diff --git a/CoreStore/Fetching and Querying/BaseDataTransaction+Querying.swift b/CoreStore/Fetching and Querying/BaseDataTransaction+Querying.swift
index 4f2cd25..f199328 100644
--- a/CoreStore/Fetching and Querying/BaseDataTransaction+Querying.swift	
+++ b/CoreStore/Fetching and Querying/BaseDataTransaction+Querying.swift	
@@ -80,12 +80,10 @@ public extension BaseDataTransaction {
         var existingObjects = [T]()
         for object in objects {
             
-            do {
+            if let existingObject = (try? self.context.existingObjectWithID(object.objectID)) as? T {
                 
-                let existingObject = try self.context.existingObjectWithID(object.objectID) as! T
                 existingObjects.append(existingObject)
             }
-            catch _ { }
         }
         return existingObjects
     }
@@ -101,12 +99,10 @@ public extension BaseDataTransaction {
         var existingObjects = [T]()
         for objectID in objectIDs {
             
-            do {
+            if let existingObject = (try? self.context.existingObjectWithID(objectID)) as? T {
                 
-                let existingObject = try self.context.existingObjectWithID(objectID) as! T
                 existingObjects.append(existingObject)
             }
-            catch _ { }
         }
         return existingObjects
     }
diff --git a/CoreStore/Fetching and Querying/DataStack+Querying.swift b/CoreStore/Fetching and Querying/DataStack+Querying.swift
index cdec5fd..601f4b1 100644
--- a/CoreStore/Fetching and Querying/DataStack+Querying.swift	
+++ b/CoreStore/Fetching and Querying/DataStack+Querying.swift	
@@ -81,12 +81,10 @@ public extension DataStack {
         var existingObjects = [T]()
         for object in objects {
             
-            do {
+            if let existingObject = (try? self.mainContext.existingObjectWithID(object.objectID)) as? T {
                 
-                let existingObject = try self.mainContext.existingObjectWithID(object.objectID) as! T
                 existingObjects.append(existingObject)
             }
-            catch _ { }
         }
         return existingObjects
     }
@@ -102,12 +100,10 @@ public extension DataStack {
         var existingObjects = [T]()
         for objectID in objectIDs {
             
-            do {
+            if let existingObject = (try? self.mainContext.existingObjectWithID(objectID)) as? T {
                 
-                let existingObject = try self.mainContext.existingObjectWithID(objectID) as! T
                 existingObjects.append(existingObject)
             }
-            catch _ { }
         }
         return existingObjects
     }
diff --git a/CoreStore/Importing Data/BaseDataTransaction+Importing.swift b/CoreStore/Importing Data/BaseDataTransaction+Importing.swift
index 4fdfe7b..991628d 100644
--- a/CoreStore/Importing Data/BaseDataTransaction+Importing.swift	
+++ b/CoreStore/Importing Data/BaseDataTransaction+Importing.swift	
@@ -201,7 +201,7 @@ public extension BaseDataTransaction {
                     }
                 }
                 
-                for object in self.fetchAll(From(T), Where("%K IN %@", T.uniqueIDKeyPath, mapping.keys.array)) ?? [] {
+                for object in self.fetchAll(From(T), Where("%K IN %@", T.uniqueIDKeyPath, Array(mapping.keys))) ?? [] {
                     
                     try autoreleasepool {
                         
@@ -261,7 +261,7 @@ public extension BaseDataTransaction {
                 }
                 
                 var objects = Dictionary<T.UniqueIDType, T>()
-                for object in self.fetchAll(From(T), Where("%K IN %@", T.uniqueIDKeyPath, mapping.keys.array)) ?? [] {
+                for object in self.fetchAll(From(T), Where("%K IN %@", T.uniqueIDKeyPath, Array(mapping.keys))) ?? [] {
                     
                     try autoreleasepool {
                         
diff --git a/CoreStore/Migrating/DataStack+Migration.swift b/CoreStore/Migrating/DataStack+Migration.swift
index f1720f3..af7c05e 100644
--- a/CoreStore/Migrating/DataStack+Migration.swift
+++ b/CoreStore/Migrating/DataStack+Migration.swift
@@ -436,7 +436,7 @@ public extension DataStack {
         
         let migrationOperation = NSBlockOperation()
         migrationOperation.qualityOfService = .Utility
-        operations.map { migrationOperation.addDependency($0) }
+        operations.forEach { migrationOperation.addDependency($0) }
         migrationOperation.addExecutionBlock { () -> Void in
             
             GCDQueue.Main.async {
diff --git a/CoreStore/Migrating/MigrationChain.swift b/CoreStore/Migrating/MigrationChain.swift
index 784c579..79ee8c0 100644
--- a/CoreStore/Migrating/MigrationChain.swift
+++ b/CoreStore/Migrating/MigrationChain.swift
@@ -237,9 +237,9 @@ extension MigrationChain: CustomDebugStringConvertible {
                 steps.append(nextVersion)
                 version = nextVersion
             }
-            paths.append(" → ".join(steps))
+            paths.append(steps.joinWithSeparator(" → "))
         }
         
-        return "[" + "], [".join(paths) + "]"
+        return "[" + paths.joinWithSeparator("], [") + "]"
     }
 }
diff --git a/CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift b/CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift
index 5c4908c..2cb76ec 100644
--- a/CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift	
+++ b/CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift	
@@ -285,7 +285,7 @@ class MigrationsDemoViewController: UIViewController {
         }
         
         self.titleLabel?.text = organismType
-        self.organismLabel?.text = "\n".join(lines)
+        self.organismLabel?.text = lines.joinWithSeparator("\n")
         self.progressView?.progress = 0
         
         self.headerContainer?.setNeedsLayout()
diff --git a/CoreStoreTests/CoreStoreTests.swift b/CoreStoreTests/CoreStoreTests.swift
index 423b7d3..81bc2a2 100644
--- a/CoreStoreTests/CoreStoreTests.swift
+++ b/CoreStoreTests/CoreStoreTests.swift
@@ -377,8 +377,9 @@ class CoreStoreTests: XCTestCase {
         
         do {
             
-            try NSFileManager.defaultManager().removeItemAtURL(
-                NSFileManager.defaultManager().URLsForDirectory(.ApplicationSupportDirectory, inDomains: .UserDomainMask).first!
+            let fileManager = NSFileManager.defaultManager()
+            try fileManager.removeItemAtURL(
+                fileManager.URLsForDirectory(.ApplicationSupportDirectory, inDomains: .UserDomainMask).first!
             )
         }
         catch _ { }