ICE Cannot relate bound region

[Kintaro]

I hit an internal compiler error with this weeks build. It occurs when I try to build https://github.com/Kintaro/wtftw/tree/1d8040fddfedfd3b111bb4d5a8466fcb8120e339

Error output and rustc version are below.

rustc 1.2.0-dev (0fc0476 2015-05-24) (built 2015-05-24)

Unfortunately, #25652 did not fix the issue. It's caused by this part here https://github.com/Kintaro/wtftw/blob/1d8040fddfedfd3b111bb4d5a8466fcb8120e339/core/src/config.rs#L110

core/src/config.rs:116:13: 116:28 error: internal compiler error: cannot relate bound region: ReScope(Remainder(BlockRemainder { block: 150, first_statement_index: 3 })) <= ReLateBound(DebruijnIndex { depth: 1 }, BrAnon(0))
core/src/config.rs:116         let internal_config = 
                                   ^~~~~~~~~~~~~~~
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: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', /home/rootnode/programs/src/rust/src/libsyntax/diagnostic.rs:176

[Kintaro]

Forgot to add the backtrace:

stack backtrace:
   1:     0x7f947750c183 - sys::backtrace::write::h615fdb4d732e4a93r6r
   2:     0x7f9477514049 - panicking::on_panic::h9a7e45e333684aa03Lw
   3:     0x7f94774d4e3a - rt::unwind::begin_unwind_inner::h995a60547c3f562eNrw
   4:     0x7f947482cbbd - rt::unwind::begin_unwind::h17375738179658217201
   5:     0x7f947482cb52 - diagnostic::SpanHandler::span_bug::h8482da51d213c57buqC
   6:     0x7f9475553cda - middle::infer::region_inference::RegionVarBindings<'a, 'tcx>::make_subregion::hb699f35a3cfa39c6UPv
   7:     0x7f947556cd1f - middle::infer::mk_subr::h93c112efb784e579G5y
   8:     0x7f9476c3ba0f - check::regionck::type_must_outlive::h68e52339b49b7368Tte
   9:     0x7f9476c39baa - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h80326f55a8cc05afZDa
  10:     0x7f9476c39d5c - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h80326f55a8cc05afZDa
  11:     0x7f9476c39d5c - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h80326f55a8cc05afZDa
  12:     0x7f9476c39f13 - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h80326f55a8cc05afZDa
  13:     0x7f9476c39d5c - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h80326f55a8cc05afZDa
  14:     0x7f9476c39d5c - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h80326f55a8cc05afZDa
  15:     0x7f9476c39d5c - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h80326f55a8cc05afZDa
  16:     0x7f9476c38738 - check::dropck::check_safety_of_destructor_if_necessary::h6d78b805219652e19xa
  17:     0x7f9476c7033d - check::regionck::check_safety_of_rvalue_destructor_if_necessary::ha65a719fd22d79bdjPd
  18:     0x7f9476c69b81 - check::regionck::visit_expr::h15cc0f7c6e849ab0fad
  19:     0x7f9476c67bb1 - check::regionck::Rcx<'a, 'tcx>::visit_fn_body::h461f8d4e496574beHMc
  20:     0x7f9476c67090 - check::regionck::regionck_fn::hf51a587df53131353Ec
  21:     0x7f9476ce2dc8 - check::check_bare_fn::h56477091183bbe08gOn
  22:     0x7f9476ceed5c - check::check_method_body::h11b8e4f5d8c75e9crro
  23:     0x7f9476ce0913 - check::check_item_body::hc9468be7e10fb9049eo
  24:     0x7f9476ce0f02 - visit::walk_item::h10209465936042145449
  25:     0x7f9476ce278f - check::check_item_types::h22d39728d2ed74ffNLn
  26:     0x7f9476d9f026 - check_crate::h0c48e68f075d51d7g7C
  27:     0x7f9477a68d9f - driver::phase_3_run_analysis_passes::h34501209e3394a5cGGa
  28:     0x7f9477a4bf3c - driver::compile_input::h69c18a97a3bef03fQba
  29:     0x7f9477b01b31 - run_compiler::h737927eeae91ebd5n6b
  30:     0x7f9477aff382 - boxed::F.FnBox<A>::call_box::h1962494538046773488
  31:     0x7f9477afeb89 - rt::unwind::try::try_fn::h2931293082837064848
  32:     0x7f9477597138 - rust_try_inner
  33:     0x7f9477597125 - rust_try
  34:     0x7f94774ffc37 - rt::unwind::try::inner_try::h80226bb4deb2a8ebGnw
  35:     0x7f9477afeda9 - boxed::F.FnBox<A>::call_box::h2098047553192396313
  36:     0x7f9477512d01 - sys::thread::Thread::new::thread_start::h97730f674d383241Sxv
  37:     0x7f9471f720a3 - start_thread
  38:     0x7f947715c04c - clone
  39:                0x0 - <unknown>

