From 9cac37a09ac0bc69ba1bd5b157fe8fafcbcc4597 Mon Sep 17 00:00:00 2001
From: mniip <mniip@mniip.com>
Date: Thu, 21 Dec 2023 12:55:23 +0100
Subject: [PATCH] Work around a bug in mergeWithKey

---
 src/Data/IntMap/Common/Refined.hs |  9 +++++++--
 src/Data/IntMap/Strict/Refined.hs | 11 +++++++++--
 src/Data/Map/Common/Refined.hs    |  9 +++++++--
 src/Data/Map/Strict/Refined.hs    |  9 +++++++--
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/src/Data/IntMap/Common/Refined.hs b/src/Data/IntMap/Common/Refined.hs
index 5f2a692..6627133 100644
--- a/src/Data/IntMap/Common/Refined.hs
+++ b/src/Data/IntMap/Common/Refined.hs
@@ -241,8 +241,13 @@ zipWithKey
   -> IntMap s c
 zipWithKey f (IntMap m1) (IntMap m2) = IntMap
   $ IntMap.mergeWithKey (\k x y -> Just $ f (unsafeKey k) x y)
-    (error "zipWithKey: bug: Data.IntMap.Refined has been subverted")
-    (error "zipWithKey: bug: Data.IntMap.Refined has been subverted")
+    (\m -> if IntMap.null m
+      then IntMap.empty
+      else error "zipWithKey: bug: Data.IntMap.Refined has been subverted")
+    (\m -> if IntMap.null m
+      then IntMap.empty
+      else error "zipWithKey: bug: Data.IntMap.Refined has been subverted")
+    --  ^ Work around https://github.com/haskell/containers/issues/979
     m1
     m2
 
diff --git a/src/Data/IntMap/Strict/Refined.hs b/src/Data/IntMap/Strict/Refined.hs
index dcd2f9e..d568b41 100644
--- a/src/Data/IntMap/Strict/Refined.hs
+++ b/src/Data/IntMap/Strict/Refined.hs
@@ -236,8 +236,15 @@ zipWithKey
   -> IntMap s c
 zipWithKey f (IntMap m1) (IntMap m2) = IntMap
   $ IntMap.mergeWithKey (\k x y -> Just $ f (unsafeKey k) x y)
-    (error "zipWithKey: bug: Data.IntMap.Strict.Refined has been subverted")
-    (error "zipWithKey: bug: Data.IntMap.Strict.Refined has been subverted")
+    (\m -> if IntMap.null m
+      then IntMap.empty
+      else
+        error "zipWithKey: bug: Data.IntMap.Strict.Refined has been subverted")
+    (\m -> if IntMap.null m
+      then IntMap.empty
+      else
+        error "zipWithKey: bug: Data.IntMap.Strict.Refined has been subverted")
+    --  ^ Work around https://github.com/haskell/containers/issues/979
     m1
     m2
 
diff --git a/src/Data/Map/Common/Refined.hs b/src/Data/Map/Common/Refined.hs
index 14fdd5a..a9db9e1 100644
--- a/src/Data/Map/Common/Refined.hs
+++ b/src/Data/Map/Common/Refined.hs
@@ -241,8 +241,13 @@ zipWithKey
   => (Key s k -> a -> b -> c) -> Map s k a -> Map s k b -> Map s k c
 zipWithKey f (Map m1) (Map m2) = Map
   $ Map.mergeWithKey (\k x y -> Just $ f (unsafeKey k) x y)
-    (error "zipWithKey: bug: Data.Map.Refined has been subverted")
-    (error "zipWithKey: bug: Data.Map.Refined has been subverted")
+    (\m -> if Map.null m
+      then Map.empty
+      else error "zipWithKey: bug: Data.Map.Refined has been subverted")
+    (\m -> if Map.null m
+      then Map.empty
+      else error "zipWithKey: bug: Data.Map.Refined has been subverted")
+    --  ^ Work around https://github.com/haskell/containers/issues/979
     m1
     m2
 
diff --git a/src/Data/Map/Strict/Refined.hs b/src/Data/Map/Strict/Refined.hs
index 2bac38d..ca48300 100644
--- a/src/Data/Map/Strict/Refined.hs
+++ b/src/Data/Map/Strict/Refined.hs
@@ -244,8 +244,13 @@ zipWithKey
   => (Key s k -> a -> b -> c) -> Map s k a -> Map s k b -> Map s k c
 zipWithKey f (Map m1) (Map m2) = Map
   $ Map.mergeWithKey (\k x y -> Just $ f (unsafeKey k) x y)
-    (error "zipWithKey: bug: Data.Map.Strict.Refined has been subverted")
-    (error "zipWithKey: bug: Data.Map.Strict.Refined has been subverted")
+    (\m -> if Map.null m
+      then Map.empty
+      else error "zipWithKey: bug: Data.Map.Strict.Refined has been subverted")
+    (\m -> if Map.null m
+      then Map.empty
+      else error "zipWithKey: bug: Data.Map.Strict.Refined has been subverted")
+    --  ^ Work around https://github.com/haskell/containers/issues/979
     m1
     m2