ICE: thread 'rustc' panicked at 'index out of bounds: the len is 0 but the index is 0', clippy_lints/src/methods/unnecessary_literal_unwrap.rs:98:36

[y21]

Summary

An ICE spotted in the wild: https://github.com/hash-org/hashc/actions/runs/5444774442/jobs/9903084327#step:8:132

Small reproducer:

fn main() {
  None::<i32>.unwrap_or_default();
}

Version

rustc 1.72.0-nightly (5bd28f5ea 2023-06-28)
binary: rustc
commit-hash: 5bd28f5eac1ba3569bfa8d49ec3f5acbdfdff7a0
commit-date: 2023-06-28
host: x86_64-unknown-linux-gnu
release: 1.72.0-nightly
LLVM version: 16.0.5

Error output

Backtrace

thread 'rustc' panicked at 'index out of bounds: the len is 0 but the index is 0', src/tools/clippy/clippy_lints/src/methods/unnecessary_literal_unwrap.rs:81:36
stack backtrace:
 0:     0x7fdf73925e61 - std::backtrace_rs::backtrace::libunwind::trace::h5ce8db1912fa0c1f
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
 1:     0x7fdf73925e61 - std::backtrace_rs::backtrace::trace_unsynchronized::he4bbc2b1009275a2
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
 2:     0x7fdf73925e61 - std::sys_common::backtrace::_print_fmt::h850cfb06bfa31ba4
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/sys_common/backtrace.rs:65:5
 3:     0x7fdf73925e61 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h1b7c35c1f6d053d9
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/sys_common/backtrace.rs:44:22
 4:     0x7fdf7398763f - core::fmt::rt::Argument::fmt::hec2555f32021416c
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/core/src/fmt/rt.rs:138:9
 5:     0x7fdf7398763f - core::fmt::write::hd6cf2d22c3c018cc
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/core/src/fmt/mod.rs:1094:21
 6:     0x7fdf73918997 - std::io::Write::write_fmt::hedf74eca7c2ca256
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/io/mod.rs:1714:15
 7:     0x7fdf73925c75 - std::sys_common::backtrace::_print::hf4e3d9b927e4f737
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/sys_common/backtrace.rs:47:5
 8:     0x7fdf73925c75 - std::sys_common::backtrace::print::h8564480b3c5e7d68
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/sys_common/backtrace.rs:34:9
 9:     0x7fdf73928a23 - std::panicking::default_hook::{{closure}}::h18d3d1ae568fd983
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/panicking.rs:269:22
10:     0x7fdf739287b4 - std::panicking::default_hook::h94c1f863d9937cf7
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/panicking.rs:288:9
11:     0x7fdf76c9079b - <rustc_driver_impl[c923a25382e6f86e]::install_ice_hook::{closure#0} as core[5b52bdd80f2b5198]::ops::function::FnOnce<(&core[5b52bdd80f2b5198]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
12:     0x7fdf7392924e - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hed90b769a5ccdc9c
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/alloc/src/boxed.rs:2024:9
13:     0x7fdf7392924e - std::panicking::rust_panic_with_hook::ha95aefb921a95644
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/panicking.rs:709:13
14:     0x7fdf73928fd7 - std::panicking::begin_panic_handler::{{closure}}::h091d95547ecdbca1
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/panicking.rs:597:13
15:     0x7fdf73926296 - std::sys_common::backtrace::__rust_end_short_backtrace::h648bf79e56cc718c
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/sys_common/backtrace.rs:151:18
16:     0x7fdf73928d22 - rust_begin_unwind
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/panicking.rs:593:5
17:     0x7fdf73983893 - core::panicking::panic_fmt::ha9acf6905b52ba6c
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/core/src/panicking.rs:67:14
18:     0x7fdf739839f2 - core::panicking::panic_bounds_check::haae8c7ca27be81d9
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/core/src/panicking.rs:162:5
19:     0x565078a0bb78 - <clippy_utils[dc0267f2510d6c15]::diagnostics::span_lint_and_then<rustc_lint[e582040643e9114c]::context::LateContext, rustc_span[5216bc3763fa4dcf]::span_encoding::Span, clippy_lints[41dd6ee57012f9ce]::methods::unnecessary_literal_unwrap::check::{closure#1}>::{closure#0} as core[5b52bdd80f2b5198]::ops::function::FnOnce<(&mut rustc_errors[5c6030d8c3858c73]::diagnostic_builder::DiagnosticBuilder<()>,)>>::call_once::{shim:vtable#0}
