[ICE]: not yet implemented: Iterator is not yet const

error[E0658]: const block items are experimental
 --> /tmp/icemaker_global_tempdir.tBaX7hGcZGa3/rustc_testrunner_tmpdir_reporting.Qb7KcQ0jAzdE/mvce.rs:1:1
  |
1 | const { for _ in 1.. {} }
  | ^^^^^
  |
  = note: see issue #149226 <https://github.com/rust-lang/rust/issues/149226> for more information
  = help: add `#![feature(const_block_items)]` to the crate attributes to enable
  = note: this compiler was built on 2026-01-31; consider upgrading it if it is out of date

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.tBaX7hGcZGa3/rustc_testrunner_tmpdir_reporting.Qb7KcQ0jAzdE/mvce.rs:1:26
  |
1 | const { for _ in 1.. {} }
  |                          ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.tBaX7hGcZGa3/rustc_testrunner_tmpdir_reporting.Qb7KcQ0jAzdE/mvce.rs`


thread 'rustc' (840458) panicked at /rustc-dev/1e9be1b77fe89d9757d6179973b2fc970c6e83b7/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs:358:9:
not yet implemented: Iterator is not yet const
stack backtrace:
   0:     0x7f9fe66442ab - <<std[a1fadf1b190cf199]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[60f2ed223aee2384]::fmt::Display>::fmt
   1:     0x7f9fe6c0ef88 - core[60f2ed223aee2384]::fmt::write
   2:     0x7f9fe665b146 - <std[a1fadf1b190cf199]::sys::stdio::unix::Stderr as std[a1fadf1b190cf199]::io::Write>::write_fmt
   3:     0x7f9fe661a358 - std[a1fadf1b190cf199]::panicking::default_hook::{closure#0}
   4:     0x7f9fe6637673 - std[a1fadf1b190cf199]::panicking::default_hook
   5:     0x7f9fe560d52d - std[a1fadf1b190cf199]::panicking::update_hook::<alloc[a68f8e530fb470c9]::boxed::Box<rustc_driver_impl[bc96bfd14d55c39f]::install_ice_hook::{closure#1}>>::{closure#0}
   6:     0x7f9fe6637952 - std[a1fadf1b190cf199]::panicking::panic_with_hook
   7:     0x7f9fe661a44a - std[a1fadf1b190cf199]::panicking::panic_handler::{closure#0}
   8:     0x7f9fe660e989 - std[a1fadf1b190cf199]::sys::backtrace::__rust_end_short_backtrace::<std[a1fadf1b190cf199]::panicking::panic_handler::{closure#0}, !>
   9:     0x7f9fe661be7d - __rustc[dd30a9ec31dc635b]::rust_begin_unwind
  10:     0x7f9fe32fce7c - core[60f2ed223aee2384]::panicking::panic_fmt
  11:     0x7f9fe81731ca - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::assemble_and_evaluate_candidates::<rustc_type_ir[4cf2fa28c2db9892]::predicate::HostEffectPredicate<rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>
  12:     0x7f9fe817220c - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::compute_host_effect_goal
  13:     0x7f9fe7ad07f1 - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::search_graph::SearchGraphDelegate<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate> as rustc_type_ir[4cf2fa28c2db9892]::search_graph::Delegate>::compute_goal::{closure#0}
  14:     0x7f9fe778aaae - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::evaluate_goal_raw
  15:     0x7f9fe7795334 - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::try_evaluate_added_goals
  16:     0x7f9fe77ae04c - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::evaluate_added_goals_and_make_canonical_response
  17:     0x7f9fe63cfd07 - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::assemble_impl_candidates::<rustc_type_ir[4cf2fa28c2db9892]::predicate::HostEffectPredicate<rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::{closure#0}
  18:     0x7f9fe8173f13 - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::assemble_and_evaluate_candidates::<rustc_type_ir[4cf2fa28c2db9892]::predicate::HostEffectPredicate<rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>
  19:     0x7f9fe817220c - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::compute_host_effect_goal
  20:     0x7f9fe7ad07f1 - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::search_graph::SearchGraphDelegate<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate> as rustc_type_ir[4cf2fa28c2db9892]::search_graph::Delegate>::compute_goal::{closure#0}
  21:     0x7f9fe778aaae - <rustc_next_trait_solver[c27f26f29963ae7e]::solve::eval_ctxt::EvalCtxt<rustc_trait_selection[d1e3867d294e5bb5]::solve::delegate::SolverDelegate, rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>>::evaluate_goal_raw
  22:     0x7f9fe779a07c - <rustc_trait_selection[d1e3867d294e5bb5]::solve::fulfill::FulfillmentCtxt<rustc_infer[25833ecceaf82304]::traits::engine::ScrubbedTraitError> as rustc_infer[25833ecceaf82304]::traits::engine::TraitEngine<rustc_infer[25833ecceaf82304]::traits::engine::ScrubbedTraitError>>::evaluate_obligations_error_on_ambiguity
  23:     0x7f9fe7b4ddc0 - <rustc_const_eval[d2ba75e3b2a83d67]::check_consts::check::Checker as rustc_middle[984b58fac644d3ae]::mir::visit::Visitor>::visit_terminator
