diff --git a/.travis.yml b/.travis.yml
index 1eba40123..c2ac363d1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,9 +9,9 @@ install:
 script:
 
 # - xcodebuild test -project ./All-Pairs\ Shortest\ Paths/APSP/APSP.xcodeproj -scheme APSPTests
- - xcodebuild test -project ./Array2D/Tests/Tests.xcodeproj -scheme Tests
- - xcodebuild test -project ./AVL\ Tree/Tests/Tests.xcodeproj -scheme Tests
- - xcodebuild test -project ./Binary\ Search/Tests/Tests.xcodeproj -scheme Tests
+- xcodebuild test -project ./Array2D/Tests/Tests.xcodeproj -scheme Tests
+- xcodebuild test -project ./AVL\ Tree/Tests/Tests.xcodeproj -scheme Tests
+- xcodebuild test -project ./Binary\ Search/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Binary\ Search\ Tree/Solution\ 1/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Bloom\ Filter/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Bounded\ Priority\ Queue/Tests/Tests.xcodeproj -scheme Tests
@@ -29,7 +29,7 @@ script:
 # - xcodebuild test -project ./Longest\ Common\ Subsequence/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Minimum\ Spanning\ Tree\ \(Unweighted\)/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Priority\ Queue/Tests/Tests.xcodeproj -scheme Tests
-# - xcodebuild test -project ./Queue/Tests/Tests.xcodeproj -scheme Tests
+ - xcodebuild test -project ./Queue/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Quicksort/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Run-Length\ Encoding/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Select\ Minimum\ Maximum/Tests/Tests.xcodeproj -scheme Tests
@@ -37,5 +37,5 @@ script:
 # - xcodebuild test -project ./Shell\ Sort/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Shortest\ Path\ \(Unweighted\)/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Single-Source\ Shortest\ Paths\ \(Weighted\)/SSSP.xcodeproj -scheme SSSPTests
-# - xcodebuild test -project ./Stack/Tests/Tests.xcodeproj -scheme Tests
+ - xcodebuild test -project ./Stack/Tests/Tests.xcodeproj -scheme Tests
 # - xcodebuild test -project ./Topological\ Sort/Tests/Tests.xcodeproj -scheme Tests
diff --git a/Queue/Queue-Optimized.swift b/Queue/Queue-Optimized.swift
index 5a9d04394..ad6999295 100644
--- a/Queue/Queue-Optimized.swift
+++ b/Queue/Queue-Optimized.swift
@@ -7,8 +7,8 @@
   Enqueuing and dequeuing are O(1) operations.
 */
 public struct Queue<T> {
-  private var array = [T?]()
-  private var head = 0
+  fileprivate var array = [T?]()
+  fileprivate var head = 0
 
   public var isEmpty: Bool {
     return count == 0
@@ -18,7 +18,7 @@ public struct Queue<T> {
     return array.count - head
   }
 
-  public mutating func enqueue(element: T) {
+  public mutating func enqueue(_ element: T) {
     array.append(element)
   }
 
diff --git a/Queue/Queue-Simple.swift b/Queue/Queue-Simple.swift
index 6d3c197ee..27fbdee4d 100644
--- a/Queue/Queue-Simple.swift
+++ b/Queue/Queue-Simple.swift
@@ -8,7 +8,7 @@
   implemented with a linked list, then both would be O(1).
 */
 public struct Queue<T> {
-  private var array = [T]()
+  fileprivate var array = [T]()
 
   public var count: Int {
     return array.count
@@ -18,7 +18,7 @@ public struct Queue<T> {
     return array.isEmpty
   }
 
-  public mutating func enqueue(element: T) {
+  public mutating func enqueue(_ element: T) {
     array.append(element)
   }
 
diff --git a/Queue/Queue.playground/Contents.swift b/Queue/Queue.playground/Contents.swift
index 0c48afd5b..6b771ccd1 100644
--- a/Queue/Queue.playground/Contents.swift
+++ b/Queue/Queue.playground/Contents.swift
@@ -12,7 +12,7 @@
 */
 
 public struct Queue<T> {
-  private var array = [T]()
+  fileprivate var array = [T]()
 
   public var isEmpty: Bool {
     return array.isEmpty
@@ -22,7 +22,7 @@ public struct Queue<T> {
     return array.count
   }
 
-  public mutating func enqueue(element: T) {
+  public mutating func enqueue(_ element: T) {
     array.append(element)
   }
 
diff --git a/Queue/README.markdown b/Queue/README.markdown
index 92118d37b..f7779aa69 100644
--- a/Queue/README.markdown
+++ b/Queue/README.markdown
@@ -46,7 +46,7 @@ Here is a very simplistic implementation of a queue in Swift. It's just a wrappe
 
 ```swift
 public struct Queue<T> {
-  private var array = [T]()
+  fileprivate var array = [T]()
 
   public var isEmpty: Bool {
     return array.isEmpty
@@ -56,7 +56,7 @@ public struct Queue<T> {
     return array.count
   }
 
-  public mutating func enqueue(element: T) {
+  public mutating func enqueue(_ element: T) {
     array.append(element)
   }
   
@@ -136,8 +136,8 @@ Here is how you could implement this version of `Queue`:
 
 ```swift
 public struct Queue<T> {
-  private var array = [T?]()
-  private var head = 0
+  fileprivate var array = [T?]()
+  fileprivate var head = 0
   
   public var isEmpty: Bool {
     return count == 0
@@ -147,7 +147,7 @@ public struct Queue<T> {
     return array.count - head
   }
   
-  public mutating func enqueue(element: T) {
+  public mutating func enqueue(_ element: T) {
     array.append(element)
   }
   
diff --git a/Queue/Tests/Tests.xcodeproj/project.pbxproj b/Queue/Tests/Tests.xcodeproj/project.pbxproj
index ac23063a5..a554fd16e 100644
--- a/Queue/Tests/Tests.xcodeproj/project.pbxproj
+++ b/Queue/Tests/Tests.xcodeproj/project.pbxproj
@@ -83,11 +83,12 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0720;
-				LastUpgradeCheck = 0720;
+				LastUpgradeCheck = 0800;
 				ORGANIZATIONNAME = "Swift Algorithm Club";
 				TargetAttributes = {
 					7B2BBC7F1C779D720067B71D = {
 						CreatedOnToolsVersion = 7.2;
+						LastSwiftMigration = 0800;
 					};
 				};
 			};
@@ -145,8 +146,10 @@
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				CODE_SIGN_IDENTITY = "-";
@@ -189,8 +192,10 @@
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				CODE_SIGN_IDENTITY = "-";
@@ -209,6 +214,7 @@
 				MACOSX_DEPLOYMENT_TARGET = 10.11;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = macosx;
+				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
 			};
 			name = Release;
 		};
@@ -220,6 +226,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = swift.algorithm.club.Tests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 3.0;
 			};
 			name = Debug;
 		};
@@ -231,6 +238,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = swift.algorithm.club.Tests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SWIFT_VERSION = 3.0;
 			};
 			name = Release;
 		};
diff --git a/Queue/Tests/Tests.xcodeproj/xcshareddata/xcschemes/Tests.xcscheme b/Queue/Tests/Tests.xcodeproj/xcshareddata/xcschemes/Tests.xcscheme
index 8ef8d8581..14f27f777 100644
--- a/Queue/Tests/Tests.xcodeproj/xcshareddata/xcschemes/Tests.xcscheme
+++ b/Queue/Tests/Tests.xcodeproj/xcshareddata/xcschemes/Tests.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0720"
+   LastUpgradeVersion = "0800"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"