rust-lang/rust

ICE `Res::Err` but no error emitted

Opened this issue · 0 comments

auto-reduced (treereduce-rust):

#![feature(associated_type_defaults)]
trait Trait {
    type Assoc2
        = ()
    where
        for<const C: usize> [(); C]: Copy;
}

fn main() {}

original:

//@ check-pass
//@ run-rustfix

#![allow(dead_code)]
#![allow(dead_code)]

trait Trait {
    // Not fine, suggests moving.
    type Assoc where u32: Copy = ();
    //~^ WARNING where clause not allowed here
    // Not fine, suggests moving `u32: Copy`
    type Assoc2 where u32: Copy = () where
    for<const C: usize> [(); C]: Copy,;
    //~^ WARNING where clause not allowed here
}

fn main() {}

Version information

rustc 1.93.0-nightly (c90bcb957 2025-11-06)
binary: rustc
commit-hash: c90bcb9571b7aab0d8beaa2ce8a998ffaf079d38
commit-date: 2025-11-06
host: x86_64-unknown-linux-gnu
release: 1.93.0-nightly
LLVM version: 21.1.3

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zcrate-attr=feature(associated_type_defaults)

Program output

warning: trait `Trait` is never used
 --> /tmp/icemaker_global_tempdir.zD8pQUt7PVI8/rustc_testrunner_tmpdir_reporting.eEBxYaiIhvO4/mvce.rs:1:7
  |
1 | trait Trait {
  |       ^^^^^
  |
  = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default

warning: 1 warning 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: `Res::Err` but no error emitted
 --> /tmp/icemaker_global_tempdir.zD8pQUt7PVI8/rustc_testrunner_tmpdir_reporting.eEBxYaiIhvO4/mvce.rs:5:34
  |
5 |         for<const C: usize> [(); C]: Copy;
  |                                  ^
  |
note: delayed at compiler/rustc_hir_typeck/src/expr.rs:801:32
         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_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, &str>
         4: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_path
         5: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         6: rustc_hir_typeck::typeck_with_inspect::{closure#0}
         7: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
         8: 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>
         9: rustc_query_impl::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
        10: rustc_mir_build::thir::pattern::check_match::check_match
        11: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_match::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        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; 1]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        13: rustc_query_impl::query_impl::check_match::get_query_non_incr::__rust_end_short_backtrace
        14: rustc_mir_build::builder::build_mir
        15: rustc_mir_transform::mir_built
        16: 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]>>
        17: 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>
        18: rustc_query_impl::query_impl::mir_built::get_query_non_incr::__rust_end_short_backtrace
        19: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::trivial_const::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 32]>>
        20: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 32]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        21: rustc_query_impl::query_impl::trivial_const::get_query_non_incr::__rust_end_short_backtrace
        22: rustc_const_eval::const_eval::eval_queries::eval_to_allocation_raw_provider
        23: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>>
        24: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        25: rustc_query_impl::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
        26: rustc_const_eval::const_eval::valtrees::eval_to_valtree
        27: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::eval_to_valtree::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 16]>>
        28: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 16]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        29: rustc_query_impl::query_impl::eval_to_valtree::get_query_non_incr::__rust_end_short_backtrace
        30: <rustc_middle::ty::context::TyCtxt>::const_eval_resolve_for_typeck
        31: rustc_trait_selection::traits::try_evaluate_const
        32: <rustc_trait_selection::traits::normalize_param_env_or_error::{closure#0}::ConstNormalizer as rustc_type_ir::fold::TypeFolder<rustc_middle::ty::context::TyCtxt>>::fold_const
        33: <rustc_middle::ty::Ty as rustc_type_ir::fold::TypeSuperFoldable<rustc_middle::ty::context::TyCtxt>>::super_fold_with::<rustc_trait_selection::traits::normalize_param_env_or_error::{closure#0}::ConstNormalizer>
        34: rustc_trait_selection::traits::normalize_param_env_or_error
        35: rustc_ty_utils::ty::param_env
        36: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::param_env::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        37: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        38: rustc_query_impl::query_impl::param_env::get_query_non_incr::__rust_end_short_backtrace
        39: rustc_hir_analysis::check::compare_impl_item::check_type_bounds
        40: rustc_hir_analysis::check::check::check_item_type
        41: rustc_hir_analysis::check::wfcheck::check_well_formed
        42: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        43: 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; 1]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        44: rustc_query_impl::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
        45: rustc_hir_analysis::check::wfcheck::check_type_wf
        46: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        47: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 1]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        48: rustc_query_impl::query_impl::check_type_wf::get_query_non_incr::__rust_end_short_backtrace
        49: rustc_hir_analysis::check_crate
        50: rustc_interface::passes::analysis
        51: 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]>>
        52: 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>
        53: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        54: <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} as core::ops::function::FnOnce<(&rustc_session::session::Session, rustc_middle::ty::context::CurrentGcx, alloc::sync::Arc<rustc_data_structures::jobserver::Proxy>, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
        55: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        56: 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}, ()>
        57: <<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}
        58: std::sys::thread::unix::Thread::new::thread_start
        59: <unknown>
        60: <unknown>
      
 --> /tmp/icemaker_global_tempdir.zD8pQUt7PVI8/rustc_testrunner_tmpdir_reporting.eEBxYaiIhvO4/mvce.rs:5:34
  |
5 |         for<const C: usize> [(); C]: Copy;
  |                                  ^

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 1.93.0-nightly (c90bcb957 2025-11-06) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z crate-attr=feature(associated_type_defaults) -Z dump-mir-dir=dir

query stack during panic:
end of query stack

@rustbot label +F-associated_type_defaults