Crash on opening an empty rust file

[luctius]

Reproduction steps

touch test.rs
hx test.rs

Environment

• Platform: Linux
• Helix version: v0.4.1-3-g7892349

please provide a copy of `~/.cache/helix/helix.log`: <empty>

RUST_BACKTRACE=full test.rs
thread 'main' panicked at 'attempt to subtract with overflow', helix-core/src/match_brackets.rs:29:20
stack backtrace:
0: 0x55a1ec74ecd0 - std::backtrace_rs::backtrace::libunwind::trace::h34055254b57d8e79
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
1: 0x55a1ec74ecd0 - std::backtrace_rs::backtrace::trace_unsynchronized::h8f1e3fbd9afff6ec
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
2: 0x55a1ec74ecd0 - std::sys_common::backtrace::_print_fmt::h3a99a796b770c360
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:67:5
3: 0x55a1ec74ecd0 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h32d1f94a80615d18
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:46:22
4: 0x55a1ec774b8c - core::fmt::write::h306731c068f7162c
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/fmt/mod.rs:1110:17
5: 0x55a1ec749775 - std::io::Write::write_fmt::hd2fa90334eee2a21
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/io/mod.rs:1588:15
6: 0x55a1ec750feb - std::sys_common::backtrace::_print::h5abaa2601a852287
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:49:5
7: 0x55a1ec750feb - std::sys_common::backtrace::print::h8d81445442bb638f
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:36:9
8: 0x55a1ec750feb - std::panicking::default_hook::{{closure}}::hcfe804496a9fa747
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:208:50
9: 0x55a1ec750ac1 - std::panicking::default_hook::hbea8e3ccf2ba8901
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:225:9
10: 0x55a1eb8728f3 - <alloc::boxed::Box<F,A> as core::ops::function::Fn>::call::h804bfd6e32dccdae
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/alloc/src/boxed.rs:1589:9
11: 0x55a1eb8d8143 - helix_term::application::Application::run::{{closure}}::{{closure}}::hd6a5c1f7eb07743d
at /home/cor/workspace/helix/helix-term/src/application.rs:525:13
12: 0x55a1ec7516d9 - std::panicking::rust_panic_with_hook::h7ee9e1a2d0f8975a
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:626:17
13: 0x55a1ec751167 - std::panicking::begin_panic_handler::{{closure}}::h8ab3b4491718b2c7
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:517:13
14: 0x55a1ec74f1cc - std::sys_common::backtrace::__rust_end_short_backtrace::hd489062ffa586a9f
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:141:18
15: 0x55a1ec7510f9 - rust_begin_unwind
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:515:5
16: 0x55a1eb86f9c1 - core::panicking::panic_fmt::hca6330e3e14086b4
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/panicking.rs:92:14
17: 0x55a1eb86f90d - core::panicking::panic::h1a48d878ff3dcd40
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/panicking.rs:50:5
18: 0x55a1ec37d8a3 - helix_core::match_brackets::find::hca825031d79f9972
at /home/cor/workspace/helix/helix-core/src/match_brackets.rs:29:20
19: 0x55a1eb9d806e - helix_term::ui::editor::EditorView::render_focused_view_elements::he00c47c2c26dc733
at /home/cor/workspace/helix/helix-term/src/ui/editor.rs:433:31
20: 0x55a1eb9d63a4 - helix_term::ui::editor::EditorView::render_view::h34f706b370c28787
at /home/cor/workspace/helix/helix-term/src/ui/editor.rs:101:13
21: 0x55a1eb9dd8ef - <helix_term::ui::editor::EditorView as helix_term::compositor::Component>::render::h78c955832947fb24
at /home/cor/workspace/helix/helix-term/src/ui/editor.rs:1049:13
22: 0x55a1ebafc116 - helix_term::compositor::Compositor::render::h3ebcc89db186be85
at /home/cor/workspace/helix/helix-term/src/compositor.rs:156:13
23: 0x55a1ebbc85a0 - helix_term::application::Application::render::h9975e15aa54f268f
at /home/cor/workspace/helix/helix-term/src/application.rs:151:9
24: 0x55a1eb8d15b1 - helix_term::application::Application::event_loop::{{closure}}::hc17a2ea0183b09f2
