crash: goblin crate

[matthiaskrgr]

clippy @ 78860a7

git clone https://github.com/m4b/goblin
cd goblin
RUST_BACKTRACE=full ~/vcs/github/rust-clippy/target/debug/cargo-clippy  --all-targets --all-features -vvvv -- --cap-lints warn

warning: the loop variable `i` is only used to index `__tmp`.
  --> src/mach/load_command.rs:33:45
   |
33 | #[derive(Debug, Clone, Copy, Pread, Pwrite, IOread, IOwrite, SizeWith)]
   |                                             ^^^^^^
   |
   = note: #[warn(clippy::needless_range_loop)] on by default
   = help: for further information visit https://rust-lang-nursery.github.io/rust-clippy/v0.0.212/index.html#needless_range_loop
thread 'main' panicked at 'begin <= end (50 <= 44) when slicing `#[derive(Debug, Clone, Copy, Pread, Pwrite, IOread, IOwrite, SizeWith)]`', libcore/str/mod.rs:2098:5
stack backtrace:
   0:     0x7ff53ef3081f - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::h6a694a6fa8ba17f1
                               at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1:     0x7ff53ef15af7 - std::sys_common::backtrace::print::h6098d2174773bf24
                               at libstd/sys_common/backtrace.rs:71
                               at libstd/sys_common/backtrace.rs:59
   2:     0x7ff53ef3bd8f - std::panicking::default_hook::{{closure}}::h6a369d41f0b59dc6
                               at libstd/panicking.rs:211
   3:     0x7ff53ef3baf4 - std::panicking::default_hook::h69e096c824399f0d
                               at libstd/panicking.rs:227
   4:     0x7ff540f56ba1 - rustc::util::common::panic_hook::h954559df59c3b99d
   5:     0x7ff53ef3c586 - std::panicking::rust_panic_with_hook::h6a769c870f26d7a5
                               at libstd/panicking.rs:480
   6:     0x7ff53ef3c0d1 - std::panicking::continue_panic_fmt::h1e76a7a6894fe14c
                               at libstd/panicking.rs:390
   7:     0x7ff53ef3bfb5 - rust_begin_unwind
                               at libstd/panicking.rs:325
   8:     0x7ff53ef9de6c - core::panicking::panic_fmt::he6745b6f5d7fdc6a
                               at libcore/panicking.rs:77
   9:     0x7ff53ef88cd1 - core::str::slice_error_fail::hf18e3c072f612c55
                               at libcore/str/mod.rs:0
  10:     0x7ff53fd799b1 - core::str::traits::<impl core::slice::SliceIndex<str> for core::ops::range::Range<usize>>::index::{{closure}}::hcb4e89d58babca7a
  11:     0x7ff53fd7a0c9 - rustc_errors::CodeSuggestion::splice_lines::push_trailing::h7312af60c8a7b34e
  12:     0x7ff53fd5f3f5 - <core::iter::Map<I, F> as core::iter::iterator::Iterator>::fold::h47ef6bbda2fd3c8c
  13:     0x7ff53fd6d325 - <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T, I>>::from_iter::h012ff544f8cecff6
  14:     0x7ff53fd53094 - <rustc_errors::emitter::EmitterWriter as rustc_errors::emitter::Emitter>::emit::h3c7dd4e007e42687
  15:     0x7ff53fd7cb43 - rustc_errors::Handler::emit_db::h115eb14c816948d7
  16:     0x7ff53fd68987 - rustc_errors::diagnostic_builder::DiagnosticBuilder::emit::ha4a7047a8b407aa9
  17:     0x56455233435e - <clippy_lints::utils::DiagnosticWrapper<'a> as core::ops::drop::Drop>::drop::h73d2572bd2cb53ae
                               at clippy_lints/src/utils/mod.rs:502
  18:     0x56455230d7e4 - core::ptr::drop_in_place::h14e2a7817529e69e
                               at libcore/ptr.rs:194
  19:     0x56455225b38c - clippy_lints::utils::span_lint_and_then::h42a7d6d7c4372d8f
                               at clippy_lints/src/utils/mod.rs:563
  20:     0x56455224ba71 - clippy_lints::loops::check_for_loop_range::h53307629e1b4ea43
                               at clippy_lints/src/loops.rs:1131
  21:     0x564552248d48 - clippy_lints::loops::check_for_loop::h56e8de59b5e25744
                               at clippy_lints/src/loops.rs:744
  22:     0x5645522465ff - <clippy_lints::loops::Pass as rustc::lint::LateLintPass<'a, 'tcx>>::check_expr::h9dd7ad343f9ed9ea
                               at clippy_lints/src/loops.rs:452
  23:     0x7ff540f2bf70 - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hacce8715a21088ed
  24:     0x7ff540f2de61 - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_local::h7a9f56233283d971
  25:     0x7ff540f2e0ec - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_block::h009b0eec069ac065
  26:     0x7ff540f2c03a - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hacce8715a21088ed
  27:     0x7ff540f2e0ec - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_block::h009b0eec069ac065
  28:     0x7ff540f2c03a - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hacce8715a21088ed
  29:     0x7ff540ebff8f - rustc::hir::intravisit::walk_expr::hc63fdf174e426d73
  30:     0x7ff540f2c03a - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hacce8715a21088ed
  31:     0x7ff540f2de61 - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_local::h7a9f56233283d971
  32:     0x7ff540f2e0ec - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_block::h009b0eec069ac065
  33:     0x7ff540f2c03a - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_expr::hacce8715a21088ed
  34:     0x7ff540f2b09f - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_body::h32fe4c60a6ab41f7
  35:     0x7ff540f2aeda - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_nested_body::hdd5a93d01d7ac742
  36:     0x7ff540f2c7c4 - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_fn::h22917daef4a8b501
