUsed) { ZeroWidthSemi.hs:6:1-5 })
+        [(L
+          (SrcSpanAnn (EpAnnNotUsed) { ZeroWidthSemi.hs:6:1-5 })
+          (Match
+           (EpAnn
+            (Anchor
+             { ZeroWidthSemi.hs:6:1-5 }
+             (UnchangedAnchor))
+            []
+            (EpaComments
+             []))
+           (FunRhs
+            (L
+             (SrcSpanAnn (EpAnnNotUsed) { ZeroWidthSemi.hs:6:1 })
+             (Unqual
+              {OccName: a}))
+            (Prefix)
+            (NoSrcStrict))
+           []
+           (GRHSs
+            (EpaComments
+             [])
+            [(L
+              (SrcSpanAnn
+               (EpAnnNotUsed)
+               { ZeroWidthSemi.hs:6:3-5 })
+              (GRHS
+               (EpAnn
+                (Anchor
+                 { ZeroWidthSemi.hs:6:3-5 }
+                 (UnchangedAnchor))
+                (GrhsAnn
+                 (Nothing)
+                 (AddEpAnn AnnEqual (EpaSpan { ZeroWidthSemi.hs:6:3 })))
+                (EpaComments
+                 []))
+               []
+               (L
+                (SrcSpanAnn (EpAnnNotUsed) { ZeroWidthSemi.hs:6:5 })
+                (HsOverLit
+                 (EpAnn
+                  (Anchor
+                   { ZeroWidthSemi.hs:6:5 }
+                   (UnchangedAnchor))
+                  (NoEpAnns)
+                  (EpaComments
+                   []))
+                 (OverLit
+                  (NoExtField)
+                  (HsIntegral
+                   (IL
+                    (SourceText 0)
+                    (False)
+                    (0))))))))]
+            (EmptyLocalBinds
+             (NoExtField)))))])))))]))
diff --git a/testsuite/tests/ghc-api/exactprint/all.T b/testsuite/tests/ghc-api/exactprint/all.T
index 97d94b566c..825d57c339 100644
--- a/testsuite/tests/ghc-api/exactprint/all.T
+++ b/testsuite/tests/ghc-api/exactprint/all.T
@@ -37,3 +37,4 @@ test('RmTypeSig2',    ignore_stderr, makefile_test, ['RmTypeSig2'])
 test('AddHiding1',    ignore_stderr, makefile_test, ['AddHiding1'])
 test('AddHiding2',    ignore_stderr, makefile_test, ['AddHiding2'])
 test('Test20239',  normal, compile_fail, ['-dsuppress-uniques -ddump-parsed-ast -dkeep-comments'])
+test('ZeroWidthSemi',  normal, compile, ['-dsuppress-uniques -ddump-parsed-ast -dkeep-comments'])
diff --git a/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr b/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr
index 6050639d73..4eb1a179db 100644
--- a/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr
+++ b/testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr
@@ -82,15 +82,7 @@
                     (EpaComment
                      (EpaLineComment
                       "-- comment 2 for foo")
-                     { DumpParsedAstComments.hs:9:1-20 }))
-                  ,(L
-                    (Anchor
-                     { DumpParsedAstComments.hs:15:1-20 }
-                     (UnchangedAnchor))
-                    (EpaComment
-                     (EpaLineComment
-                      "-- | Haddock comment")
-                     { DumpParsedAstComments.hs:13:3
+                     { DumpParsedAstComments.hs:9:1-20
                         }))])) { DumpParsedAstComments.hs:(11,1)-(13,3) })
     (ValD
      (NoExtField)
@@ -219,7 +211,15 @@
                  (AnnListItem
                   [])
                  (EpaComments
-                  [])) { DumpParsedAstComments.hs:16:1-23 })
+                  [(L
+                    (Anchor
+                     { DumpParsedAstComments.hs:15:1-20 }
+                     (UnchangedAnchor))
+                    (EpaComment
+                     (EpaLineComment
+                      "-- | Haddock comment")
+                     { DumpParsedAstComments.hs:13:3
+                        }))])) { DumpParsedAstComments.hs:16:1-23 })
     (ValD
      (NoExtField)
      (FunBind
diff --git a/testsuite/tests/parser/should_compile/T20718.stderr b/testsuite/tests/parser/should_compile/T20718.stderr
index bd071a0227..16eeaa4e69 100644
--- a/testsuite/tests/parser/should_compile/T20718.stderr
+++ b/testsuite/tests/parser/should_compile/T20718.stderr
@@ -55,7 +55,22 @@
         (EpaLineComment
          "-- before 2")
         { T20718.hs:5:1-11 }))]
-     []))
+     [(L
+       (Anchor
+        { T20718.hs:10:1-8 }
+        (UnchangedAnchor))
+       (EpaComment
+        (EpaLineComment
+         "-- end 1")
+        { T20718.hs:8:5 }))
+     ,(L
+       (Anchor
+        { T20718.hs:11:1-8 }
+        (UnchangedAnchor))
+       (EpaComment
+        (EpaLineComment
+         "-- end 2")
+        { T20718.hs:10:1-8 }))]))
    (VirtualBraces
     (1))
    (Nothing)
@@ -74,22 +89,7 @@
                  (AnnListItem
                   [])
                  (EpaComments
-                  [(L
-                    (Anchor
-                     { T20718.hs:10:1-8 }
-                     (UnchangedAnchor))
-                    (EpaComment
-                     (EpaLineComment
-                      "-- end 1")
-                     { T20718.hs:8:5 }))
-                  ,(L
-                    (Anchor
-                     { T20718.hs:11:1-8 }
-                     (UnchangedAnchor))
-                    (EpaComment
-                     (EpaLineComment
-                      "-- end 2")
-                     { T20718.hs:10:1-8 }))])) { T20718.hs:8:1-5 })
+                  [])) { T20718.hs:8:1-5 })
     (ValD
      (NoExtField)
      (FunBind
diff --git a/testsuite/tests/printer/Test20297.stdout b/testsuite/tests/printer/Test20297.stdout
index df6f3347f9..180078c16a 100644
--- a/testsuite/tests/printer/Test20297.stdout
+++ b/testsuite/tests/printer/Test20297.stdout
@@ -50,14 +50,7 @@
                  (AnnListItem
                   [])
                  (EpaComments
-                  [(L
-                    (Anchor
-                     { Test20297.hs:7:9-19 }
-                     (UnchangedAnchor))
-                    (EpaComment
-                     (EpaLineComment
-                      "-- comment1")
-                     { Test20297.hs:7:3-7 }))])) { Test20297.hs:(5,1)-(7,7) })
+                  [])) { Test20297.hs:(5,1)-(7,7) })
     (ValD
      (NoExtField)
      (FunBind
@@ -150,7 +143,14 @@
                  (AnnListItem
                   [])
                  (EpaComments
-                  [])) { Test20297.hs:(9,1)-(11,26) })
+                  [(L
+                    (Anchor
+                     { Test20297.hs:7:9-19 }
+                     (UnchangedAnchor))
+                    (EpaComment
+                     (EpaLineComment
+                      "-- comment1")
+                     { Test20297.hs:7:3-7 }))])) { Test20297.hs:(9,1)-(11,26) })
     (ValD
      (NoExtField)
      (FunBind