diff --git a/jquery/jquery-tests.ts b/jquery/jquery-tests.ts
index 01f75a9855..4fb31f0ed2 100644
--- a/jquery/jquery-tests.ts
+++ b/jquery/jquery-tests.ts
@@ -2294,4 +2294,11 @@ function test_EventIsNewable() {
 
 function test_EventIsCallable() {
     var ev = jQuery.Event('click');
-}
\ No newline at end of file
+}
+
+$.when($.ajax("/my/page.json")).then((a,b,c) => a.asdf); // is type JQueryPromise<any>
+$.when("asdf", "jkl;").done(x => x.length, x=> x.length);
+
+var f1 = $.when("fetch"); // Is type JQueryPromise<string>
+var f2: JQueryPromise<string[]> = f1.then(s => [s, s]);
+var f3: JQueryPromise<number> = f2.then(v => 3);
diff --git a/jquery/jquery.d.ts b/jquery/jquery.d.ts
index c2f9f47ddb..57dfff6be4 100644
--- a/jquery/jquery.d.ts
+++ b/jquery/jquery.d.ts
@@ -105,11 +105,11 @@ interface JQueryPromise<T> {
     then<U>(onFulfill: (value: T) => U, onReject?: (...reasons) => JQueryGenericPromise<U>, onProgress?: (...progression) => any): JQueryPromise<U>;
     then<U>(onFulfill: (value: T) => JQueryGenericPromise<U>, onReject?: (...reasons) => JQueryGenericPromise<U>, onProgress?: (...progression) => any): JQueryPromise<U>;
 
-    /* Because JQuery Promises Suck */
-    then<U>(onFulfill: (...args) => U, onReject?: (...reasons) => U, onProgress?: (...progression) => any): JQueryPromise<U>;
-    then<U>(onFulfill: (...args) => JQueryGenericPromise<U>, onReject?: (...reasons) => U, onProgress?: (...progression) => any): JQueryPromise<U>;
-    then<U>(onFulfill: (...args) => U, onReject?: (...reasons) => JQueryGenericPromise<U>, onProgress?: (...progression) => any): JQueryPromise<U>;
-    then<U>(onFulfill: (...args) => JQueryGenericPromise<U>, onReject?: (...reasons) => JQueryGenericPromise<U>, onProgress?: (...progression) => any): JQueryPromise<U>;
+    // Because JQuery Promises Suck
+    then<U>(onFulfill: (...values) => U, onReject?: (...reasons) => U, onProgress?: (...progression) => any): JQueryPromise<U>;
+	then<U>(onFulfill: (...values) => JQueryGenericPromise<U>, onReject?: (...reasons) => U, onProgress?: (...progression) => any): JQueryPromise<U>;
+	then<U>(onFulfill: (...values) => U, onReject?: (...reasons) => JQueryGenericPromise<U>, onProgress?: (...progression) => any): JQueryPromise<U>;
+	then<U>(onFulfill: (...values) => JQueryGenericPromise<U>, onReject?: (...reasons) => JQueryGenericPromise<U>, onProgress?: (...progression) => any): JQueryPromise<U>;
 }
 
 /*
@@ -265,7 +265,9 @@ interface JQueryStatic {
 
     noConflict(removeAll?: boolean): Object;
 
-    when(...deferreds: any[]): JQueryPromise;
+	when<T>(...deferreds: JQueryGenericPromise<T>[]): JQueryPromise<T>;
+	when<T>(...deferreds: T[]): JQueryPromise<T>;
+	when<T>(...deferreds: any[]): JQueryPromise<T>;
 
     // CSS
     css(e: any, propertyName: string, value?: any);
diff --git a/mocha/mocha.d.ts b/mocha/mocha.d.ts
index 572edbc71f..50fb3fcc47 100644
--- a/mocha/mocha.d.ts
+++ b/mocha/mocha.d.ts
@@ -12,27 +12,27 @@ declare var describe : {
 
 declare var it: {
     (expectation: string, assertion?: () => void): void;
-    (expectation: string, assertion?: (done: () => void) => void): void;
+    (expectation: string, assertion?: (done: (failReason?) => void) => void): void;
     only(expectation: string, assertion?: () => void): void;
-    only(expectation: string, assertion?: (done: () => void) => void): void;
+	only(expectation: string, assertion?: (done: (failReason?) => void) => void): void;
     skip(expectation: string, assertion?: () => void): void;
-    skip(expectation: string, assertion?: (done: () => void) => void): void;
+	skip(expectation: string, assertion?: (done: (failReason?) => void) => void): void;
     timeout(ms: number);
 };
 
 declare function before(action: () => void): void;
 
-declare function before(action: (done: () => void) => void): void;
+declare function before(action: (done: (failReason?) => void) => void): void;
 
 declare function after(action: () => void): void;
 
-declare function after(action: (done: () => void) => void): void;
+declare function after(action: (done: (failReason?) => void) => void): void;
 
 declare function beforeEach(action: () => void): void;
 
-declare function beforeEach(action: (done: () => void) => void): void;
+declare function beforeEach(action: (done: (failReason?) => void) => void): void;
 
 declare function afterEach(action: () => void): void;
 
-declare function afterEach(action: (done: () => void) => void): void;
+declare function afterEach(action: (done: (failReason?) => void) => void): void;