  37:     0x7ff540eac86f - rustc::hir::intravisit::walk_impl_item::h1f6950020260656a
  38:     0x7ff540f2f7ab - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_impl_item::hea6c1838b7c2ed20
  39:     0x7ff540eafdab - rustc::hir::intravisit::walk_impl_item_ref::ha1602df357497b7f
  40:     0x7ff540e8508e - rustc::hir::intravisit::walk_item::he9d61edd2c8d86e4
  41:     0x7ff540f2b59b - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item::h913aa09c54c17ff3
  42:     0x7ff540f2daa0 - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_mod::h02594b4f3e3330ae
  43:     0x7ff540e84ed5 - rustc::hir::intravisit::walk_item::he9d61edd2c8d86e4
  44:     0x7ff540f2b59b - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item::h913aa09c54c17ff3
  45:     0x7ff540f2daa0 - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_mod::h02594b4f3e3330ae
  46:     0x7ff540e84ed5 - rustc::hir::intravisit::walk_item::he9d61edd2c8d86e4
  47:     0x7ff540f2b59b - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item::h913aa09c54c17ff3
  48:     0x7ff540f2daa0 - <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_mod::h02594b4f3e3330ae
  49:     0x7ff540e7467e - rustc::hir::intravisit::walk_crate::hb1af66e338bade00
  50:     0x7ff540f34dca - rustc::lint::context::check_crate::h59d58a2726a89b10
  51:     0x7ff541c93bb5 - rustc::util::common::time::h37c011639b879a10
  52:     0x7ff541d19955 - rustc::ty::context::tls::enter_context::h6950822dd08f2c59
  53:     0x7ff541cd5a91 - <std::thread::local::LocalKey<T>>::with::h42405c22a7b681ca
  54:     0x7ff541d441c7 - rustc::ty::context::TyCtxt::create_and_enter::ha95c55f91512e935
  55:     0x7ff541c7ce2e - rustc_driver::driver::compile_input::hcd247e03696e3fb1
  56:     0x7ff541d29f09 - rustc_driver::run_compiler_with_pool::h9471c56f5248e8fa
  57:     0x7ff541c7aa6b - rustc_driver::driver::spawn_thread_pool::hc38d4bef06adb0b4
  58:     0x7ff541d28f47 - rustc_driver::run_compiler::h9d2a717d593d7246
  59:     0x564551dc5de7 - clippy_driver::main::{{closure}}::h3070fae3d07d268d
                               at src/driver.rs:157
  60:     0x564551dc2879 - rustc_driver::run::{{closure}}::{{closure}}::h94b4b5494fb3abc8
                               at librustc_driver/lib.rs:189
  61:     0x564551df330f - <scoped_tls::ScopedKey<T>>::set::hab01b7f36a3696f3
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-0.1.2/src/lib.rs:155
  62:     0x564551dc66aa - syntax::with_globals::{{closure}}::hf4f09544896319d8
                               at libsyntax/lib.rs:106
  63:     0x564551df3249 - <scoped_tls::ScopedKey<T>>::set::h0ce8185ea1bf92df
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-0.1.2/src/lib.rs:155
  64:     0x564551dc6621 - syntax::with_globals::h96b219aa59789cfd
                               at libsyntax/lib.rs:105
  65:     0x564551dc2848 - rustc_driver::run::{{closure}}::hb5011e7d2a16f523
                               at librustc_driver/lib.rs:188
  66:     0x564551dc3838 - rustc_driver::monitor::{{closure}}::hc025465fd14d7f73
                               at librustc_driver/lib.rs:1660
  67:     0x564551dccf18 - <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once::h09f4ddee2a6c4f27
                               at libstd/panic.rs:313
  68:     0x564551df8a6a - std::panicking::try::do_call::h40a0b1fe1bed7da5
                               at libstd/panicking.rs:310
  69:     0x7ff53ef49d89 - __rust_maybe_catch_panic
                               at libpanic_unwind/lib.rs:102
  70:     0x564551df88f4 - std::panicking::try::h7aa93e0933be93fc
                               at libstd/panicking.rs:289
  71:     0x564551dccf58 - std::panic::catch_unwind::he9bd4dd23dea76ba
                               at libstd/panic.rs:392
  72:     0x564551dc24a8 - rustc_driver::in_named_rustc_thread::hde5420c565dbaaff
                               at librustc_driver/lib.rs:1574
  73:     0x564551dc1ed0 - rustc_driver::in_rustc_thread::h716d001069807035
                               at librustc_driver/lib.rs:1585
  74:     0x564551dc2c58 - rustc_driver::monitor::h8b84895cf4afea9a
                               at librustc_driver/lib.rs:1659
  75:     0x564551dc27e8 - rustc_driver::run::h9f2884da1af3e206
                               at librustc_driver/lib.rs:187
  76:     0x564551dff5ee - clippy_driver::main::h27bda5ed578684af
                               at src/driver.rs:37
  77:     0x564551dc1e6f - std::rt::lang_start::{{closure}}::h79cbda49d6d4a726
                               at libstd/rt.rs:74
  78:     0x7ff53ef3bf52 - std::panicking::try::do_call::ha2b0c74d7054d335
                               at libstd/rt.rs:59
                               at libstd/panicking.rs:310
  79:     0x7ff53ef49d89 - __rust_maybe_catch_panic
                               at libpanic_unwind/lib.rs:102
  80:     0x7ff53ef1003a - std::rt::lang_start_internal::h9638620ca7e1b9bd
                               at libstd/panicking.rs:289
                               at libstd/panic.rs:392
                               at libstd/rt.rs:58
  81:     0x564551dc1e48 - std::rt::lang_start::h2fc573a103e6ac9a
                               at libstd/rt.rs:74
  82:     0x564551dff669 - main
  83:     0x7ff53ec91222 - __libc_start_main
  84:     0x564551dad02d - _start
  85:                0x0 - <unknown>
query stack during panic:
end of query stack

