类型[] int没有字段或方法长度

I have the following code -

package "main"

var fibonacciNumbers = []int{0, 1}

func getIthFibo(i int) int {
    if i < fibonacciNumbers.length {
        return fibonacciNumbers[i]
    }
    ...
}

However, I get an error at the if condition -

fibonacciNumbers.length undefined - type []int has no field or method length

What I understood was that I created a slice with the elements 0 and 1 - so it should have a length of 2 but I get the above error.

The golang way of getting a slices length is to use the len function:

if i < len(fibonacciNumbers)