ICE: /checkout/src/librustc/infer/mod.rs:573

[nrxus]

I updated my nightly toolchain tonight and got this error when attempting to compile:

Compiling sdl2 v0.30.0
error: internal compiler error: /checkout/src/librustc/infer/mod.rs:573: Encountered errors `[FulfillmentError(Obligation(predicate=Binder(TraitPredicate(<CB as audio::AudioCallback>)),depth=0),Unimplemented)]` resolving bounds after type-checking

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 1.20.0-nightly (582af6e1a 2017-07-19) running on x86_64-unknown-linux-gnu

thread 'rustc' panicked at 'Box<Any>', /checkout/src/librustc_errors/lib.rs:437:8
note: Run with `RUST_BACKTRACE=1` for a backtrace.

error: Could not compile `sdl2`.

I did a bit of digging by overriding my toolchain manually, and found that as of yesterday's nightly (83c659e 2017-07-18) my code compiles fine:

$ rustup override set nightly-2017-07-19
info: using existing install for 'nightly-2017-07-19-x86_64-unknown-linux-gnu'
info: override toolchain for '<redacted>' set to 'nightly-2017-07-19-x86_64-unknown-linux-gnu'

  nightly-2017-07-19-x86_64-unknown-linux-gnu unchanged - rustc 1.20.0-nightly (83c659ef6 2017-07-18)

$ cargo check
   Compiling duck_husky_wedding v0.1.0 (<redacted>)
warning: unused variable: `flip`
  --> src/duck_husky_wedding/body.rs:16:57
   |
16 |     pub fn new(rect: &glm::DVec4, body: &[data::Shape], flip: bool) -> Self {
   |                                                         ^^^^
   |
   = note: #[warn(unused_variables)] on by default

warning: unused variable: `interpolation`
   --> src/duck_husky_wedding/mod.rs:107:17
    |
107 |             let interpolation = delta.subsec_nanos() as f64 / update_duration.subsec_nanos() as f64;
    |                 ^^^^^^^^^^^^^

    Finished dev [unoptimized + debuginfo] target(s) in 1.13 secs

Switching the toolchain to the day after though, produces the ICE:

$ rustup override set nightly-2017-07-20
info: using existing install for 'nightly-2017-07-20-x86_64-unknown-linux-gnu'
info: override toolchain for '<redacted>' set to 'nightly-2017-07-20-x86_64-unknown-linux-gnu'

  nightly-2017-07-20-x86_64-unknown-linux-gnu unchanged - rustc 1.20.0-nightly (582af6e1a 2017-07-19)

$ cargo check
   Compiling sdl2 v0.30.0
error: internal compiler error: /checkout/src/librustc/infer/mod.rs:573: Encountered errors `[FulfillmentError(Obligation(predicate=Binder(TraitPredicate(<CB as audio::AudioCallback>)),depth=0),Unimplemented)]` resolving bounds after type-checking

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 1.20.0-nightly (582af6e1a 2017-07-19) running on x86_64-unknown-linux-gnu

thread 'rustc' panicked at 'Box<Any>', /checkout/src/librustc_errors/lib.rs:437:8
note: Run with `RUST_BACKTRACE=1` for a backtrace.

error: Could not compile `sdl2`.

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

For reference, here is a full stack trace:

$ RUST_BACKTRACE=full cargo check
   Compiling sdl2 v0.30.0
error: internal compiler error: /checkout/src/librustc/infer/mod.rs:573: Encountered errors `[FulfillmentError(Obligation(predicate=Binder(TraitPredicate(<CB as audio::AudioCallback>)),depth=0),Unimplemented)]` resolving bounds after type-checking

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 1.20.0-nightly (582af6e1a 2017-07-19) running on x86_64-unknown-linux-gnu