error: internal compiler error: unexpected panic

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 1.31.0-nightly (77af31408 2018-10-11) running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental -C target-cpu=native --crate-type lib

note: some of the compiler flags provided by cargo are hidden

error: Could not compile `goblin`.

Caused by:
  process didn't exit successfully: `/home/matthias/vcs/github/rust-clippy/target/debug/clippy-driver rustc --crate-name goblin src/lib.rs --color always --crate-type lib --emit=dep-info,metadata -C debuginfo=2 --cfg 'feature="alloc"' --cfg 'feature="archive"' --cfg 'feature="default"' --cfg 'feature="elf32"' --cfg 'feature="elf64"' --cfg 'feature="endian_fd"' --cfg 'feature="log"' --cfg 'feature="mach32"' --cfg 'feature="mach64"' --cfg 'feature="pe32"' --cfg 'feature="pe64"' --cfg 'feature="scroll"' --cfg 'feature="std"' -C metadata=444c2f72a8efe6ed -C extra-filename=-444c2f72a8efe6ed --out-dir /tmp/goblin/target/debug/deps -C incremental=/tmp/goblin/target/debug/incremental -L dependency=/tmp/goblin/target/debug/deps --extern log=/tmp/goblin/target/debug/deps/liblog-997e20cf8ae6acad.rmeta --extern plain=/tmp/goblin/target/debug/deps/libplain-c0f5275e9e78a53e.rmeta --extern scroll=/tmp/goblin/target/debug/deps/libscroll-a5ca24c4ef6ea987.rmeta -C target-cpu=native` (exit code: 101)

Found via #3142

[shssoichiro]

Looking into this. It's turning out to be a deep rabbit hole. I'll continue to test.

[shssoichiro]

I've found that this crash has probably always existed. It is reproducible with the rustc and clippy version shipped with rustup stable. Still trying to determine the root cause.

[shssoichiro]

It looks like the crash is occurring because clippy is trying to create a suggestion with 2 span replacements, but because the lint triggers within a proc macro, the compiler tries to apply the replacement to the same span, and crashes.

What is the typical way of handling these scenarios? Is there a mechanism within clippy to ignore lints within macro expansions? If we removed the suggestion, it would resolve the crash, but we wouldn't want to remove the suggestion in cases where it can be applied properly.

[phansch]

@shssoichiro For ignoring macro expansions, you can use the in_macro() function.

It depends on the specific case whether we want to remove the suggestion or not. I would say fixing the crash is more important than suggestion correctness. We can always file a separate issue to work on the suggestion in a second step.

Did you find a small code snippet that reproduces the crash?

[shssoichiro]

Yes, I do have a minified test case which I'll include in the PR.