Those that follow Rust nightlies know that they've been produced rarely this month due to various breakage. Last night's build finally succeed and you can install rustc 1.16.0-nightly (4ecc85beb 2016-12-28)
now.
The interruption in nightly service is regrettable, but there are plans underway to make nightlies more reliably-produced in the future, described yon.