note: run with `RUST_BACKTRACE=1` for a backtrace

thread 'rustc' panicked at 'Box<Any>', /checkout/src/librustc_errors/lib.rs:437:8
stack backtrace:
   0:     0x7f0ac943da03 - std::sys::imp::backtrace::tracing::imp::unwind_backtrace::h0155dbb6ca59ce6e
                               at /checkout/src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1:     0x7f0ac94380e4 - std::sys_common::backtrace::_print::h5f4f2ec19ff00311
                               at /checkout/src/libstd/sys_common/backtrace.rs:71
   2:     0x7f0ac944b883 - std::panicking::default_hook::{{closure}}::hafc0eefa360df4ab
                               at /checkout/src/libstd/sys_common/backtrace.rs:60
                               at /checkout/src/libstd/panicking.rs:380
   3:     0x7f0ac944b578 - std::panicking::default_hook::h83538a8b6a433831
                               at /checkout/src/libstd/panicking.rs:390
   4:     0x7f0ac944bd87 - std::panicking::rust_panic_with_hook::hae3224b5f6b814fd
                               at /checkout/src/libstd/panicking.rs:611
   5:     0x7f0ac60fceb8 - std::panicking::begin_panic_new::h6672f948a100c2a1
   6:     0x7f0ac60e72a1 - rustc_errors::Handler::span_bug::hc43628812f7bb545
   7:     0x7f0ac63254e3 - rustc::session::opt_span_bug_fmt::{{closure}}::h36f1c23dee0ab88c
   8:     0x7f0ac6325202 - rustc::session::opt_span_bug_fmt::hb3234649816b9313
   9:     0x7f0ac63250d3 - rustc::session::span_bug_fmt::h7088a0e5e41c572a
  10:     0x7f0ac63dd45f - <&'gcx rustc::ty::TyS<'gcx> as rustc::infer::TransNormalize<'gcx>>::trans_normalize::hf754271ad7f5ecb6
  11:     0x7f0ac629f07d - rustc::infer::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'tcx>>::normalize_associated_type_in_env::h302f650510c2da58
  12:     0x7f0ac637f5e1 - rustc::ty::layout::Layout::compute_uncached::h7f115120b7e746d8
  13:     0x7f0ac63a35ca - rustc::ty::util::layout_raw::h8e132d2c99ca2da6
  14:     0x7f0ac644a819 - rustc::ty::maps::<impl rustc::ty::maps::queries::layout_raw<'tcx>>::try_get::h00900307c9b08a50
  15:     0x7f0ac64575ff - rustc::ty::maps::TyCtxtAt::layout_raw::hc104cf8d0b71516c
  16:     0x7f0ac645270d - rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::layout_raw::had53de086a1553d2
  17:     0x7f0ac6cc0784 - rustc_const_eval::eval::eval_const_expr_partial::{{closure}}::hdf1b1c1933b44d19
  18:     0x7f0ac6cba933 - rustc_const_eval::eval::eval_const_expr_partial::h5a0fa592a92b3a61
  19:     0x7f0ac6cba5fb - rustc_const_eval::eval::eval_const_expr_partial::h5a0fa592a92b3a61
  20:     0x7f0ac6cba5fb - rustc_const_eval::eval::eval_const_expr_partial::h5a0fa592a92b3a61
  21:     0x7f0ac6cbdf72 - rustc_const_eval::eval::eval_const_expr_partial::h5a0fa592a92b3a61
  22:     0x7f0ac6cb9ca0 - rustc_const_eval::eval::ConstContext::eval::h383a143d122477ef
  23:     0x7f0ac8b8b740 - <rustc_passes::consts::CheckCrateVisitor<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hf35ee466267e49b2
  24:     0x7f0ac8b8b5d5 - <rustc_passes::consts::CheckCrateVisitor<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hf35ee466267e49b2
  25:     0x7f0ac8b8b1ce - <rustc_passes::consts::CheckCrateVisitor<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hf35ee466267e49b2
  26:     0x7f0ac8b8b3c7 - <rustc_passes::consts::CheckCrateVisitor<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hf35ee466267e49b2
  27:     0x7f0ac8b8b5d5 - <rustc_passes::consts::CheckCrateVisitor<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hf35ee466267e49b2
  28:     0x7f0ac8b8a0b9 - <rustc_passes::consts::CheckCrateVisitor<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_nested_body::hefec5d46b6b699fa
  29:     0x7f0ac8b8bddc - rustc_passes::consts::check_crate::h923f5bb61e5540fc
  30:     0x7f0ac97ed4a5 - rustc_driver::driver::phase_3_run_analysis_passes::{{closure}}::h60b971f27694dab9
  31:     0x7f0ac97e5bc3 - rustc_driver::driver::phase_3_run_analysis_passes::hd1ef7181394c7568
  32:     0x7f0ac97c6ecd - rustc_driver::driver::compile_input::h0c538d591196658d
  33:     0x7f0ac980c195 - rustc_driver::run_compiler::h00b9147f2ffd288b
  34:     0x7f0ac9725247 - std::sys_common::backtrace::__rust_begin_short_backtrace::hefa140dc360bd2e2
  35:     0x7f0ac947b2cc - __rust_maybe_catch_panic
                               at /checkout/src/libpanic_unwind/lib.rs:98
  36:     0x7f0ac975c9b0 - <F as alloc::boxed::FnBox<A>>::call_box::haaadeb4d67112a83
  37:     0x7f0ac944a77b - std::sys::imp::thread::Thread::new::thread_start::heb3ab1fa2e79a8b9
                               at /checkout/src/liballoc/boxed.rs:661
                               at /checkout/src/libstd/sys_common/thread.rs:21
                               at /checkout/src/libstd/sys/unix/thread.rs:84
  38:     0x7f0ac45cf6b9 - start_thread
  39:     0x7f0ac90f13dc - clone
  40:                0x0 - <unknown>

error: Could not compile `sdl2`.

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

I saw this other bug (#42950) that might be related but it seems to be much older, while this one just appeared on the latest nightly.

Hope I provided enough info!

[SpaceManiac]

Same as #43394

[nrxus]

Looks like it was fixed in #43505.