[ICE]: attempted .def_id() on invalid res: Err #153389
Description
auto-reduced (treereduce-rust):
trait Trait{
fn bar();
}
impl Trait for () {
reuse missing::<> as bar;
}
original:
#![feature(fn_delegation)]
trait Trait{
fn bar();
}
impl Trait for () {
reuse missing::<> as bar;
}
fn main() {}Version information
rustc 1.96.0-nightly (d933cf483 2026-03-04)
binary: rustc
commit-hash: d933cf483edf1605142ac6899ff32536c0ad8b22
commit-date: 2026-03-04
host: x86_64-unknown-linux-gnu
release: 1.96.0-nightly
LLVM version: 22.1.0
Possibly related line of code:
rust/compiler/rustc_hir/src/def.rs
Lines 821 to 833 in d933cf4
Command:
/home/matthias/.rustup/toolchains/master/bin/rustc
Program output
error[E0425]: cannot find function `missing` in this scope
--> /tmp/icemaker_global_tempdir.TGV4D8uIv167/rustc_testrunner_tmpdir_reporting.czTJlkk5GKxF/mvce.rs:7:11
|
7 | reuse missing::<> as bar;
| ^^^^^^^ not found in this scope
error[E0658]: functions delegation is not yet fully implemented
--> /tmp/icemaker_global_tempdir.TGV4D8uIv167/rustc_testrunner_tmpdir_reporting.czTJlkk5GKxF/mvce.rs:7:5
|
7 | reuse missing::<> as bar;
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #118212 <https://github.com/rust-lang/rust/issues/118212> for more information
= help: add `#![feature(fn_delegation)]` to the crate attributes to enable
= note: this compiler was built on 2026-03-04; consider upgrading it if it is out of date
error[E0601]: `main` function not found in crate `mvce`
--> /tmp/icemaker_global_tempdir.TGV4D8uIv167/rustc_testrunner_tmpdir_reporting.czTJlkk5GKxF/mvce.rs:8:2
|
8 | }
| ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.TGV4D8uIv167/rustc_testrunner_tmpdir_reporting.czTJlkk5GKxF/mvce.rs`
thread 'rustc' (1102290) panicked at /rustc-dev/d933cf483edf1605142ac6899ff32536c0ad8b22/compiler/rustc_hir/src/def.rs:827:45:
attempted .def_id() on invalid res: Err
stack backtrace:
0: 0x7f3fc935ef7b - <<std[69d51b4813ba037]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[51d4adbef590f61]::fmt::Display>::fmt
1: 0x7f3fc9a229c8 - core[51d4adbef590f61]::fmt::write
2: 0x7f3fc9375f86 - <std[69d51b4813ba037]::sys::stdio::unix::Stderr as std[69d51b4813ba037]::io::Write>::write_fmt
3: 0x7f3fc9335058 - std[69d51b4813ba037]::panicking::default_hook::{closure#0}
4: 0x7f3fc93523e3 - std[69d51b4813ba037]::panicking::default_hook
5: 0x7f3fc833d71c - std[69d51b4813ba037]::panicking::update_hook::<alloc[18203fec9a0cd4ec]::boxed::Box<rustc_driver_impl[9032f3c5cdcc149c]::install_ice_hook::{closure#1}>>::{closure#0}
6: 0x7f3fc93526c2 - std[69d51b4813ba037]::panicking::panic_with_hook
7: 0x7f3fc9335118 - std[69d51b4813ba037]::panicking::panic_handler::{closure#0}
8: 0x7f3fc932be49 - std[69d51b4813ba037]::sys::backtrace::__rust_end_short_backtrace::<std[69d51b4813ba037]::panicking::panic_handler::{closure#0}, !>
9: 0x7f3fc9336b7d - __rustc[cb16bc19fc993bd7]::rust_begin_unwind
10: 0x7f3fc5f1895c - core[51d4adbef590f61]::panicking::panic_fmt
11: 0x7f3fc84d589b - rustc_hir_analysis[bceba1a8102fadd5]::delegation::get_delegation_user_specified_args
