Occurs in Fiber with multiple instances of the React package (which can't share current owner).
* Copyright 2013-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule ReactChildFiber
 * @flow
 */
'use strict';
import type {ReactElement} from 'ReactElementType';
import type {ReactCoroutine, ReactPortal, ReactYield} from 'ReactTypes';
import type {Fiber} from 'ReactFiber';
import type {ReactInstance} from 'ReactInstanceType';
import type {PriorityLevel} from 'ReactPriorityLevel';
var {REACT_COROUTINE_TYPE, REACT_YIELD_TYPE} = require('ReactCoroutine');
var {REACT_PORTAL_TYPE} = require('ReactPortal');
var ReactFiber = require('ReactFiber');
var ReactTypeOfSideEffect = require('ReactTypeOfSideEffect');
var ReactTypeOfWork = require('ReactTypeOfWork');
var emptyObject = require('fbjs/lib/emptyObject');
var invariant = require('fbjs/lib/invariant');
var ReactFeatureFlags = require('ReactFeatureFlags');
if (__DEV__) {
  var {getCurrentFiberStackAddendum} = require('ReactDebugCurrentFiber');
  var warning = require('fbjs/lib/warning');
  var didWarnAboutMaps = false;
  /**
   * Warn if there's no key explicitly set on dynamic arrays of children or