fix(overlay): attempting to position overlay if it was detached immediately after being attached

src/cdk/overlay/overlay-ref.ts

@@ -82,7 +82,10 @@ export class OverlayRef implements PortalOutlet {
     // before attempting to position it, as the position may depend on the size of the rendered
     // content.
     this._ngZone.onStable.asObservable().pipe(take(1)).subscribe(() => {
-      this.updatePosition();
+      // The overlay could've been detached before the zone has stabilized.
+      if (this.hasAttached()) {
+        this.updatePosition();
+      }
     });
 
     // Enable pointer events for the overlay pane element.

src/cdk/overlay/overlay.spec.ts

@@ -255,6 +255,22 @@ describe('Overlay', () => {
 
       expect(overlayContainerElement.querySelectorAll('.fake-positioned').length).toBe(1);
     }));
+
+    it('should not apply the position if it detaches before the zone stabilizes', fakeAsync(() => {
+      config.positionStrategy = new FakePositionStrategy();
+
+      const overlayRef = overlay.create(config);
+
+      spyOn(config.positionStrategy, 'apply');
+
+      overlayRef.attach(componentPortal);
+      overlayRef.detach();
+      viewContainerFixture.detectChanges();
+      tick();
+
+      expect(config.positionStrategy.apply).not.toHaveBeenCalled();
+    }));
+
   });
 
   describe('size', () => {