at /home/cor/workspace/helix/helix-term/src/application.rs:159:9
25: 0x55a1eb88db0b - <core::future::from_generator::GenFuture as core::future::future::Future>::poll::h3c7fa6e2cee7e5d9
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/future/mod.rs:80:19
26: 0x55a1eb8d7b57 - helix_term::application::Application::run::{{closure}}::h8c8d5631784629b0
at /home/cor/workspace/helix/helix-term/src/application.rs:528:9
27: 0x55a1eb88d789 - <core::future::from_generator::GenFuture as core::future::future::Future>::poll::h2275225d59b3386b
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/future/mod.rs:80:19
28: 0x55a1eb87b266 - hx::main::{{closure}}::h73ee7ead5049093c
at /home/cor/workspace/helix/helix-term/src/main.rs:97:5
29: 0x55a1eb88e199 - <core::future::from_generator::GenFuture as core::future::future::Future>::poll::he7974cbdf8f5830b
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/future/mod.rs:80:19
30: 0x55a1eb88aef0 - tokio::park::thread::CachedParkThread::block_on::{{closure}}::hd95c0b3130521685
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/park/thread.rs:263:54
31: 0x55a1eb8f2982 - tokio::coop::with_budget::{{closure}}::hc1b712d11919770a
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/coop.rs:106:9
32: 0x55a1eb88c5e3 - std::thread::local::LocalKey::try_with::h6ea8dfae055eb6b2
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/thread/local.rs:400:16
33: 0x55a1eb88c00d - std::thread::local::LocalKey::with::h2987a295d1e1bcd0
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/thread/local.rs:376:9
34: 0x55a1eb88a7c1 - tokio::coop::with_budget::h9bb45885fe5887cb
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/coop.rs:99:5
35: 0x55a1eb88a7c1 - tokio::coop::budget::hee919c8f5bac2064
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/coop.rs:76:5
36: 0x55a1eb88a7c1 - tokio::park::thread::CachedParkThread::block_on::h1b44a71178dd5efd
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/park/thread.rs:263:31
37: 0x55a1eb8a3cbe - tokio::runtime::enter::Enter::block_on::h5d9b22ce457dc892
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/runtime/enter.rs:151:13
38: 0x55a1eb8aa073 - tokio::runtime::thread_pool::ThreadPool::block_on::h97b86c2d89c38828
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/runtime/thread_pool/mod.rs:71:9
39: 0x55a1eb876125 - tokio::runtime::Runtime::block_on::hee92157c97ebddc7
at /home/cor/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tokio-1.10.0/src/runtime/mod.rs:452:43
40: 0x55a1eb8dadd7 - hx::main::h20f0f8a2189186fa
at /home/cor/workspace/helix/helix-term/src/main.rs:99:5
41: 0x55a1eb8dd8ab - core::ops::function::FnOnce::call_once::hf6bba9bb11a21409
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/ops/function.rs:227:5
42: 0x55a1eb884ade - std::sys_common::backtrace::__rust_begin_short_backtrace::h32804997305a0dfa
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:125:18
43: 0x55a1eb870991 - std::rt::lang_start::{{closure}}::he4a615ec4820b768
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/rt.rs:49:18
44: 0x55a1ec751cb9 - core::ops::function::impls::<impl core::ops::function::FnOnce for &F>::call_once::h2aabc384aab89b7b
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/ops/function.rs:259:13
45: 0x55a1ec751cb9 - std::panicking::try::do_call::hc5fcacb7a85fc7b1
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:401:40
46: 0x55a1ec751cb9 - std::panicking::try::hb5d9603af3abbe3a
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:365:19
47: 0x55a1ec751cb9 - std::panic::catch_unwind::h98fe6ac3925e64b4
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panic.rs:434:14
48: 0x55a1ec751cb9 - std::rt::lang_start_internal::h22ac7383c516f93e
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/rt.rs:34:21
49: 0x55a1eb870970 - std::rt::lang_start::h0978ff56c1a2b646
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/rt.rs:48:5
50: 0x55a1eb8dae5c - main
51: 0x7f96bcc5e565 - __libc_start_main
52: 0x55a1eb8701be - _start
53: 0x0 -