From ddf15594fdd565a5909127a9d88e300342cc3e8f Mon Sep 17 00:00:00 2001
From: Robert Payne <robertpayne@me.com>
Date: Wed, 23 Nov 2016 15:28:35 +1300
Subject: [PATCH] Improve looping of existing constraints

---
 Source/Constraint.swift | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Source/Constraint.swift b/Source/Constraint.swift
index c4df105..3c2c242 100644
--- a/Source/Constraint.swift
+++ b/Source/Constraint.swift
@@ -252,11 +252,15 @@ public class Constraint {
             return
         }
         let layoutConstraints = self.layoutConstraints
-        let existingLayoutConstraints = item.constraints.map({ $0.layoutConstraints }).reduce([]) { $0 + $1 }
         
         if updatingExisting {
+            var existingLayoutConstraints: [LayoutConstraint] = []
+            for constraint in item.constraints {
+                existingLayoutConstraints += constraint.layoutConstraints
+            }
+            
             for layoutConstraint in layoutConstraints {
-                let existingLayoutConstraint = existingLayoutConstraints.first { $0 == layoutConstraint }
+                let existingLayoutConstraint = existingLayoutConstraints.first { $0.canUpdate(constraint: layoutConstraint) }
                 guard let updateLayoutConstraint = existingLayoutConstraint else {
                     fatalError("Updated constraint could not find existing matching constraint to update: \(layoutConstraint)")
                 }