20:     0x5650789fde22 - rustc_middle[a1dccb58286d3ba8]::lint::struct_lint_level::struct_lint_level_impl::<alloc[27c9fe8bf6a2e6a2]::string::String>
21:     0x5650789ef424 - rustc_middle[a1dccb58286d3ba8]::lint::struct_lint_level::<alloc[27c9fe8bf6a2e6a2]::string::String, clippy_utils[dc0267f2510d6c15]::diagnostics::span_lint_and_then<rustc_lint[e582040643e9114c]::context::LateContext, rustc_span[5216bc3763fa4dcf]::span_encoding::Span, clippy_lints[41dd6ee57012f9ce]::methods::unnecessary_literal_unwrap::check::{closure#1}>::{closure#0}>
22:     0x5650789b7f2c - <rustc_lint[e582040643e9114c]::context::LateContext as rustc_lint[e582040643e9114c]::context::LintContext>::struct_span_lint::<rustc_span[5216bc3763fa4dcf]::span_encoding::Span, alloc[27c9fe8bf6a2e6a2]::string::String, clippy_utils[dc0267f2510d6c15]::diagnostics::span_lint_and_then<rustc_lint[e582040643e9114c]::context::LateContext, rustc_span[5216bc3763fa4dcf]::span_encoding::Span, clippy_lints[41dd6ee57012f9ce]::methods::unnecessary_literal_unwrap::check::{closure#1}>::{closure#0}>
23:     0x5650787c3c29 - clippy_lints[41dd6ee57012f9ce]::methods::unnecessary_literal_unwrap::check
24:     0x5650787fad32 - <clippy_lints[41dd6ee57012f9ce]::methods::Methods>::check_methods
25:     0x5650787f89e8 - <clippy_lints[41dd6ee57012f9ce]::methods::Methods as rustc_lint[e582040643e9114c]::passes::LateLintPass>::check_expr
26:     0x7fdf770c70a6 - <rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass as rustc_lint[e582040643e9114c]::passes::LateLintPass>::check_expr
27:     0x7fdf77061a96 - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
28:     0x7fdf7706235c - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_expr
29:     0x7fdf7703224b - rustc_hir[655fc525311d4d25]::intravisit::walk_block::<rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass>>
30:     0x7fdf77062469 - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_block
31:     0x7fdf77061aa1 - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
32:     0x7fdf7706235c - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_expr
33:     0x7fdf770627b5 - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_nested_body
34:     0x7fdf7706299a - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_fn
35:     0x7fdf77033c23 - rustc_hir[655fc525311d4d25]::intravisit::walk_item::<rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass>>
36:     0x7fdf770630ef - <rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass> as rustc_hir[655fc525311d4d25]::intravisit::Visitor>::visit_nested_item
37:     0x7fdf770334a8 - rustc_hir[655fc525311d4d25]::intravisit::walk_mod::<rustc_lint[e582040643e9114c]::late::LateContextAndPass<rustc_lint[e582040643e9114c]::late::RuntimeCombinedLateLintPass>>
38:     0x7fdf760b125e - rustc_lint[e582040643e9114c]::late::late_lint_crate::<rustc_lint[e582040643e9114c]::BuiltinCombinedLateLintPass>
39:     0x7fdf760b0678 - <rustc_session[17f2309dba35d20d]::session::Session>::time::<(), rustc_lint[e582040643e9114c]::late::check_crate<rustc_lint[e582040643e9114c]::BuiltinCombinedLateLintPass, rustc_interface[f8db984e9bc2c23a]::passes::analysis::{closure#5}::{closure#1}::{closure#2}::{closure#0}::{closure#0}>::{closure#0}::{closure#0}>
40:     0x7fdf760b0513 - <rustc_session[17f2309dba35d20d]::session::Session>::time::<(), rustc_interface[f8db984e9bc2c23a]::passes::analysis::{closure#5}::{closure#1}::{closure#2}::{closure#0}>
41:     0x7fdf760b00c9 - std[1b53aa499255e0c]::panicking::try::<(), core[5b52bdd80f2b5198]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[f8db984e9bc2c23a]::passes::analysis::{closure#5}::{closure#1}>>
42:     0x7fdf760af4d0 - <rustc_session[17f2309dba35d20d]::session::Session>::time::<(), rustc_interface[f8db984e9bc2c23a]::passes::analysis::{closure#5}>
43:     0x7fdf760ad157 - rustc_interface[f8db984e9bc2c23a]::passes::analysis
44:     0x7fdf76134d4a - rustc_query_impl[35d2e235666c19ba]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[35d2e235666c19ba]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a1dccb58286d3ba8]::query::erase::Erased<[u8; 1usize]>>