  24:     0x7f9fe78a3799 - <rustc_const_eval[d2ba75e3b2a83d67]::check_consts::check::Checker as rustc_middle[984b58fac644d3ae]::mir::visit::Visitor>::visit_basic_block_data
  25:     0x7f9fe78a327a - <rustc_const_eval[d2ba75e3b2a83d67]::check_consts::check::Checker>::check_body
  26:     0x7f9fe789ee32 - rustc_mir_transform[4dbfb044d0754d44]::mir_const_qualif
  27:     0x7f9fe789ecb1 - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_const_qualif::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 4usize]>>
  28:     0x7f9fe789e2e8 - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_query_system[cd9df96c377c45f]::query::caches::DefIdCache<rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 4usize]>>, false, false, false>, false>
  29:     0x7f9fe789e046 - rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_const_qualif::get_query_non_incr::__rust_end_short_backtrace
  30:     0x7f9fe78b4c08 - rustc_mir_transform[4dbfb044d0754d44]::mir_promoted
  31:     0x7f9fe78b37a0 - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_promoted::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 16usize]>>
  32:     0x7f9fe7558b36 - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_data_structures[32839d0f870d4629]::vec_cache::VecCache<rustc_span[48b98895bb5be65f]::def_id::LocalDefId, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 16usize]>, rustc_query_system[cd9df96c377c45f]::dep_graph::graph::DepNodeIndex>, false, false, false>, false>
  33:     0x7f9fe75586cc - rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_promoted::get_query_non_incr::__rust_end_short_backtrace
  34:     0x7f9fe6d89f80 - rustc_borrowck[fc03e7d2671a42b]::mir_borrowck
  35:     0x7f9fe6d89ed9 - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_borrowck::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 8usize]>>
  36:     0x7f9fe6d8c072 - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_data_structures[32839d0f870d4629]::vec_cache::VecCache<rustc_hir_id[d1ce817282485795]::OwnerId, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 8usize]>, rustc_query_system[cd9df96c377c45f]::dep_graph::graph::DepNodeIndex>, false, false, false>, false>
  37:     0x7f9fe6d874a3 - rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  38:     0x7f9fe79d161c - rustc_mir_transform[4dbfb044d0754d44]::mir_drops_elaborated_and_const_checked
  39:     0x7f9fe79d0b23 - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_drops_elaborated_and_const_checked::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 8usize]>>
  40:     0x7f9fe6d8c072 - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_data_structures[32839d0f870d4629]::vec_cache::VecCache<rustc_hir_id[d1ce817282485795]::OwnerId, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 8usize]>, rustc_query_system[cd9df96c377c45f]::dep_graph::graph::DepNodeIndex>, false, false, false>, false>
  41:     0x7f9fe6d88349 - rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace
  42:     0x7f9fe6f45eb4 - rustc_mir_transform[4dbfb044d0754d44]::mir_for_ctfe
  43:     0x7f9fe6f45667 - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_for_ctfe::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 8usize]>>
  44:     0x7f9fe6c10ba0 - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_query_system[cd9df96c377c45f]::query::caches::DefIdCache<rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 8usize]>>, false, false, false>, false>
  45:     0x7f9fe7c8db1b - rustc_query_impl[b221b5ddbbd9204d]::query_impl::mir_for_ctfe::get_query_non_incr::__rust_end_short_backtrace
  46:     0x7f9fe7c8d538 - <rustc_const_eval[d2ba75e3b2a83d67]::interpret::eval_context::InterpCx<rustc_const_eval[d2ba75e3b2a83d67]::const_eval::machine::CompileTimeMachine>>::load_mir
  47:     0x7f9fe7c8f4dd - rustc_const_eval[d2ba75e3b2a83d67]::const_eval::eval_queries::eval_to_allocation_raw_provider
  48:     0x7f9fe7c8ed80 - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::eval_to_allocation_raw::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 24usize]>>
  49:     0x7f9fe7c8e051 - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_query_system[cd9df96c377c45f]::query::caches::DefaultCache<rustc_middle[984b58fac644d3ae]::ty::PseudoCanonicalInput<rustc_middle[984b58fac644d3ae]::mir::interpret::GlobalId>, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 24usize]>>, false, false, false>, false>
  50:     0x7f9fe7c8dbf3 - rustc_query_impl[b221b5ddbbd9204d]::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
  51:     0x7f9fe7c88f8b - rustc_const_eval[d2ba75e3b2a83d67]::const_eval::eval_queries::eval_to_const_value_raw_provider
