message: types: make flow happy
diff: @@ -235,8 +235,9 @@ function installComponentHooks (data: VNodeData) {
  }
  }
  -function mergeHook (f1, f2) {
  +function mergeHook (f1: any, f2: any): Function {
  const merged = (a, b) => {
  + // flow complains about extra args which is why we use any
  f1(a, b)
  f2(a, b)
  }
  