diff --git a/src/ol/base/collection.js b/src/ol/base/collection.js
index 310d426d96..bd151d3d1e 100644
--- a/src/ol/base/collection.js
+++ b/src/ol/base/collection.js
@@ -104,9 +104,8 @@ ol.Collection.prototype.clear = function() {
 
 
 /**
- * @param {function(this: T, *, number)} f Function.
- * @param {T=} opt_obj The object to be used for the value of 'this' within f.
- * @template T
+ * @param {Function} f Function.
+ * @param {Object=} opt_obj Object.
  */
 ol.Collection.prototype.forEach = function(f, opt_obj) {
   goog.array.forEach(this.array_, f, opt_obj);