Reusing Shorthand in the Same Block in Go

Sometimes one statement needs to create a new variable and update an existing one. Go allows := to do both in the same block but at least one name on the left must be new and the existing variable must keep its type in The Golang Official Documentation

package main
 
func main() {
	count := 10
	count, limit := 20, 30
	fmt.Println(count, limit)
}

If you’ll run this with go run main.go, you’ll get 20 30

In count, limit := 20, 30, count already exists and limit does not. Go assigns 20 to the existing count and declares limit with the value 30`

Now if you’ll remove limit and try to declare only count again, you’ll get a compiler error