ICE in universal_regions.rs when compiling bitflags using NLL

[est31]

Clone https://github.com/rust-lang-nursery/bitflags and trying to compile it with NLL enabled gives you an ICE:

$ RUSTFLAGS="-Zborrowck=mir -Z nll" cargo build
error: internal compiler error: /checkout/src/librustc_mir/borrow_check/nll/universal_regions.rs:496: impossible case reached

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.24.0-nightly (6a3601944 2017-12-12) running on x86_64-unknown-linux-gnu

thread 'rustc' panicked at 'Box<Any>', /checkout/src/librustc_errors/lib.rs:501:8
note: Run with `RUST_BACKTRACE=1` for a backtrace.

error: Could not compile `bitflags`.

To learn more, run the command again with --verbose.

Minimized testcase:

pub struct Foo;
pub const FOO: Foo = Foo;

[est31]

@nikomatsakis is this a dupe of #46702 ? If so please close :)

[sapphire-arches]

I'm not sure if this is a dupe, but it appears to be fixed on nightly now, so I'm going to close this issue.