W0102: A live list's items have no key

A loop in a live component's markup makes items with no key. A patch then matches the old and new items by position: removing the first one changes every item after it, and moves their state (focus, what is typed, a nested component's instance) to the wrong row. Reported by vukavet.

Wrong

for _, o := range Orders {
  <li>{o.Ref}</li>
}

Right

for _, o := range Orders {
  <li key={o.ID}>{o.Ref}</li>
}