I was wondering when we'll get three-index slices

From the text: "It is impossible to use this new slice value to access the last three elements of the original array"

Shouldn't this rather be: "It is impossible to use this new slice value to access the last element of the original array"

It looks like the third number specifies an index, not a length.

  var array [10]int
  slice = array[2:4:7]

> its capacity is now only 5 elements (7-2)

Built-in test coverage, nice.