  52:     0x7f9fe7c88b0c - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::eval_to_const_value_raw::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 24usize]>>
  53:     0x7f9fe7c876ba - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_query_system[cd9df96c377c45f]::query::caches::DefaultCache<rustc_middle[984b58fac644d3ae]::ty::PseudoCanonicalInput<rustc_middle[984b58fac644d3ae]::mir::interpret::GlobalId>, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 24usize]>>, false, true, false>, false>
  54:     0x7f9fe7c8723d - rustc_query_impl[b221b5ddbbd9204d]::query_impl::eval_to_const_value_raw::get_query_non_incr::__rust_end_short_backtrace
  55:     0x7f9fe787bcb7 - <rustc_middle[984b58fac644d3ae]::ty::context::TyCtxt>::par_hir_body_owners::<rustc_hir_analysis[ea50d391a1a1477e]::check_crate::{closure#2}>::{closure#0}
  56:     0x7f9fe787b244 - rustc_hir_analysis[ea50d391a1a1477e]::check_crate
  57:     0x7f9fe6d848db - rustc_interface[92bda50b0b5d2d38]::passes::analysis
  58:     0x7f9fe6d84535 - rustc_query_impl[b221b5ddbbd9204d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b221b5ddbbd9204d]::query_impl::analysis::make_query_vtable::{closure#1}::{closure#0}, rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 0usize]>>
  59:     0x7f9fe7dcdee6 - rustc_query_system[cd9df96c377c45f]::query::plumbing::try_execute_query::<rustc_query_impl[b221b5ddbbd9204d]::SemiDynamicQueryDispatcher<rustc_query_system[cd9df96c377c45f]::query::caches::SingleCache<rustc_middle[984b58fac644d3ae]::query::erase::ErasedData<[u8; 0usize]>>, false, false, false>, false>
  60:     0x7f9fe7dcdcce - rustc_query_impl[b221b5ddbbd9204d]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  61:     0x7f9fe7f40caf - <rustc_interface[92bda50b0b5d2d38]::passes::create_and_enter_global_ctxt<core[60f2ed223aee2384]::option::Option<rustc_interface[92bda50b0b5d2d38]::queries::Linker>, rustc_driver_impl[bc96bfd14d55c39f]::run_compiler::{closure#0}::{closure#2}>::{closure#2} as core[60f2ed223aee2384]::ops::function::FnOnce<(&rustc_session[e7ff2c8762129473]::session::Session, rustc_middle[984b58fac644d3ae]::ty::context::CurrentGcx, alloc[a68f8e530fb470c9]::sync::Arc<rustc_data_structures[32839d0f870d4629]::jobserver::Proxy>, &std[a1fadf1b190cf199]::sync::once_lock::OnceLock<rustc_middle[984b58fac644d3ae]::ty::context::GlobalCtxt>, &rustc_data_structures[32839d0f870d4629]::sync::worker_local::WorkerLocal<rustc_middle[984b58fac644d3ae]::arena::Arena>, &rustc_data_structures[32839d0f870d4629]::sync::worker_local::WorkerLocal<rustc_hir[e9cc84718e7756fe]::Arena>, rustc_driver_impl[bc96bfd14d55c39f]::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
  62:     0x7f9fe7d7f9c8 - rustc_interface[92bda50b0b5d2d38]::interface::run_compiler::<(), rustc_driver_impl[bc96bfd14d55c39f]::run_compiler::{closure#0}>::{closure#1}
  63:     0x7f9fe7db8ffe - std[a1fadf1b190cf199]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[92bda50b0b5d2d38]::util::run_in_thread_with_globals<rustc_interface[92bda50b0b5d2d38]::util::run_in_thread_pool_with_globals<rustc_interface[92bda50b0b5d2d38]::interface::run_compiler<(), rustc_driver_impl[bc96bfd14d55c39f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  64:     0x7f9fe7db9520 - <std[a1fadf1b190cf199]::thread::lifecycle::spawn_unchecked<rustc_interface[92bda50b0b5d2d38]::util::run_in_thread_with_globals<rustc_interface[92bda50b0b5d2d38]::util::run_in_thread_pool_with_globals<rustc_interface[92bda50b0b5d2d38]::interface::run_compiler<(), rustc_driver_impl[bc96bfd14d55c39f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[60f2ed223aee2384]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  65:     0x7f9fe7dba3ac - <std[a1fadf1b190cf199]::sys::thread::unix::Thread>::new::thread_start
  66:     0x7f9fe169698b - <unknown>
  67:     0x7f9fe171a9cc - <unknown>
  68:                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: please make sure that you have updated to the latest nightly

note: rustc 1.95.0-nightly (1e9be1b77 2026-01-31) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z next-solver=globally -Z dump-mir-dir=dir

query stack during panic:
#0 [mir_const_qualif] const checking `_`
#1 [mir_promoted] promoting constants in MIR for `_`
#2 [mir_borrowck] borrow-checking `_`
#3 [mir_drops_elaborated_and_const_checked] elaborating drops for `_`
#4 [mir_for_ctfe] caching mir of `_` for CTFE
#5 [eval_to_allocation_raw] const-evaluating + checking `_`
#6 [eval_to_const_value_raw] simplifying constant for the type system `_`
#7 [analysis] running analysis passes on crate `mvce`
end of query stack
error: aborting due to 2 previous errors

Some errors have detailed explanations: E0601, E0658.
For more information about an error, try `rustc --explain E0601`.