From 08451427279f15751bd762135117591d7e6cd6dc Mon Sep 17 00:00:00 2001
From: Lennart Spitzner <hexagoxel@hexagoxel.de>
Date: Fri, 23 Mar 2018 17:34:36 +0100
Subject: [PATCH] Fix let-in comment placement bug (fixes #110)

---
 src-literatetests/15-regressions.blt             | 10 +++++++++-
 .../Haskell/Brittany/Internal/Layouters/Expr.hs  | 16 +++++++++-------
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/src-literatetests/15-regressions.blt b/src-literatetests/15-regressions.blt
index 0498b5d..d84ec79 100644
--- a/src-literatetests/15-regressions.blt
+++ b/src-literatetests/15-regressions.blt
@@ -538,8 +538,16 @@ cs0 = 0 : [ c / Interval n | c <- cs | n <- [1..] ]
 {-# LANGUAGE TemplateHaskell #-}
 deriveFromJSON (unPrefix "assignPost") ''AssignmentPost
 
-#test issue 111
+#test issue 110
+main = -- a
+  let --b
+      x = 1 -- x
+      y = 2 -- y
+  in  do
+        print x
+        print y
 
+#test issue 111
 alternatives :: Parser (Maybe Text)
 alternatives =
   alternativeOne   -- first try this one
diff --git a/src/Language/Haskell/Brittany/Internal/Layouters/Expr.hs b/src/Language/Haskell/Brittany/Internal/Layouters/Expr.hs
index f8535e7..a5402ea 100644
--- a/src/Language/Haskell/Brittany/Internal/Layouters/Expr.hs
+++ b/src/Language/Haskell/Brittany/Internal/Layouters/Expr.hs
@@ -543,7 +543,9 @@ layoutExpr lexpr@(L _ expr) = do
         (layoutPatternBindFinal Nothing binderDoc Nothing clauseDocs Nothing hasComments)
     HsLet binds exp1 -> do
       expDoc1 <- docSharedWrapper layoutExpr exp1
-      mBindDocs <- layoutLocalBinds binds
+      -- We jump through some ugly hoops here to ensure proper sharing.
+      mBindDocs <- mapM (fmap (fmap return) . docWrapNodeRest lexpr . return)
+               =<< layoutLocalBinds binds
       let
         ifIndentLeftElse :: a -> a -> a
         ifIndentLeftElse x y =
@@ -560,7 +562,7 @@ layoutExpr lexpr@(L _ expr) = do
         Just [bindDoc] -> docAlt
           [ docSeq
               [ appSep $ docLit $ Text.pack "let"
-              , appSep $ docForceSingleline $ return bindDoc
+              , appSep $ docForceSingleline $ bindDoc
               , appSep $ docLit $ Text.pack "in"
               , docForceSingleline $ expDoc1
               ]
@@ -569,12 +571,12 @@ layoutExpr lexpr@(L _ expr) = do
                   [ docSeq
                       [ appSep $ docLit $ Text.pack "let"
                       , ifIndentLeftElse docForceSingleline docSetBaseAndIndent
-                      $ return bindDoc
+                      $ bindDoc
                       ]
                   , docAddBaseY BrIndentRegular
                   $ docPar
                     (docLit $ Text.pack "let")
-                    (docSetBaseAndIndent $ return bindDoc)
+                    (docSetBaseAndIndent $ bindDoc)
                   ]
               , docAlt
                   [ docSeq
@@ -607,7 +609,7 @@ layoutExpr lexpr@(L _ expr) = do
               [ docAddBaseY BrIndentRegular
               $ docPar
                 (docLit $ Text.pack "let")
-                (docSetBaseAndIndent $ docLines $ return <$> bindDocs)
+                (docSetBaseAndIndent $ docLines $ bindDocs)
               , docSeq
                 [ docLit $ Text.pack "in "
                 , docAddBaseY BrIndentRegular $ expDoc1
@@ -618,7 +620,7 @@ layoutExpr lexpr@(L _ expr) = do
             , docLines
               [ docSeq
                 [ appSep $ docLit $ Text.pack "let"
-                , docSetBaseAndIndent $ docLines $ return <$> bindDocs
+                , docSetBaseAndIndent $ docLines $ bindDocs
                 ]
               , docSeq
                 [ appSep $ docLit $ Text.pack "in "
@@ -631,7 +633,7 @@ layoutExpr lexpr@(L _ expr) = do
               [ docAddBaseY BrIndentRegular
               $ docPar
                 (docLit $ Text.pack "let")
-                (docSetBaseAndIndent $ docLines $ return <$> bindDocs)
+                (docSetBaseAndIndent $ docLines $ bindDocs)
               , docAddBaseY BrIndentRegular
               $ docPar
                 (docLit $ Text.pack "in")