From f822619d71d270adcfb09e30dcf7ba0900f3b63a Mon Sep 17 00:00:00 2001
From: Alan Zimmerman <alan.zimm@gmail.com>
Date: Mon, 7 Mar 2022 22:23:29 +0000
Subject: EPA: let stmt with semicolon has wrong anchor

The code

   let ;x =1

Captures the semicolon annotation, but did not widen the anchor in the
ValBinds.

Fix that.

Closes #20247
---
 compiler/GHC/Parser.y                | 2 +-
 compiler/GHC/Parser/Annotation.hs    | 8 +++++++-
 compiler/GHC/Parser/PostProcess.hs   | 7 ++++++-
 testsuite/tests/printer/Makefile     | 6 ++++++
 testsuite/tests/printer/Test20247.hs | 4 ++++
 testsuite/tests/printer/all.T        | 1 +
 6 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100644 testsuite/tests/printer/Test20247.hs

diff --git a/compiler/GHC/Parser.y b/compiler/GHC/Parser.y
index a11a438d89..90b17018ff 100644
--- a/compiler/GHC/Parser.y
+++ b/compiler/GHC/Parser.y
@@ -1791,7 +1791,7 @@ binds   ::  { Located (HsLocalBinds GhcPs) }
                                                 -- No type declarations
         : decllist          {% do { val_binds <- cvBindGroup (unLoc $ snd $ unLoc $1)
                                   ; cs <- getCommentsFor (gl $1)
-                                  ; return (sL1 $1 $ HsValBinds (EpAnn (glR $1) (fst $ unLoc $1) cs) val_binds)} }
+                                  ; return (sL1 $1 $ HsValBinds (fixValbindsAnn $ EpAnn (glR $1) (fst $ unLoc $1) cs) val_binds)} }
 
         | '{'            dbinds '}'     {% acs (\cs -> (L (comb3 $1 $2 $3)
                                              $ HsIPBinds (EpAnn (glR $1) (AnnList (Just$ glR $2) (Just $ moc $1) (Just $ mcc $3) [] []) cs) (IPBinds noExtField (reverse $ unLoc $2)))) }
diff --git a/compiler/GHC/Parser/Annotation.hs b/compiler/GHC/Parser/Annotation.hs
index 1f48615aec..4f7525842f 100644
--- a/compiler/GHC/Parser/Annotation.hs
+++ b/compiler/GHC/Parser/Annotation.hs
@@ -43,7 +43,8 @@ module GHC.Parser.Annotation (
   AnnSortKey(..),
 
   -- ** Trailing annotations in lists
-  TrailingAnn(..), addTrailingAnnToA, addTrailingAnnToL, addTrailingCommaToN,
+  TrailingAnn(..), trailingAnnToAddEpAnn,
+  addTrailingAnnToA, addTrailingAnnToL, addTrailingCommaToN,
 
   -- ** Utilities for converting between different 'GenLocated' when
   -- ** we do not care about the annotations.
@@ -806,6 +807,11 @@ data AnnSortKey
 
 -- ---------------------------------------------------------------------
 
+-- | Convert a 'TrailingAnn' to an 'AddEpAnn'
+trailingAnnToAddEpAnn :: TrailingAnn -> AddEpAnn
+trailingAnnToAddEpAnn (AddSemiAnn ss)    = AddEpAnn AnnSemi ss
+trailingAnnToAddEpAnn (AddCommaAnn ss)   = AddEpAnn AnnComma ss
+trailingAnnToAddEpAnn (AddVbarAnn ss)    = AddEpAnn AnnVbar ss
 
