diff --git a/changelog/upgrade-notes.md b/changelog/upgrade-notes.md
index 86fd03366e..fd31ad4fec 100644
--- a/changelog/upgrade-notes.md
+++ b/changelog/upgrade-notes.md
@@ -4,6 +4,16 @@
 
 #### Backwards incompatible changes
 
+#### Removal of optional this arguments
+
+The optional this (i.e. opt_this) arguments were removed from the following methods.
+Please use closures, the es6 arrow function or the bind method to achieve this effect (Bind is explained here:
+https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind).
+
+* `forEachCorner` in `ol/extent`
+* `LRUCache#forEach`
+* `RBush#forEach` and `RBush#forEachInExtent`
+
 ##### The `setCenter`, `setZoom`, `setResolution` and `setRotation` methods on `ol/View` do not bypass constraints anymore
 
 Previously, these methods allowed setting values that were inconsistent with the given view constraints.
diff --git a/src/ol/TileCache.js b/src/ol/TileCache.js
index 701e48e076..e71cfd4bc3 100644
--- a/src/ol/TileCache.js
+++ b/src/ol/TileCache.js
@@ -44,7 +44,7 @@ class TileCache extends LRUCache {
         this.remove(getKey(tile.tileCoord));
         tile.dispose();
       }
-    }, this);
+    }.bind(this));
   }
 }
 
diff --git a/src/ol/extent.js b/src/ol/extent.js
index 9858190746..cc74b803fb 100644
--- a/src/ol/extent.js
+++ b/src/ol/extent.js
@@ -400,26 +400,25 @@ export function extendXY(extent, x, y) {
  * callback returns a truthy value the function returns that value
  * immediately. Otherwise the function returns `false`.
  * @param {Extent} extent Extent.
- * @param {function(this:T, import("./coordinate.js").Coordinate): S} callback Callback.
- * @param {T=} opt_this Value to use as `this` when executing `callback`.
+ * @param {function(import("./coordinate.js").Coordinate): S} callback Callback.
  * @return {S|boolean} Value.
- * @template S, T
+ * @template S
  */
-export function forEachCorner(extent, callback, opt_this) {
+export function forEachCorner(extent, callback) {
   let val;
-  val = callback.call(opt_this, getBottomLeft(extent));
+  val = callback(getBottomLeft(extent));
   if (val) {
     return val;
   }
-  val = callback.call(opt_this, getBottomRight(extent));
+  val = callback(getBottomRight(extent));
   if (val) {
     return val;
   }
-  val = callback.call(opt_this, getTopRight(extent));
+  val = callback(getTopRight(extent));
   if (val) {
     return val;
   }
-  val = callback.call(opt_this, getTopLeft(extent));
+  val = callback(getTopLeft(extent));
   if (val) {
     return val;
   }
diff --git a/src/ol/geom/Circle.js b/src/ol/geom/Circle.js
index 5b38988a77..7ee4ffab44 100644
--- a/src/ol/geom/Circle.js
+++ b/src/ol/geom/Circle.js
@@ -143,7 +143,7 @@ class Circle extends SimpleGeometry {
         return true;
       }
 
-      return forEachCorner(extent, this.intersectsCoordinate, this);
+      return forEachCorner(extent, this.intersectsCoordinate.bind(this));
     }
     return false;
 
diff --git a/src/ol/source/Vector.js b/src/ol/source/Vector.js
index b4c26b076f..e44191b9fa 100644
--- a/src/ol/source/Vector.js
+++ b/src/ol/source/Vector.js
@@ -485,7 +485,7 @@ class VectorSource extends Source {
       }
     } else {
       if (this.featuresRtree_) {
-        this.featuresRtree_.forEach(this.removeFeatureInternal, this);
+        this.featuresRtree_.forEach(this.removeFeatureInternal.bind(this));
         for (const id in this.nullGeometryFeatures_) {
           this.removeFeatureInternal(this.nullGeometryFeatures_[id]);
         }
diff --git a/src/ol/structs/LRUCache.js b/src/ol/structs/LRUCache.js
index f79ef36baa..29627c6119 100644
--- a/src/ol/structs/LRUCache.js
+++ b/src/ol/structs/LRUCache.js
@@ -96,17 +96,15 @@ class LRUCache extends EventTarget {
 
 
   /**
-   * @param {function(this: S, T, string, LRUCache): ?} f The function
+   * @param {function(T, string, LRUCache): ?} f The function
    *     to call for every entry from the oldest to the newer. This function takes
    *     3 arguments (the entry value, the entry key and the LRUCache object).
    *     The return value is ignored.
-   * @param {S=} opt_this The object to use as `this` in `f`.
-   * @template S
    */
-  forEach(f, opt_this) {
+  forEach(f) {
     let entry = this.oldest_;
     while (entry) {
-      f.call(opt_this, entry.value_, entry.key_, this);
+      f(entry.value_, entry.key_, this);
       entry = entry.newer;
     }
   }
diff --git a/src/ol/structs/RBush.js b/src/ol/structs/RBush.js
index 8d2d8fa6f1..4c0ae6c41b 100644
--- a/src/ol/structs/RBush.js
+++ b/src/ol/structs/RBush.js
@@ -156,41 +156,35 @@ class RBush {
    * Calls a callback function with each value in the tree.
    * If the callback returns a truthy value, this value is returned without
    * checking the rest of the tree.
-   * @param {function(this: S, T): *} callback Callback.
-   * @param {S=} opt_this The object to use as `this` in `callback`.
+   * @param {function(T): *} callback Callback.
    * @return {*} Callback return value.
-   * @template S
    */
-  forEach(callback, opt_this) {
-    return this.forEach_(this.getAll(), callback, opt_this);
+  forEach(callback) {
+    return this.forEach_(this.getAll(), callback);
   }
 
 
   /**
    * Calls a callback function with each value in the provided extent.
    * @param {import("../extent.js").Extent} extent Extent.
-   * @param {function(this: S, T): *} callback Callback.
-   * @param {S=} opt_this The object to use as `this` in `callback`.
+   * @param {function(T): *} callback Callback.
    * @return {*} Callback return value.
-   * @template S
    */
-  forEachInExtent(extent, callback, opt_this) {
-    return this.forEach_(this.getInExtent(extent), callback, opt_this);
+  forEachInExtent(extent, callback) {
+    return this.forEach_(this.getInExtent(extent), callback);
   }
 
 
   /**
    * @param {Array<T>} values Values.
-   * @param {function(this: S, T): *} callback Callback.
-   * @param {S=} opt_this The object to use as `this` in `callback`.
+   * @param {function(T): *} callback Callback.
    * @private
    * @return {*} Callback return value.
-   * @template S
    */
-  forEach_(values, callback, opt_this) {
+  forEach_(values, callback) {
     let result;
     for (let i = 0, l = values.length; i < l; i++) {
-      result = callback.call(opt_this, values[i]);
+      result = callback(values[i]);
       if (result) {
         return result;
       }
diff --git a/test/spec/ol/extent.test.js b/test/spec/ol/extent.test.js
index e0984eb4b9..eb59120a2e 100644
--- a/test/spec/ol/extent.test.js
+++ b/test/spec/ol/extent.test.js
@@ -239,13 +239,6 @@ describe('ol.extent', function() {
       }
     );
 
-    it('calls the callback with given scope', function() {
-      const extent = [1, 2, 3, 4];
-      const scope = {humpty: 'dumpty'};
-      _ol_extent_.forEachCorner(extent, callbackTrue, scope);
-      expect(callbackTrue.calledOn(scope)).to.be(true);
-    });
-
   });
 
   describe('getArea', function() {