ICE: Err on value: "core", map_unit_fn.rs

[matthiaskrgr]

Code

#![crate_type = "lib"]
fn _y() {
    vec![42].iter().map(drop);
}

Meta

rustc --version --verbose:

rustc 1.70.0-nightly (22f247c6f 2023-03-13)
binary: rustc
commit-hash: 22f247c6f3ed388cb702d01c2ff27da658a8b353
commit-date: 2023-03-13
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 15.0.7

Error output

<output>

Backtrace

warning: unused `Map` that must be used
 --> treereduce.out:3:5
  |
3 |     vec![42].iter().map(drop);
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: iterators are lazy and do nothing unless consumed
  = note: `#[warn(unused_must_use)]` on by default

thread 'rustc' panicked at 'called `Result::unwrap()` on an `Err` value: "core"', compiler/rustc_lint/src/map_unit_fn.rs:67:78
stack backtrace:
   0:     0x7f010976651a - std::backtrace_rs::backtrace::libunwind::trace::h1ac6254167c780d9
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f010976651a - std::backtrace_rs::backtrace::trace_unsynchronized::hec2af85915e24f36
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f010976651a - std::sys_common::backtrace::_print_fmt::h58a4e3535fcce206
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7f010976651a - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h5107e13758b8321c
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f01097c9c5e - core::fmt::write::h2e851dc027730d81
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/core/src/fmt/mod.rs:1232:17
   5:     0x7f0109759375 - std::io::Write::write_fmt::hca00074de9f85084
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/io/mod.rs:1684:15
   6:     0x7f01097662e5 - std::sys_common::backtrace::_print::h870053c845cddf24
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:47:5
   7:     0x7f01097662e5 - std::sys_common::backtrace::print::hb56add862f96c5fd
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:34:9
   8:     0x7f010976905f - std::panicking::default_hook::{{closure}}::h636d4ba3ff8fdc46
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:271:22
   9:     0x7f0109768d9b - std::panicking::default_hook::hf29b58145ee6e43c
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:290:9
  10:     0x7f010ca580c5 - <rustc_driver_impl[74350ec99973fded]::DEFAULT_HOOK::{closure#0}::{closure#0} as core[2011dc7817943e09]::ops::function::FnOnce<(&core[2011dc7817943e09]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  11:     0x7f010976989d - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h7342d57f33f6634f
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/alloc/src/boxed.rs:2002:9
  12:     0x7f010976989d - std::panicking::rust_panic_with_hook::hbf9ef936d990c16f
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:696:13
  13:     0x7f0109769619 - std::panicking::begin_panic_handler::{{closure}}::h6be6433dcb901f4b
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:583:13
  14:     0x7f0109766986 - std::sys_common::backtrace::__rust_end_short_backtrace::h802b6104a4d80829
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys_common/backtrace.rs:150:18
  15:     0x7f0109769322 - rust_begin_unwind
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/panicking.rs:579:5
  16:     0x7f01097c5fb3 - core::panicking::panic_fmt::hf7a8a88b9669732e
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/core/src/panicking.rs:64:14
  17:     0x7f01097c6543 - core::result::unwrap_failed::hcd86a721526c2121
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/core/src/result.rs:1750:5
  18:     0x7f010b3b6c44 - <rustc_lint[c11cb6a8cfa5f7c9]::late::LateContextAndPass<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedModuleLateLintPass> as rustc_hir[ca07edd3831bb6e2]::intravisit::Visitor>::visit_stmt
  19:     0x7f010b3abe5e - <rustc_lint[c11cb6a8cfa5f7c9]::late::LateContextAndPass<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedModuleLateLintPass> as rustc_hir[ca07edd3831bb6e2]::intravisit::Visitor>::visit_expr
  20:     0x7f010b8b79ab - rustc_hir[ca07edd3831bb6e2]::intravisit::walk_fn::<rustc_lint[c11cb6a8cfa5f7c9]::late::LateContextAndPass<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedModuleLateLintPass>>
  21:     0x7f010b8afe63 - rustc_hir[ca07edd3831bb6e2]::intravisit::walk_item::<rustc_lint[c11cb6a8cfa5f7c9]::late::LateContextAndPass<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedModuleLateLintPass>>
  22:     0x7f010b8af599 - rustc_hir[ca07edd3831bb6e2]::intravisit::walk_mod::<rustc_lint[c11cb6a8cfa5f7c9]::late::LateContextAndPass<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedModuleLateLintPass>>
  23:     0x7f010b8aef13 - rustc_lint[c11cb6a8cfa5f7c9]::late::late_lint_mod::<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedModuleLateLintPass>
