diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 8d2f01f3de27a..550e2c90e1244 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -1400,8 +1400,8 @@ namespace ts {
     /** Shims `Array.from`. */
     export function arrayFrom<T, U>(iterator: Iterator<T> | IterableIterator<T>, map: (t: T) => U): U[];
     export function arrayFrom<T>(iterator: Iterator<T> | IterableIterator<T>): T[];
-    export function arrayFrom(iterator: Iterator<any> | IterableIterator<any>, map?: (t: any) => any): any[] {
-        const result: any[] = [];
+    export function arrayFrom<T, U>(iterator: Iterator<T> | IterableIterator<T>, map?: (t: T) => U): (T | U)[] {
+        const result: (T | U)[] = [];
         for (let { value, done } = iterator.next(); !done; { value, done } = iterator.next()) {
             result.push(map ? map(value) : value);
         }