message: tweak noramlizeArrayChildren
diff: @@ -36,6 +36,10 @@ export function normalizeChildren (children: any): ?Array<VNode> {
  : undefined
  }
  +function isTextNode (node): boolean {
  + return isDef(node) && isDef(node.text) && isFalse(node.isComment)
  +}
  +
  function normalizeArrayChildren (children: any, nestedIndex?: string): Array<VNode> {
  const res = []
  let i, c, last
  @@ -47,14 +51,14 @@ function normalizeArrayChildren (children: any, nestedIndex?: string): Array<VNo
  if (Array.isArray(c)) {
  res.push.apply(res, normalizeArrayChildren(c, `${nestedIndex || ''}_${i}`))
  } else if (isPrimitive(c)) {
  - if (isDef(last) && isDef(last.text)) {
  - last.text += String(c)
  + if (isTextNode(last)) {
  + (last: any).text += String(c)
  } else if (c !== '') {
  // convert primitive to vnode
  res.push(createTextVNode(c))
  }
  } else {
  - if (isFalse(c.isComment) && isDef(c.text) && isDef(last) && isFalse(last.isComment) && isDef(last.text)) {
  + if (isTextNode(c) && isTextNode(last)) {
  res[res.length - 1] = createTextVNode(last.text + c.text)
  } else {
  // default key for nested array children (likely generated by v-for)
  