diff --git a/src/observable/list/BaseObservableList.ts b/src/observable/list/BaseObservableList.ts
index 6d8bd1af..d103eb64 100644
--- a/src/observable/list/BaseObservableList.ts
+++ b/src/observable/list/BaseObservableList.ts
@@ -35,7 +35,7 @@ export function defaultObserverWith<T>(overrides: { [key in keyof IListObserver<
     return Object.assign(defaults, overrides);
 }
 
-export abstract class BaseObservableList<T> extends BaseObservable<IListObserver<T>> {
+export abstract class BaseObservableList<T> extends BaseObservable<IListObserver<T>> implements Iterable<T> {
     emitReset() {
         for(let h of this._handlers) {
             h.onReset(this);
@@ -69,6 +69,6 @@ export abstract class BaseObservableList<T> extends BaseObservable<IListObserver
         }
     }
 
-    abstract [Symbol.iterator]();
+    abstract [Symbol.iterator](): Iterator<T>;
     abstract get length(): number;
 }
diff --git a/src/platform/web/ui/general/Range.ts b/src/platform/web/ui/general/Range.ts
index 16dc0a33..a3ca54c0 100644
--- a/src/platform/web/ui/general/Range.ts
+++ b/src/platform/web/ui/general/Range.ts
@@ -43,7 +43,7 @@ export class Range {
         return range.start < this.end && this.start < range.end;
     }
 
-    forEachInIterator<T>(it: IterableIterator<T>, callback: ((T, i: number) => void)) {
+    forEachInIterator<T>(it: Iterator<T>, callback: ((T, i: number) => void)) {
         let i = 0;
         for (i = 0; i < this.start; i += 1) {
             it.next();