Changing ContentChildren models on QueryList.changes

Suppose I have a parent component with @ContentChildren(Child) children. Suppose that each Child has an index field within its component class. I'd like to keep these index fields up-to-date when the parent's children change, doing something as follows:

this.children.changes.subscribe(() => {
  this.children.forEach((child, index) => {
    child.index = index;
  })
});

However, when I attempt to do this, I get an "ExpressionChangedAfter..." error, I guess due to the fact that this index update is occurring outside of a change cycle. Here's a stackblitz demonstrating this error: https://stackblitz.com/edit/angular-brjjrl.

How can I work around this? One obvious way is to simply bind the index in the template. A second obvious way is to just call detectChanges() for each child when you update its index. Suppose I can't do either of these approaches, is there another approach?

from Changing ContentChildren models on QueryList.changes