45:     0x7fdf76134d39 - <rustc_query_impl[35d2e235666c19ba]::query_impl::analysis::dynamic_query::{closure#2} as core[5b52bdd80f2b5198]::ops::function::FnOnce<(rustc_middle[a1dccb58286d3ba8]::ty::context::TyCtxt, ())>>::call_once
46:     0x7fdf762d9368 - rustc_query_system[fec6f493e9650b57]::query::plumbing::try_execute_query::<rustc_query_impl[35d2e235666c19ba]::DynamicConfig<rustc_query_system[fec6f493e9650b57]::query::caches::SingleCache<rustc_middle[a1dccb58286d3ba8]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[35d2e235666c19ba]::plumbing::QueryCtxt, false>
47:     0x7fdf762d9139 - rustc_query_impl[35d2e235666c19ba]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
48:     0x7fdf75e1ffc5 - <rustc_middle[a1dccb58286d3ba8]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[c923a25382e6f86e]::run_compiler::{closure#1}::{closure#2}::{closure#4}, core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>>
49:     0x7fdf75e1f5f1 - <rustc_interface[f8db984e9bc2c23a]::interface::Compiler>::enter::<rustc_driver_impl[c923a25382e6f86e]::run_compiler::{closure#1}::{closure#2}, core[5b52bdd80f2b5198]::result::Result<core[5b52bdd80f2b5198]::option::Option<rustc_interface[f8db984e9bc2c23a]::queries::Linker>, rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>>
50:     0x7fdf75e16115 - rustc_span[5216bc3763fa4dcf]::set_source_map::<core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>, rustc_interface[f8db984e9bc2c23a]::interface::run_compiler<core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>, rustc_driver_impl[c923a25382e6f86e]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
51:     0x7fdf75e15536 - <scoped_tls[d2d50f9e0583bf74]::ScopedKey<rustc_span[5216bc3763fa4dcf]::SessionGlobals>>::set::<rustc_interface[f8db984e9bc2c23a]::interface::run_compiler<core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>, rustc_driver_impl[c923a25382e6f86e]::run_compiler::{closure#1}>::{closure#0}, core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>>
52:     0x7fdf75e14afc - std[1b53aa499255e0c]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[f8db984e9bc2c23a]::util::run_in_thread_pool_with_globals<rustc_interface[f8db984e9bc2c23a]::interface::run_compiler<core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>, rustc_driver_impl[c923a25382e6f86e]::run_compiler::{closure#1}>::{closure#0}, core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>>
53:     0x7fdf764cabbe - <<std[1b53aa499255e0c]::thread::Builder>::spawn_unchecked_<rustc_interface[f8db984e9bc2c23a]::util::run_in_thread_pool_with_globals<rustc_interface[f8db984e9bc2c23a]::interface::run_compiler<core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>, rustc_driver_impl[c923a25382e6f86e]::run_compiler::{closure#1}>::{closure#0}, core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[5b52bdd80f2b5198]::result::Result<(), rustc_span[5216bc3763fa4dcf]::ErrorGuaranteed>>::{closure#1} as core[5b52bdd80f2b5198]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
54:     0x7fdf739336c5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hdbc0aef15db98218
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/alloc/src/boxed.rs:2010:9
55:     0x7fdf739336c5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h8ad1d8fc5d57372a
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/alloc/src/boxed.rs:2010:9
56:     0x7fdf739336c5 - std::sys::unix::thread::Thread::new::thread_start::h94617354d8b43e85
                             at /rustc/839e9a6e1210934fd24b15548b811a97c77138fc/library/std/src/sys/unix/thread.rs:108:17
57:     0x7fdf737f4609 - start_thread
58:     0x7fdf735c8133 - clone
59:                0x0 - <unknown>

error: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: rustc 1.72.0-nightly (839e9a6e1 2023-07-02) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type bin -C embed-bitcode=no -C codegen-units=1 -C debuginfo=2

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

query stack during panic:
#0 [analysis] running analysis passes on this crate
end of query stack
note: Clippy version: clippy 0.1.72 (839e9a6 2023-07-02)