EPA: order of semicolons and comments for top-level decls is wrong

A comment followed by a semicolon at the top level resulted in the
preceding comments being attached to the following declaration.

Capture the comments as belonging to the declaration preceding the
semicolon instead.

Closes #20258

1 files changed, 11 insertions, 6 deletions

diff --git a/compiler/GHC/Parser.y b/compiler/GHC/Parser.y
index 1c0c65bb96..732a03f7d5 100644
--- a/compiler/GHC/Parser.y
+++ b/compiler/GHC/Parser.y
@@ -1066,9 +1066,9 @@ qcname  :: { LocatedN RdrName }  -- Variable or type constructor
 -- top handles the fact that these may be optional.
 
 -- One or more semicolons
-semis1  :: { [TrailingAnn] }
-semis1  : semis1 ';'  { if isZeroWidthSpan (gl $2) then $1 else (AddSemiAnn (glAA $2) : $1) }
-        | ';'         { msemi $1 }
+semis1  :: { Located [TrailingAnn] }
+semis1  : semis1 ';'  { sLL $1 $> $ if isZeroWidthSpan (gl $2) then (unLoc $1) else (AddSemiAnn (glAA $2) : (unLoc $1)) }
+        | ';'         { sL1 $1 $ msemi $1 }
 
 -- Zero or more semicolons
 semis   :: { [TrailingAnn] }
@@ -1085,7 +1085,7 @@ importdecls
 importdecls_semi :: { [LImportDecl GhcPs] }
 importdecls_semi
         : importdecls_semi importdecl semis1
-                                {% do { i <- amsA $2 $3
+                                {% do { i <- amsAl $2 (comb2 (reLoc $2) $3) (unLoc $3)
                                       ; return (i : $1)} }
         | {- empty -}           { [] }
 
@@ -1187,7 +1187,7 @@ topdecls :: { OrdList (LHsDecl GhcPs) }
 
 -- May have trailing semicolons, can be empty
 topdecls_semi :: { OrdList (LHsDecl GhcPs) }
-        : topdecls_semi topdecl semis1 {% do { t <- amsA $2 $3
+        : topdecls_semi topdecl semis1 {% do { t <- amsAl $2 (comb2 (reLoc $2) $3) (unLoc $3)
                                              ; return ($1 `snocOL` t) }}
         | {- empty -}                  { nilOL }
 
@@ -1200,7 +1200,7 @@ topdecls_cs :: { OrdList (LHsDecl GhcPs) }
 
 -- May have trailing semicolons, can be empty
 topdecls_cs_semi :: { OrdList (LHsDecl GhcPs) }
-        : topdecls_cs_semi topdecl_cs semis1 {% do { t <- amsA $2 $3
+        : topdecls_cs_semi topdecl_cs semis1 {% do { t <- amsAl $2 (comb2 (reLoc $2) $3) (unLoc $3)
                                                    ; return ($1 `snocOL` t) }}
         | {- empty -}                  { nilOL }
 
@@ -4254,6 +4254,11 @@ amsA (L l a) bs = do
   cs <- getCommentsFor (locA l)
   return (L (addAnnsA l bs cs) a)
 
+amsAl :: MonadP m => LocatedA a -> SrcSpan -> [TrailingAnn] -> m (LocatedA a)
+amsAl (L l a) loc bs = do
+  cs <- getCommentsFor loc
+  return (L (addAnnsA l bs cs) a)
+
 amsrc :: MonadP m => Located a -> AnnContext -> m (LocatedC a)
 amsrc a@(L l _) bs = do
   cs <- getCommentsFor l