ICE when building Iron

[reem]

Repo: https://github.com/iron/iron

Master at this time: iron/iron@18c0981

Backtrace:

~/h/iron git:master ❯❯❯ RUST_BACKTRACE=1 cargo build                                               
   Compiling iron v0.0.1 (file:///Users/Jonathan/rust/iron)
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. 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' failed at 'no entry found for key', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/libstd/collections/hashmap/map.rs:1093

stack backtrace:
   1:        0x104d858f9 - rt::backtrace::imp::write::h57c4b9a5e0159c2as4q
   2:        0x104d88c31 - failure::on_fail::h9597b912f48b9b706kr
   3:        0x10500eff5 - unwind::begin_unwind_inner::hc2b5226ed0282dfeVRd
   4:        0x101a1a17c - unwind::begin_unwind::h11076168068521793063
   5:        0x101c054a3 - middle::expr_use_visitor::ExprUseVisitor<'d, 't, TYPER>::walk_captures::closure.113560
   6:        0x101bec161 - middle::ty::with_freevars::h5404199086317543483
   7:        0x101c01545 - middle::expr_use_visitor::ExprUseVisitor<'d, 't, TYPER>::walk_expr::h15577293082558427187
   8:        0x101c04ebb - middle::expr_use_visitor::ExprUseVisitor<'d, 't, TYPER>::consume_expr::h4543982797502329416
   9:        0x101c0255f - middle::expr_use_visitor::ExprUseVisitor<'d, 't, TYPER>::walk_expr::h15577293082558427187
  10:        0x101c04ebb - middle::expr_use_visitor::ExprUseVisitor<'d, 't, TYPER>::consume_expr::h4543982797502329416
  11:        0x101c010c0 - middle::expr_use_visitor::ExprUseVisitor<'d, 't, TYPER>::walk_block::h7824838697509637511
  12:        0x101bfa34d - middle::borrowck::gather_loans::gather_loans_in_fn::hf96f8c6647c1d7feR3h
  13:        0x101c21d45 - middle::borrowck::build_borrowck_dataflow_data::h73b392d294a7bcf7ZQj
  14:        0x101c1f26c - middle::borrowck::borrowck_fn::h4ddc1cc1afcff2c59Nj
  15:        0x101c21493 - visit::walk_item::h4401219305633436056
  16:        0x101c2105e - visit::walk_item::h4401219305633436056
  17:        0x101c1fb4a - middle::borrowck::check_crate::h4d6d565ad7aa1decXGj
  18:        0x101a37e86 - util::common::time::h3749222828850377650
  19:        0x10225734b - driver::driver::phase_3_run_analysis_passes::he1a1b07e6ec33f9dFWw
  20:        0x1022518d8 - driver::driver::compile_input::h1037c8fe7e200b41uDw
  21:        0x1022d07d4 - driver::run_compiler::h3f1264bcc2d33c04ytA
  22:        0x1022ce976 - driver::main_args::closure.146588
  23:        0x101a5062b - task::TaskBuilder<S>::try_future::closure.101381
  24:        0x101a50523 - task::TaskBuilder<S>::spawn_internal::closure.101352
  25:        0x1019d067d - task::spawn_opts::closure.8556
  26:        0x1050721ac - rust_try_inner
  27:        0x105072196 - rust_try
  28:        0x10500bfa7 - unwind::try::h87aabef6b705df27DGd
  29:        0x10500be3c - task::Task::run::hc0753fa4c82e7ec2uWc
  30:        0x1019d04d2 - task::spawn_opts::closure.8495
  31:        0x10500df4a - thread::thread_start::h88a63edf7f210ee3Zgd
  32:     0x7fff87f71899 - _pthread_body
  33:     0x7fff87f7172a - _pthread_struct_init

Could not compile `iron`.

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

[tomjakubowski]

I got this same ICE, here's a smaller example:

#![feature(unboxed_closures)]

fn main() {
    let x = 123i;
    let _ = |&: | x;
}

Backtrace:

[tom@elbridge ~]$ rustc --version
rustc 0.12.0-dev (0c6679652 2014-09-29 21:12:16 +0000)
[tom@elbridge ~]$ RUST_BACKTRACE=1 rustc foo.rs
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. 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' failed at 'no entry found for key', /build/rust-git/src/rust/src/libstd/collections/hashmap/map.rs:1093

stack backtrace:
   1:     0x7f6eff51a720 - rt::backtrace::imp::write::ha75ba269c80f79c9UVq
   2:     0x7f6eff51d8b0 - <unknown>
   3:     0x7f6effcd2090 - unwind::begin_unwind_inner::h99aec5f720e41c37SUd
   4:     0x7f6f000a42b0 - <unknown>
   5:     0x7f6f0027f010 - <unknown>
   6:     0x7f6f0027eef0 - <unknown>
   7:     0x7f6f00293040 - <unknown>
   8:     0x7f6f00292d20 - <unknown>
   9:     0x7f6f0028cfd0 - middle::borrowck::gather_loans::gather_loans_in_fn::h7ca090ca6cfae9d2P3h
  10:     0x7f6f002b3310 - <unknown>
  11:     0x7f6f002b07c0 - <unknown>
  12:     0x7f6f002b25b0 - <unknown>
  13:     0x7f6f002b0f70 - middle::borrowck::check_crate::h676a3166f3c656faVGj
  14:     0x7f6f000c1b40 - <unknown>
  15:     0x7f6f008f9670 - driver::driver::phase_3_run_analysis_passes::h7ab4d2823326c4fcaMw
  16:     0x7f6f008f4e80 - driver::driver::compile_input::h47be44a11fe49900Zsw
  17:     0x7f6f00976e10 - <unknown>
  18:     0x7f6f00976cf0 - <unknown>
  19:     0x7f6f000daad0 - <unknown>
  20:     0x7f6f000da8c0 - <unknown>
  21:     0x7f6f01282700 - <unknown>
  22:     0x7f6effd21590 - <unknown>
  23:     0x7f6effd21580 - rust_try
  24:     0x7f6effccf220 - unwind::try::had5a0109a3678a47AJd
  25:     0x7f6effccf0b0 - task::Task::run::h1ae56ff3a9ffb576UYc
  26:     0x7f6f01282470 - <unknown>
  27:     0x7f6effcd1130 - <unknown>
  28:     0x7f6efefe4250 - start_thread
  29:     0x7f6eff9a83b9 - clone
  30:                0x0 - <unknown>

[brson]

This is unfortunate. I wonder if somebody can bisect and revert. Any changes to closure type checking recently that may have triggered this?

cc @pcwalton @nick29581 @eddyb

[jgallagher]

I'm super new to rust, so I'll leave the reverting to you guys. I did do the bisect - the commit that introduced this is 2257e23

[huonw]

A work around (for @tomjakubowski's example at least) is using capture-by-move, e.g.

#![feature(unboxed_closures)]

fn main() {
    let x = 123i;
    let _ = move |&: | x;
}

[reem]

That's what I tried in iron too, looks like it's working.

[huonw]

Closing as a dupe of #17655. (Thanks for bisecting @jgallagher!)