Originally discovered by a post on the forum, you can do this today:

type baseProps = {"name": string}

type props = {
  ...baseProps,
  label: string,
}

let label: props = {
  "name": "hello",
  "label": "label",
}

See playground

The compiler would not complain (tested with versions v11.0.0 to v11.1.1), type props here looks like a record type but is actually an object type.