From c904582015d5a8eed917d79a7f28ea2b5a8ddde3 Mon Sep 17 00:00:00 2001
From: Robert Payne <robertpayne@me.com>
Date: Sun, 28 Apr 2019 20:57:54 +1200
Subject: [PATCH] Fix layout constraint comparison

---
 Source/LayoutConstraint.swift | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/Source/LayoutConstraint.swift b/Source/LayoutConstraint.swift
index 8bb5ed2..9abb45f 100644
--- a/Source/LayoutConstraint.swift
+++ b/Source/LayoutConstraint.swift
@@ -44,9 +44,21 @@ public class LayoutConstraint : NSLayoutConstraint {
 }
 
 internal func ==(lhs: LayoutConstraint, rhs: LayoutConstraint) -> Bool {
-    guard lhs.firstItem === rhs.firstItem &&
-          lhs.secondItem === rhs.secondItem &&
-          lhs.firstAttribute == rhs.firstAttribute &&
+    // ensure first anchor items match
+    guard let item1 = lhs.firstAnchor.item,
+          let item2 = rhs.firstAnchor.item,
+          item1 === item2 else {
+        return false
+    }
+
+    // ensure second anchor items match
+    guard ((lhs.secondAnchor?.item == nil && rhs.secondAnchor?.item == nil) ||
+           (lhs.secondAnchor?.item === rhs.secondAnchor?.item)) else {
+        return false
+    }
+
+    // ensure attributes, relation, priorty and multiplier match
+    guard lhs.firstAttribute == rhs.firstAttribute &&
           lhs.secondAttribute == rhs.secondAttribute &&
           lhs.relation == rhs.relation &&
           lhs.priority == rhs.priority &&