Function coerceRef

packages/react-reconciler/src/ReactChildFiber.js:287–295

(workInProgress: Fiber, element: ReactElement)

}

function coerceRef(workInProgress: Fiber, element: ReactElement): void {
  // TODO: This is a temporary, intermediate step. Now that enableRefAsProp is on,
  // we should resolve the `ref` prop during the begin phase of the component
  // it's attached to (HostComponent, ClassComponent, etc).
  const refProp = element.props.ref;
  // TODO: With enableRefAsProp now rolled out, we shouldn't use the `ref` field. We
  // should always read the ref from the prop.
  workInProgress.ref = refProp !== undefined ? refProp : null;
}

function throwOnInvalidObjectTypeImpl(returnFiber: Fiber, newChild: Object) {
  if (newChild.$$typeof === REACT_LEGACY_ELEMENT_TYPE) {