From f75a5dbe2ec9fbc67df0936333e0665b033f9e22 Mon Sep 17 00:00:00 2001
From: Jiasen Wu <jiasenwu@hotmail.com>
Date: Sat, 15 Dec 2018 23:17:37 +0100
Subject: [PATCH] bug fix. add a space in promoted list/tuple of some promoted
 type

---
 src/Language/Haskell/Exts/Pretty.hs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/Language/Haskell/Exts/Pretty.hs b/src/Language/Haskell/Exts/Pretty.hs
index dfe574eb..2e9da313 100644
--- a/src/Language/Haskell/Exts/Pretty.hs
+++ b/src/Language/Haskell/Exts/Pretty.hs
@@ -892,14 +892,25 @@ instance  Pretty (Promoted l) where
       PromotedCon _ hasQuote qn ->
         addQuote hasQuote (pretty qn)
       PromotedList _ hasQuote list ->
-        addQuote hasQuote $ bracketList . punctuate comma . map pretty $ list
+        addQuote hasQuote $ brackets . addSpace list . prettyList $ list
       PromotedTuple _ list ->
-        addQuote True $ parenList $ map pretty list
+        addQuote True $ parens . addSpace list . prettyList $ list
       PromotedUnit {} -> addQuote True $ text "()"
     where
       addQuote True doc = char '\'' <> doc
       addQuote False doc = doc
 
+      checkQuote (PromotedCon _ q _) = q
+      checkQuote (PromotedList _ q _) = q
+      checkQuote (PromotedTuple _ _) = True
+      checkQuote _ = False
+
+      addSpace (TyPromoted _ l0:_) | checkQuote l0 = (space <>)
+      addSpace _ = id
+
+      prettyList = myFsepSimple . punctuate comma . map pretty
+
+
 instance  Pretty (TyVarBind l) where
         pretty (KindedVar _ var kind) = parens $ myFsep [pretty var, text "::", pretty kind]
         pretty (UnkindedVar _ var)    = pretty var