[Kintaro]

Ok, I was able to produce a small example that causes it:

use std::collections::BTreeMap;

pub type ManageHook = Box<Fn(Workspaces, &WindowSystem, Window) -> Workspaces>;
pub type LogHook = Box<FnMut(WindowManager, &WindowSystem)>;

pub trait WindowSystem {}
pub struct WindowManager;
pub struct Workspaces;
pub type Window = u64;

pub struct GeneralConfig;

pub struct InternalConfig {
    pub manage_hook: ManageHook,
    pub loghook: Option<LogHook>,
}

impl InternalConfig {
    pub fn new(manage_hook: ManageHook) -> InternalConfig {
        InternalConfig {
            manage_hook: manage_hook,
            loghook: None,
        }
    }
}

fn main() {
}

http://is.gd/UnSdRQ

[betawaffle]

Reduced even further:

pub type BoxedFn = Box<Fn(&Trait)>;

pub trait Trait {}

pub fn new() -> Option<(BoxedFn, BoxedFn)> {
    None
}

src/lib.rs:6:5: 6:9 error: internal compiler error: cannot relate bound region: ReScope(DestructionScope(18)) <= ReLateBound(DebruijnIndex { depth: 1 }, BrAnon(0))
src/lib.rs:6     None
                 ^~~~
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
thread 'rustc' panicked at 'Box<Any>', /Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/src/libsyntax/diagnostic.rs:176

stack backtrace:
   1:        0x1089077b5 - sys::backtrace::write::h1561c90743d5c179M9r
   2:        0x1089103f0 - panicking::on_panic::h8a5d860d5a124e0a2uw
   3:        0x1088ca948 - rt::unwind::begin_unwind_inner::hb33d13fc310a98afkdw
   4:        0x10807987e - rt::unwind::begin_unwind::h9699143272701214950
   5:        0x10807980a - diagnostic::SpanHandler::span_bug::h4a339f86ecbb72a1uqC
   6:        0x105ae38b4 - middle::infer::region_inference::RegionVarBindings<'a, 'tcx>::make_subregion::h30bc770a31311672yRv
   7:        0x105afdf1b - middle::infer::mk_subr::h9a5b48e4c252ec91k7y
   8:        0x105606b2a - check::regionck::type_must_outlive::h8d529e58bca1ccb0Tte
   9:        0x105604ac5 - check::dropck::iterate_over_potentially_unsafe_regions_in_type::ha9d169bb6b0bbca3ZDa
  10:        0x105604e1e - check::dropck::iterate_over_potentially_unsafe_regions_in_type::ha9d169bb6b0bbca3ZDa
  11:        0x105603701 - check::dropck::check_safety_of_destructor_if_necessary::h3060ac778c5992289xa
  12:        0x10563d93e - check::regionck::check_safety_of_rvalue_destructor_if_necessary::hcf8a4293ce5c60bfjPd
  13:        0x105636eb3 - check::regionck::visit_expr::h79aea6e9fda81e97fad
  14:        0x105634cde - check::regionck::Rcx<'a, 'tcx>::visit_fn_body::h09869d1c412f3624HMc
  15:        0x1056340a3 - check::regionck::regionck_fn::hfdd6d8acf07f17563Ec
  16:        0x1056b133d - check::check_bare_fn::hc9c7a17ca1e4729egOn
  17:        0x1056aef37 - check::check_item_body::h103df4808fcb6e559eo
  18:        0x1056b0c73 - check::check_item_types::h7c6eaf781d12ace8NLn
  19:        0x105770f10 - check_crate::h8fe4e687b73e5015g7C
  20:        0x104f9b68f - driver::phase_3_run_analysis_passes::hef736cb124de6565GGa
  21:        0x104f7f403 - driver::compile_input::h7a3800e0d9c4bbe3Qba
  22:        0x105039e04 - run_compiler::h3864143d185b8964n6b
  23:        0x10503756a - boxed::F.FnBox<A>::call_box::h4644100161726726905
  24:        0x105036c87 - rt::unwind::try::try_fn::h5144344175023612934
  25:        0x108998bf8 - rust_try_inner
  26:        0x108998be5 - rust_try
  27:        0x1088fa315 - rt::unwind::try::inner_try::hbe91c83f4d153e36d9v
  28:        0x105036ee2 - boxed::F.FnBox<A>::call_box::h10871128639736673174
  29:        0x10890eeed - sys::thread::Thread::new::thread_start::h89e4611b0ac51fcbMxv
  30:     0x7fff8852a267 - _pthread_body
  31:     0x7fff8852a1e4 - _pthread_start

