diff --git a/KVConstraintKit/KVConstraintKit.swift b/KVConstraintKit/KVConstraintKit.swift
index 48762f7..59c301d 100644
--- a/KVConstraintKit/KVConstraintKit.swift
+++ b/KVConstraintKit/KVConstraintKit.swift
@@ -37,7 +37,9 @@
     
     public typealias View = NSView
     public typealias LayoutPriority = NSLayoutPriority
-    public typealias EdgeInsets = NSEdgeInsets
+    #if !swift(>=3.0)
+        public typealias EdgeInsets = NSEdgeInsets
+    #endif
 #endif
 
 extension EdgeInsets {
@@ -106,7 +108,7 @@ extension View {
             
         #else
             switch attr1 {
-            case .Right, .Trailing, .Bottom:
+            case .right, .trailing, .bottom:
                 return View.prepareConstraint(superview, attribute: attr1, secondView: self, attribute:attr2, relation: relation, multiplier:multiplier)
             default: break
             }
diff --git a/KVConstraintKit/KVConstraintKitOperators.swift b/KVConstraintKit/KVConstraintKitOperators.swift
index 1e71f0d..4c8d5c3 100644
--- a/KVConstraintKit/KVConstraintKitOperators.swift
+++ b/KVConstraintKit/KVConstraintKitOperators.swift
@@ -239,12 +239,24 @@ extension View : Modifiable { }
 
 /// (containerView ~ (constraint, multiplier))
 public func *(lhs: View, rhs: (NSLayoutConstraint, CGFloat)) {
-    (lhs ~ (rhs.0, rhs.0.modified(multiplier: rhs.1)))
+    #if os(iOS) || os(tvOS)
+        let constraint = rhs.0.modified(multiplier: rhs.1)
+    #else
+        guard let constraint = rhs.0.modified(multiplier: rhs.1) else { return  }
+    #endif
+    
+    (lhs ~ (rhs.0, constraint))
+
 }
 
 /// (containerView ~ (constraint, multiplier))
 public func ~(lhs: View, rhs: (NSLayoutConstraint, NSLayoutRelation)) {
-    (lhs ~ (rhs.0, rhs.0.modified(relation: rhs.1)))
+    #if os(iOS) || os(tvOS)
+        let constraint = rhs.0.modified(relation: rhs.1)
+    #else
+        guard let constraint = rhs.0.modified(relation: rhs.1) else { return  }
+    #endif
+    (lhs ~ (rhs.0, constraint))
 }
 
 /// (containerView ~ (old, new))
diff --git a/KVConstraintKit/NSLayoutConstraintExtension.swift b/KVConstraintKit/NSLayoutConstraintExtension.swift
index 730313b..eef0ad4 100644
--- a/KVConstraintKit/NSLayoutConstraintExtension.swift
+++ b/KVConstraintKit/NSLayoutConstraintExtension.swift
@@ -96,24 +96,48 @@ extension NSLayoutConstraint
         
     }
     
+#if os(iOS) || os(tvOS)
+
     public final func modified(relation r: NSLayoutRelation) -> NSLayoutConstraint
     {
         if relation == r {
             return self
         }
-        
         return NSLayoutConstraint(item: firstItem, attribute: firstAttribute, relatedBy: r, toItem: secondItem, attribute: secondAttribute, multiplier: multiplier, constant: constant)
     }
-    
+
     public final func modified(multiplier m: CGFloat) -> NSLayoutConstraint
     {
         if multiplier == m {
             return self
         }
-        
         return NSLayoutConstraint(item: firstItem, attribute: firstAttribute, relatedBy: relation, toItem: secondItem, attribute: secondAttribute, multiplier: m, constant: constant)
     }
     
+#else
+
+    public final func modified(relation r: NSLayoutRelation) -> NSLayoutConstraint?
+    {
+        if relation == r {
+            return self
+        }
+        guard let firstItem = self.firstItem else { return nil }
+        return NSLayoutConstraint(item: firstItem, attribute: firstAttribute, relatedBy: r, toItem: secondItem, attribute: secondAttribute, multiplier: multiplier, constant: constant)
+    }
+
+    public final func modified(multiplier m: CGFloat) -> NSLayoutConstraint?
+    {
+        if multiplier == m {
+            return self
+        }
+        guard let firstItem = self.firstItem else { return nil }
+        return NSLayoutConstraint(item: firstItem, attribute: firstAttribute, relatedBy: relation, toItem: secondItem, attribute: secondAttribute, multiplier: m, constant: constant)
+    }
+    
+#endif
+
+    
+   
     final func isSelfConstraint() -> Bool
     {
         // For aspect Ratio
@@ -139,7 +163,7 @@ extension Array where Element: NSLayoutConstraint
                 !( $0.firstItem is UILayoutSupport || $0.secondItem is UILayoutSupport)
             }
         #else
-            let reverseConstraints = reverse()
+            let reverseConstraints = reversed()
         #endif
         
         return reverseConstraints.filter {