warning: the feature `guard_patterns` is incomplete and may not be safe to use and/or cause compiler crashes --> /tmp/icemaker_global_tempdir.lrrS5NseB5VV/rustc_testrunner_tmpdir_reporting.IHAQeISeUx35/mvce.rs:1:12 | 1 | #![feature(guard_patterns)] | ^^^^^^^^^^^^^^ | = note: see issue #129967 <https://github.com/rust-lang/rust/issues/129967> for more information = note: `#[warn(incomplete_features)]` on by default warning: unreachable pattern --> /tmp/icemaker_global_tempdir.lrrS5NseB5VV/rustc_testrunner_tmpdir_reporting.IHAQeISeUx35/mvce.rs:6:9 | 5 | (_ if { let main = false; main },) => {} | ---------------------------------- matches any value 6 | _ => {} | ^ no value can reach this | = note: `#[warn(unreachable_patterns)]` (part of `#[warn(unused)]`) on by default warning: variable `main` is assigned to, but never used --> /tmp/icemaker_global_tempdir.lrrS5NseB5VV/rustc_testrunner_tmpdir_reporting.IHAQeISeUx35/mvce.rs:5:21 | 5 | (_ if { let main = false; main },) => {} | ^^^^ | = note: consider using `_main` instead = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default warning: 3 warnings emitted note: no errors encountered even though delayed bugs were created note: those delayed bugs will now be shown as internal compiler errors error: internal compiler error: no successor | = note: delayed at compiler/rustc_passes/src/liveness.rs:575:35 0: <rustc_errors::DiagCtxtInner>::emit_diagnostic 1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic 2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee 3: <rustc_passes::liveness::Liveness>::report_unused 4: rustc_hir::intravisit::walk_block::<rustc_passes::liveness::Liveness> 5: <rustc_passes::liveness::Liveness as rustc_hir::intravisit::Visitor>::visit_expr 6: <rustc_passes::liveness::Liveness as rustc_hir::intravisit::Visitor>::visit_pat 7: <rustc_passes::liveness::Liveness as rustc_hir::intravisit::Visitor>::visit_expr 8: rustc_hir::intravisit::walk_block::<rustc_passes::liveness::Liveness> 9: <rustc_passes::liveness::Liveness as rustc_hir::intravisit::Visitor>::visit_expr 10: rustc_passes::liveness::check_liveness 11: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_liveness::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>> 12: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 0]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> 13: rustc_query_impl::query_impl::check_liveness::get_query_non_incr::__rust_end_short_backtrace 14: rustc_mir_build::builder::build_mir 15: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_built::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>> 16: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> 17: rustc_query_impl::query_impl::mir_built::get_query_non_incr::__rust_end_short_backtrace 18: rustc_mir_build::check_unsafety::check_unsafety 19: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_unsafety::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>> 20: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 0]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> 21: rustc_query_impl::query_impl::check_unsafety::get_query_non_incr::__rust_end_short_backtrace 22: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface::passes::run_required_analyses::{closure#1}::{closure#0}>::{closure#0} 23: rustc_interface::passes::analysis 24: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>> 25: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> 26: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace 27: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0} 28: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1} 29: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()> 30: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 31: std::sys::pal::unix::thread::Thread::new::thread_start 32: <unknown> 33: <unknown> 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: please make sure that you have updated to the latest nightly note: rustc 1.91.0-nightly (f4665ab83 2025-09-10) running on x86_64-unknown-linux-gnu query stack during panic: end of query stack