eth/fetcher: reuse variables for hash and number (#16819)

eth/fetcher/fetcher.go

@@ -292,20 +292,20 @@ func (f *Fetcher) loop() {
  height := f.chainHeight()
  for !f.queue.Empty() {
  op := f.queue.PopItem().(*inject)
+ hash := op.block.Hash()
  if f.queueChangeHook != nil {
- f.queueChangeHook(op.block.Hash(), false)
+ f.queueChangeHook(hash, false)
  }
  // If too high up the chain or phase, continue later
  number := op.block.NumberU64()
  if number > height+1 {
- f.queue.Push(op, -float32(op.block.NumberU64()))
+ f.queue.Push(op, -float32(number))
  if f.queueChangeHook != nil {
- f.queueChangeHook(op.block.Hash(), true)
+ f.queueChangeHook(hash, true)
  }
  break
  }
  // Otherwise if fresh and still unknown, try and import
- hash := op.block.Hash()
  if number+maxUncleDist < height || f.getBlock(hash) != nil {
  f.forgetBlock(hash)
  continue