 -- | Helper function used in the parser to add a 'TrailingAnn' items
 -- to an existing annotation.
diff --git a/compiler/GHC/Parser/PostProcess.hs b/compiler/GHC/Parser/PostProcess.hs
index b9be24259a..f5c7a513c7 100644
--- a/compiler/GHC/Parser/PostProcess.hs
+++ b/compiler/GHC/Parser/PostProcess.hs
@@ -37,6 +37,7 @@ module GHC.Parser.PostProcess (
         setRdrNameSpace,
         fromSpecTyVarBndr, fromSpecTyVarBndrs,
         annBinds,
+        fixValbindsAnn,
 
         cvBindGroup,
         cvBindsAndSigs,
@@ -471,6 +472,11 @@ patch_anchor r1 (Anchor r0 op) = Anchor r op
   where
     r = if srcSpanStartLine r0 < 0 then r1 else r0
 
+fixValbindsAnn :: EpAnn AnnList -> EpAnn AnnList
+fixValbindsAnn EpAnnNotUsed = EpAnnNotUsed
+fixValbindsAnn (EpAnn anchor (AnnList ma o c r t) cs)
+  = (EpAnn (widenAnchor anchor (map trailingAnnToAddEpAnn t)) (AnnList ma o c r t) cs)
+
 {- **********************************************************************
 
   #cvBinds-etc# Converting to @HsBinds@, etc.
@@ -1002,7 +1008,6 @@ checkTyClHdr is_cls ty
     newAnns (SrcSpanAnn EpAnnNotUsed l) (EpAnn as (AnnParen _ o c) cs) =
       let
         lr = combineRealSrcSpans (realSrcSpan l) (anchor as)
-        -- lr = widenAnchorR as (realSrcSpan l)
         an = (EpAnn (Anchor lr UnchangedAnchor) (NameAnn NameParens o (EpaSpan $ realSrcSpan l) c []) cs)
       in SrcSpanAnn an (RealSrcSpan lr Strict.Nothing)
     newAnns _ EpAnnNotUsed = panic "missing AnnParen"
diff --git a/testsuite/tests/printer/Makefile b/testsuite/tests/printer/Makefile
index 749315c60a..2c4195eeb1 100644
--- a/testsuite/tests/printer/Makefile
+++ b/testsuite/tests/printer/Makefile
@@ -734,6 +734,12 @@ Test20243:
 	$(CHECK_PPR)   $(LIBDIR) Test20243.hs
 	$(CHECK_EXACT) $(LIBDIR) Test20243.hs
 
+.PHONY: Test20247
+Test20247:
+	$(CHECK_PPR)   $(LIBDIR) Test20247.hs
+	$(CHECK_EXACT) $(LIBDIR) Test20247.hs
+
+
 .PHONY: Test20258
 Test20258:
 	$(CHECK_PPR)   $(LIBDIR) Test20258.hs
diff --git a/testsuite/tests/printer/Test20247.hs b/testsuite/tests/printer/Test20247.hs
new file mode 100644
index 0000000000..8c2521fe9a
--- /dev/null
+++ b/testsuite/tests/printer/Test20247.hs
@@ -0,0 +1,4 @@
+module Test20247 where
+
+foo = do
+  let ;x =1
diff --git a/testsuite/tests/printer/all.T b/testsuite/tests/printer/all.T
index 3d7c28e453..4562acc8e5 100644
--- a/testsuite/tests/printer/all.T
+++ b/testsuite/tests/printer/all.T
@@ -173,6 +173,7 @@ test('PprUnicodeSyntax', [ignore_stderr, req_ppr_deps], makefile_test, ['PprUnic
 test('PprCommentPlacement2', [ignore_stderr, req_ppr_deps], makefile_test, ['PprCommentPlacement2'])
 
 test('Test20243', [ignore_stderr, req_ppr_deps], makefile_test, ['Test20243'])
+test('Test20247', [ignore_stderr, req_ppr_deps], makefile_test, ['Test20247'])
 test('Test20258', [ignore_stderr, req_ppr_deps], makefile_test, ['Test20258'])
 test('Test20297', [ignore_stderr, req_ppr_deps], makefile_test, ['Test20297'])
 test('Test20846', [ignore_stderr, req_ppr_deps], makefile_test, ['Test20846'])
-- 
cgit v1.2.1