[betawaffle]

And, once again:

# Fails
fn fail() -> Option<(Box<Fn(&Sized)>, Box<Fn(&Sized)>)> {
    None
}

# Works
fn work<'a>() -> Option<(Box<Fn(&'a Sized)>, Box<Fn(&'a Sized)>)> {
    None
}

[marcmmiller]

FWIW, I ran into this also, but don't have time to whittle this down to a small repro.

$ rustc --version
rustc 1.0.0 (a59de37 2015-05-13) (built 2015-05-14)

main.rs:532:37: 532:41 error: internal compiler error: cannot relate bound region: ReScope(DestructionScope(3503)) <= ReLateBound(DebruijnIndex { depth: 1 }, BrAnon(0))
main.rs:532 Builtin { name: name, func: func }
^~~~
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: run with RUST_BACKTRACE=1 for a backtrace
thread 'rustc' panicked at 'Box', /Users/rustbuild/src/rust-buildbot/slave/stable-dist-rustc-mac/build/src/libsyntax/diagnostic.rs:149

stack backtrace:
1: 0x10eb59e7f - sys::backtrace::write::h7807ec07859fb503t1r
2: 0x10eb624b2 - panicking::on_panic::ha0ed2b9b562a7f9ctZv
3: 0x10eb1ee35 - rt::unwind::begin_unwind_inner::hbfb8d99cb52be7a1cHv
4: 0x10e30743e - rt::unwind::begin_unwind::h14482673826369992638
5: 0x10e3073ca - diagnostic::SpanHandler::span_bug::ha80d5103c6dc346fEqB
6: 0x10c1ccc2b - middle::infer::region_inference::RegionVarBindings<'a, 'tcx>::make_subregion::h424c309cfde0bc8dtiv
7: 0x10c1e8a90 - middle::infer::mk_subr::h4f040a8108e68139XWy
8: 0x10b7c14ed - check::regionck::type_must_outlive::hb12e90041719991fQBe
9: 0x10b7bf0bd - check::dropck::iterate_over_potentially_unsafe_regions_in_type::h5b033045bf4886b5CDa
10: 0x10b7bde51 - check::dropck::check_safety_of_destructor_if_necessary::h7327a46d7b6457bcMxa
11: 0x10b7f26de - check::regionck::check_safety_of_rvalue_destructor_if_necessary::hdb7e84c483faff56gXd
12: 0x10b7ebd04 - check::regionck::visit_expr::hcfb3f0e73f4f1ee5Yhd
13: 0x10b7f310e - visit::walk_expr::h8074881990300037598
14: 0x10b7ec8e9 - check::regionck::visit_expr::hcfb3f0e73f4f1ee5Yhd
15: 0x10b7e9d8e - check::regionck::Rcx<'a, 'tcx>::visit_fn_body::h6ad291664793346cpUc
16: 0x10b866cc7 - check::check_bare_fn::h87d6505bed3e4c61twn
17: 0x10b86f887 - check::check_method_body::h1802c6d6e15675a6Y7n
18: 0x10b8648cb - check::CheckItemBodiesVisitor<'a, 'tcx>.Visitor<'tcx>::visit_item::h97ae569543a98538wtn
19: 0x10b92ef4a - check_crate::closure.38028
20: 0x10b92a357 - check_crate::h722813c75c795e06XcC
21: 0x10b6945f4 - driver::phase_3_run_analysis_passes::h3394cefeecbff846nGa
22: 0x10b675ffc - driver::compile_input::hf0607b3d1fd498bcQba
23: 0x10b73e5a3 - run_compiler::he7a5311c755081d7z4b
24: 0x10b73c0ca - boxed::F.FnBox::call_box::h5234503372052129763
25: 0x10b73b567 - rt::unwind::try::try_fn::h4031265711883657142
26: 0x10ebe3508 - rust_try_inner
27: 0x10ebe34f5 - rust_try
28: 0x10b73b840 - boxed::F.FnBox::call_box::h1044299548107784679
29: 0x10eb60ffd - sys::thread::create::thread_start::ha3be9b31a8775143L4u
30: 0x7fff99511898 - _pthread_body
31: 0x7fff99511729 - _pthread_start