Combine Mending items on Anvil

The Mending Enchantment is one of the most rarest enchantments to currently get in the game. When I was doing AFK fishing, I received two treasure items (bow and fishing rod) with mending and I wanted to fuse them together with my current bow and fishing rod ASAP. When I used the anvil, and combined the two, the mending enchantment did not transferred over to the new item. So in the end, all I ended up doing was repairing my tools rather than receiving any new enchantments. Please fix this issue.