ICE (cannot relate bound region) with universally-quantified closure lifetime bound

[arielb1]

The following code:

#![feature(lang_items)]
#![no_std]
#![crate_type="rlib"]
#[lang="sized"] pub trait Sized for Sized? {}

fn ice(f: for<'s> ||:'s) {}
fn main() { ice(||{}) }

causes the following ICE:

panic.rs:7:17: 7:21 error: internal compiler error: cannot relate bound region: ReLateBound(7, BrNamed(DefId { krate: 0, node: 10 }, 's)) <= '_#0r
panic.rs:7 fn main() { ice(||{}) }
                           ^~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
task 'rustc' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/libsyntax/diagnostic.rs:116

stack backtrace:
   1:     0x7f2de2506880 - rt::backtrace::imp::write::hcdc2f7be6d055c99Pdt
   2:     0x7f2de2509700 - failure::on_fail::h5788810ad30506feqzt
   3:     0x7f2de25250d0 - unwind::begin_unwind_inner::h95fceca7f7fff8e4E9c
   4:     0x7f2de1486ba0 - unwind::begin_unwind::h17288900196382632715
   5:     0x7f2de1486b20 - diagnostic::SpanHandler::span_bug::hc28ba54728d5da49oZF
   6:     0x7f2de103eeb0 - middle::typeck::infer::region_inference::RegionVarBindings<'a, 'tcx>::make_subregion::h8d93dddca703b8329uc
   7:     0x7f2de104f250 - middle::typeck::infer::sub::Sub<'f, 'tcx>.Combine<'tcx>::regions::h3adc46f8245aed4eC1e
   8:     0x7f2de104eff0 - middle::typeck::infer::sub::Sub<'f, 'tcx>.Combine<'tcx>::contraregions::h20372efe4f6663fe20e
   9:     0x7f2de1051c00 - middle::typeck::infer::combine::Combine::closure_tys::h17253834835442553283
  10:     0x7f2de0ff4270 - middle::typeck::infer::sub::Sub<'f, 'tcx>.Combine<'tcx>::tys::hc0c072841551908fm9e
  11:     0x7f2de0ff4100 - middle::typeck::infer::coercion::Coerce<'f, 'tcx>::subtype::h761550d7283e2cf7y85
  12:     0x7f2de0ff3da0 - middle::typeck::infer::coercion::Coerce<'f, 'tcx>::coerce_borrowed_fn::h5519897a090d27f0uQ6
  13:     0x7f2de0ff3d40 - middle::typeck::infer::coercion::Coerce<'f, 'tcx>::tys::closure.134443
  14:     0x7f2de0ff19f0 - middle::typeck::infer::coercion::Coerce<'f, 'tcx>::unpack_actual_value::h17085816543345179750
  15:     0x7f2de0ff1150 - middle::typeck::infer::coercion::Coerce<'f, 'tcx>::tys::he0c4ea99af0e5f6fZ05
  16:     0x7f2de105a890 - middle::typeck::infer::mk_coercety::closure.136277
  17:     0x7f2de105a5f0 - middle::typeck::infer::InferCtxt<'a, 'tcx>::commit_if_ok::closure.136269
  18:     0x7f2de105a480 - middle::typeck::infer::InferCtxt<'a, 'tcx>::commit_unconditionally::h1485868009903534266
  19:     0x7f2de0d9bdc0 - middle::typeck::infer::mk_coercety::ha26368b750869d196di
  20:     0x7f2de0f31de0 - middle::typeck::check::FnCtxt<'a, 'tcx>::mk_assignty::h5bf4da584e36fc1bNkY
  21:     0x7f2de0f31a50 - middle::typeck::check::demand::coerce::h4d0a0c0e48366a432aS
  22:     0x7f2de0f9e380 - middle::typeck::check::check_expr_coercable_to_type::closure.133451
  23:     0x7f2de0f948c0 - middle::typeck::check::check_expr_with_unifier::h304cbc594fc73fa9vGZ
  24:     0x7f2de0f93000 - middle::typeck::check::check_argument_types::h86d271aa00d8ca66p7Y
  25:     0x7f2de0f948c0 - middle::typeck::check::check_expr_with_unifier::h304cbc594fc73fa9vGZ
  26:     0x7f2de0f5a4e0 - middle::typeck::check::check_block_with_expected::hfe6034b5fa76b64aBR1
  27:     0x7f2de0f55f50 - middle::typeck::check::check_fn::hd588b519b8e4dff0ViW
  28:     0x7f2de0f55c90 - middle::typeck::check::check_bare_fn::h62e026ad7d690a0da8V
  29:     0x7f2de0f51d90 - middle::typeck::check::check_item::hd44c3c50a5dfb9a2jsW
  30:     0x7f2de0f55a40 - middle::typeck::check::check_item_types::h81b3d7ebec550ce0k7V
  31:     0x7f2de0a73130 - util::common::time::h1019099971939974795
  32:     0x7f2de1272390 - middle::typeck::check_crate::h0ed70082c7a4b6f2hup
  33:     0x7f2de12d5c30 - driver::driver::phase_3_run_analysis_passes::h8e79204e3159e776IdC
  34:     0x7f2de12d0c70 - driver::driver::compile_input::hf4591f6ef7b02566tUB
  35:     0x7f2de1350e40 - driver::run_compiler::h8547738c3b140275KKF
  36:     0x7f2de1350d30 - driver::run::closure.146360
  37:     0x7f2de0a8b9e0 - task::TaskBuilder<S>::try_future::closure.104798
  38:     0x7f2de0a8b7d0 - task::TaskBuilder<S>::spawn_internal::closure.104769
  39:     0x7f2de0a543d0 - task::NativeSpawner.Spawner::spawn::closure.2582
  40:     0x7f2de2525c40 - rust_try_inner
  41:     0x7f2de2525c30 - rust_try
  42:     0x7f2de2523230 - unwind::try::h242542d3bd53ca70mYc
  43:     0x7f2de25230d0 - task::Task::run::h5e3f75748e9fc0b3u4b
  44:     0x7f2de0a54110 - task::NativeSpawner.Spawner::spawn::closure.2508
  45:     0x7f2de2524240 - thread::thread_start::heed63dda248c44e2rpc
  46:     0x7f2de02a1dc0 - start_thread
  47:                0x0 - <unknown>