diff --git a/prelude-ls/prelude-ls-tests.ts b/prelude-ls/prelude-ls-tests.ts
index b6e50e225..8c37a1e71 100644
--- a/prelude-ls/prelude-ls-tests.ts
+++ b/prelude-ls/prelude-ls-tests.ts
@@ -1,23 +1,27 @@
+/// <reference path="./prelude-ls.d.ts" />
+
 import prelude = require("prelude-ls");
 
-prelude.id(5);  //=> 5
-prelude.id({}); //=> {}
+var five: number = prelude.id(5);  //=> 5
+var emptyObj: Object = prelude.id({}); //=> {}
 
-prelude.isType("Undefined", void 8); //=> true
+var expectBool: boolean = prelude.isType("Undefined", void 8); //=> true
 prelude.isType("Boolean", true);     //=> true
 prelude.isType("Number", 1);         //=> true
 prelude.isType("String", "hi");      //=> true
 prelude.isType("Object", {});        //=> true
 prelude.isType("Array", []);         //=> true
 
-prelude.replicate(4, 3);   //=> [3, 3, 3, 3]
-prelude.replicate(4, "a"); //=> ["a", "a", "a", "a"]
+var numberArray: Array<number> = prelude.replicate(4, 3);   //=> [3, 3, 3, 3]
+var strArray: Array<string> =
+  prelude.replicate(4, "a"); //=> ["a", "a", "a", "a"]
 prelude.replicate(0, "a"); //=> []
 
 
 // List
 
-prelude.each(x => x.push("boom"), [["a"], ["b"], ["c"]]);
+var dblStrArray: Array<Array<string>> =
+  prelude.each(x => x.push("boom"), [["a"], ["b"], ["c"]]);
 //=> [["a", "boom"], ["b", "boom"], ["c", "boom"]]
 
 prelude.map(x => x * 2, [1, 2, 3, 4, 5]);         //=> [2, 4, 6, 8, 10]
diff --git a/prelude-ls/prelude-ls.d.ts b/prelude-ls/prelude-ls.d.ts
index 848077c82..0de28f63a 100644
--- a/prelude-ls/prelude-ls.d.ts
+++ b/prelude-ls/prelude-ls.d.ts
@@ -3,6 +3,8 @@
 // Definitions by: Aya Morisawa <https://github.com/AyaMorisawa>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
+// Change [0]: 2015/06/14 - Marcelo Camargo <https://github.com/haskellcamargo>
+
 declare module "prelude-ls" {
 	module PreludeLS {
 		export function id<A>(x: A): A;
@@ -14,8 +16,8 @@ declare module "prelude-ls" {
 		
 		// List
 		
-		export function each<A>(f: (x: A) => void): (xs: A[]) => void;
-		export function each<A>(f: (x: A) => void, xs: A[]): void;
+		export function each<A>(f: (x: A) => void): (xs: A[]) => A[];
+		export function each<A>(f: (x: A) => void, xs: A[]): A[];
 		export function map<A, B>(f: (x: A) => B): (xs: A[]) => B[];
 		export function map<A, B>(f: (x: A) => B, xs: A[]): B[];
 		export function compact<A>(xs: A[]): A[];