  24:     0x7f010b8aed0c - rustc_lint[c11cb6a8cfa5f7c9]::lint_mod
  25:     0x7f010c0988ce - rustc_query_system[f881c7f40ee7dcf0]::query::plumbing::try_execute_query::<rustc_query_impl[eb95ff51c492efdd]::queries::lint_mod, rustc_query_impl[eb95ff51c492efdd]::plumbing::QueryCtxt>
  26:     0x7f010c098453 - <rustc_query_impl[eb95ff51c492efdd]::Queries as rustc_middle[eaae5d2a0b8f0144]::ty::query::QueryEngine>::lint_mod
  27:     0x7f010ae3dfe8 - rustc_data_structures[75b47a18491287a9]::sync::par_for_each_in::<&[rustc_hir[ca07edd3831bb6e2]::hir_id::OwnerId], <rustc_middle[eaae5d2a0b8f0144]::hir::map::Map>::par_for_each_module<rustc_lint[c11cb6a8cfa5f7c9]::late::check_crate<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedLateLintPass, rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#6}::{closure#1}::{closure#2}::{closure#0}::{closure#0}>::{closure#1}::{closure#0}::{closure#0}>::{closure#0}>
  28:     0x7f010ae3dd6e - <rustc_session[a360c2d099171c08]::session::Session>::time::<(), rustc_lint[c11cb6a8cfa5f7c9]::late::check_crate<rustc_lint[c11cb6a8cfa5f7c9]::BuiltinCombinedLateLintPass, rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#6}::{closure#1}::{closure#2}::{closure#0}::{closure#0}>::{closure#1}::{closure#0}>
  29:     0x7f010ae3d79f - <rustc_session[a360c2d099171c08]::session::Session>::time::<(), rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#6}::{closure#1}::{closure#2}::{closure#0}>
  30:     0x7f010ae3d418 - <core[2011dc7817943e09]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#6}::{closure#1}> as core[2011dc7817943e09]::ops::function::FnOnce<()>>::call_once
  31:     0x7f010ae3ce53 - <rustc_session[a360c2d099171c08]::session::Session>::time::<(), rustc_interface[ceda1fd77ec39e1b]::passes::analysis::{closure#6}>
  32:     0x7f010ae3b27a - rustc_interface[ceda1fd77ec39e1b]::passes::analysis
  33:     0x7f010c276a4c - rustc_query_system[f881c7f40ee7dcf0]::query::plumbing::try_execute_query::<rustc_query_impl[eb95ff51c492efdd]::queries::analysis, rustc_query_impl[eb95ff51c492efdd]::plumbing::QueryCtxt>
  34:     0x7f010c276740 - <rustc_query_impl[eb95ff51c492efdd]::Queries as rustc_middle[eaae5d2a0b8f0144]::ty::query::QueryEngine>::analysis
  35:     0x7f010c09f789 - <rustc_middle[eaae5d2a0b8f0144]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}::{closure#2}::{closure#4}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>
  36:     0x7f010bc8ef08 - rustc_span[18b84908941c7cdf]::with_source_map::<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_interface[ceda1fd77ec39e1b]::interface::run_compiler<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  37:     0x7f010bc8616c - std[1337fb43929788f1]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[ceda1fd77ec39e1b]::util::run_in_thread_pool_with_globals<rustc_interface[ceda1fd77ec39e1b]::interface::run_compiler<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}>::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>
  38:     0x7f010bc85b9a - <<std[1337fb43929788f1]::thread::Builder>::spawn_unchecked_<rustc_interface[ceda1fd77ec39e1b]::util::run_in_thread_pool_with_globals<rustc_interface[ceda1fd77ec39e1b]::interface::run_compiler<core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>, rustc_driver_impl[74350ec99973fded]::run_compiler::{closure#1}>::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2011dc7817943e09]::result::Result<(), rustc_span[18b84908941c7cdf]::ErrorGuaranteed>>::{closure#1} as core[2011dc7817943e09]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  39:     0x7f0109773793 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h7e0474dd3b8659fa
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/alloc/src/boxed.rs:1988:9
  40:     0x7f0109773793 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::heb8c41cf543a5c11
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/alloc/src/boxed.rs:1988:9
  41:     0x7f0109773793 - std::sys::unix::thread::Thread::new::thread_start::hc791abe67253fe06
                               at /rustc/22f247c6f3ed388cb702d01c2ff27da658a8b353/library/std/src/sys/unix/thread.rs:108:17
  42:     0x7f0109505bb5 - <unknown>
  43:     0x7f0109587d90 - <unknown>
  44:                0x0 - <unknown>

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

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.70.0-nightly (22f247c6f 2023-03-13) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [lint_mod] linting top-level module
#1 [analysis] running analysis passes on this crate
end of query stack
warning: 1 warning emitted

[compiler-errors]

This broke in #107890, cc @obeis