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  Note: if the issue is about documentation or the website, please file it at:
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**Do you want to request a *feature* or report a *bug*?**

bug.

**What is the current behavior?**

```js
  renderer.create(
    <Fragment>
      <Fragment>foo</Fragment>
    </Fragment>
  )
  .toTree()
```

> Invariant Violation: toTree() does not yet know how to handle nodes with tag=10

https://codesandbox.io/s/olky92m01y

**What is the expected behavior?**

returns a tree.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**

16.2.0

const array = [];
  let node = nodeWithSibling;
  while (node != null) {
    array.push(node);
    node = node.sibling;
  }
  const trees = array.map(toTree);
  return trees.length ? trees : null;
}
function hasSiblings(node: ?Fiber) {
  return node && node.sibling;
}
function toTree(node: ?Fiber) {
  if (node == null) {
    return null;
  }
  switch (node.tag) {
    case HostRoot: 
      return toTree(node.child);
    case ClassComponent:
      return {
        nodeType: 'component',
        type: node.type,
        props: {...node.memoizedProps},
        instance: node.stateNode,
        rendered: hasSiblings(node.child)
          ? nodeAndSiblingsTrees(node.child)
          : toTree(node.child),
      };