Fix issue with indentation after block-comments

data/15-regressions.blt

@@ -985,3 +985,11 @@ instance BMGuwigoc POtfuggj where
 
 #test bang-type
 data LabeledBool = LabeledBool !Int !Bool
+
+#test block-comment after let
+func = do
+  let cipInuihz = Vuozczdm.yhEfun tuhiuRasohy
+  let {- CAZEB mecwbd "Caa ||" -}
+      doeeRbaviceQzymin a b = olivhuwqbaq
+      iqnz biwomeJhhujy _ _ | biwomeJhhujy < volpoqAsizmHdwpl = pure 0
+  pure True

source/library/Language/Haskell/Brittany/Internal/S4_WriteBriDoc.hs

@@ -275,21 +275,53 @@ layoutBriDocM = \case
     layoutBriDocM bd
   BDFlushCommentsPrior loc bd -> do
     comms <- takeBefore loc
+    startCurY <- mGet <&> _lstate_curY
     printComments comms
     mModify (\s -> s + CommentCounter (length comms))
     mModify $ \s -> s
       { _lstate_markerForDelta = Nothing
-      , _lstate_plannedSpace = case _lstate_markerForDelta s of
+      , _lstate_plannedSpace =
+        case _lstate_markerForDelta s of
           Nothing -> _lstate_plannedSpace s
           Just m ->
             let p1 = (srcLocLine m, srcLocCol m)
                 p2 = (srcLocLine loc, srcLocCol loc)
-            -- traceShow (m, ExactPrint.pos2delta p1 p2) $ pure ()
+            in -- trace ("_lstate_plannedSpace = " ++ show (_lstate_plannedSpace s)
-            in case ExactPrint.pos2delta p1 p2 of
+               --   ++ ", _lstate_markerForDelta = " ++ show (_lstate_markerForDelta s)
-              SameLine{} -> _lstate_plannedSpace s
+               --   ++ ", _lstate_curY = " ++ show (_lstate_curY s)
+               --   ++ ", p1 = " ++ show p1
+               --   ++ ", p2 = " ++ show p2
+               --   ++ ", startCurY = " ++ show startCurY
+               --   -- ++ ", delta = " ++ show (ExactPrint.pos2delta p1 p2)
+               -- ) $
+              case ExactPrint.pos2delta p1 p2 of
+              SameLine iDelta -> case _lstate_plannedSpace s of
+                -- There is a delta after a marker. That should only happen
+                -- after a block-comment. And the marker-delta is SameLine,
+                -- so if layout doesn't force a newline we respect the marker
+                -- delta (i.e. respect whitespace immediately after a block
+                -- comment) or we just use the plan.
+                PlannedNone        -> PlannedSameline iDelta
+                PlannedSameline i  -> PlannedSameline (max (iDelta - 0) i)
+                p@PlannedNewline{} -> p
+                p@PlannedDelta{}   -> p
               DifferentLine n _ -> case _lstate_plannedSpace s of
-                PlannedNone       -> PlannedNone
+                -- Marker with DifferentLine delta means that we want to
-                PlannedSameline i -> PlannedDelta n (_lstate_curY s + i)
+                -- reproduce the newlines that were present in the input.
+                -- These will be emptylines in cases where it makes sense to
+                -- reproduce them, e.g. between statements in a do-block.
+                PlannedNone       -> PlannedDelta n startCurY
+                                     --             ^^^^^^^^^
+                                     --
+                                     -- after a block-comment, _lstate_curY
+                                     -- matches the end of the comment.
+                                     -- But to not break layout we need to
+                                     -- restore the original.
+                                     -- E.g. consider > let {-comm-}
+                                     --               >     x = 13
+                                     --
+                                     --             vvvvvvvvvvvvvvv
+                PlannedSameline i -> PlannedDelta n (startCurY + i)
                 PlannedNewline{}  -> PlannedNewline n
                 PlannedDelta _ i  -> PlannedDelta n i
       }

source/library/Language/Haskell/Brittany/Internal/WriteBriDoc/Operators.hs

@@ -152,7 +152,7 @@ layoutWriteComment absolute isBlock dp commentLines s = do -- TODO92 we don't mo
   mSet state
     { _lstate_plannedSpace    = if isBlock
       then case _lstate_plannedSpace state of
-        PlannedNone         -> PlannedSameline 1
+        p@PlannedNone       -> p
         p@PlannedSameline{} -> p
         PlannedNewline l ->
           if l <= y then PlannedSameline 1 else PlannedNewline (l - y)