mozilla/rust — pull request #14272 by kballard (2014-05-18 04:05:15+00:00)
Title: Add syntax extension ary![expr, ..N]

`ary![expr, ..N]` expands to an array by repeating `expr` N times. This is
in contrast to `[expr, ..N]` which Copies `expr` N times.

Sample usage:

let x = ary![None::>, ..10];

The one limitation is the count needs to be an integral literal, it
cannot be a static or a compile-time expression.