12: 0x7f3fc84d445f - rustc_hir_analysis[bceba1a8102fadd5]::delegation::inherit_sig_for_delegation_item
13: 0x7f3fc8deea92 - rustc_query_impl[540cdfee4f8a4756]::query_impl::inherit_sig_for_delegation_item::invoke_provider_fn::__rust_begin_short_backtrace
14: 0x7f3fca41488c - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_data_structures[889238d3fa4068cd]::vec_cache::VecCache<rustc_span[a0277d8dc90b615]::def_id::LocalDefId, rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 16usize]>, rustc_middle[7e63d2df2dd45427]::dep_graph::graph::DepNodeIndex>, false>
15: 0x7f3fc8deeafa - rustc_query_impl[540cdfee4f8a4756]::query_impl::inherit_sig_for_delegation_item::execute_query_non_incr::__rust_end_short_backtrace
16: 0x7f3fca0b5b39 - <dyn rustc_hir_analysis[bceba1a8102fadd5]::hir_ty_lowering::HirTyLowerer>::lower_ty
17: 0x7f3fca0caeaf - <dyn rustc_hir_analysis[bceba1a8102fadd5]::hir_ty_lowering::HirTyLowerer>::lower_fn_ty
18: 0x7f3fc9cf14bc - rustc_hir_analysis[bceba1a8102fadd5]::collect::fn_sig
19: 0x7f3fc9cf0c26 - rustc_query_impl[540cdfee4f8a4756]::query_impl::fn_sig::invoke_provider_fn::__rust_begin_short_backtrace
20: 0x7f3fc9cf5360 - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_middle[7e63d2df2dd45427]::query::caches::DefIdCache<rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 24usize]>>, false>
21: 0x7f3fc9cf4853 - rustc_query_impl[540cdfee4f8a4756]::query_impl::fn_sig::execute_query_non_incr::__rust_end_short_backtrace
22: 0x7f3fca41b66b - rustc_hir_analysis[bceba1a8102fadd5]::check::compare_impl_item::check_method_is_structurally_compatible
23: 0x7f3fca420ac7 - rustc_hir_analysis[bceba1a8102fadd5]::check::compare_impl_item::compare_impl_item
24: 0x7f3fca420669 - rustc_query_impl[540cdfee4f8a4756]::query_impl::compare_impl_item::invoke_provider_fn::__rust_begin_short_backtrace
25: 0x7f3fca0dd219 - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_data_structures[889238d3fa4068cd]::vec_cache::VecCache<rustc_span[a0277d8dc90b615]::def_id::LocalDefId, rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 1usize]>, rustc_middle[7e63d2df2dd45427]::dep_graph::graph::DepNodeIndex>, false>
26: 0x7f3fca0dcd0e - rustc_query_impl[540cdfee4f8a4756]::query_impl::compare_impl_item::execute_query_non_incr::__rust_end_short_backtrace
27: 0x7f3fca0e01c0 - rustc_hir_analysis[bceba1a8102fadd5]::check::check::check_item_type
28: 0x7f3fca0ddca6 - rustc_hir_analysis[bceba1a8102fadd5]::check::wfcheck::check_well_formed
29: 0x7f3fca0ddc87 - rustc_query_impl[540cdfee4f8a4756]::query_impl::check_well_formed::invoke_provider_fn::__rust_begin_short_backtrace
30: 0x7f3fca0dd219 - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_data_structures[889238d3fa4068cd]::vec_cache::VecCache<rustc_span[a0277d8dc90b615]::def_id::LocalDefId, rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 1usize]>, rustc_middle[7e63d2df2dd45427]::dep_graph::graph::DepNodeIndex>, false>
31: 0x7f3fca0dcf7b - rustc_query_impl[540cdfee4f8a4756]::query_impl::check_well_formed::execute_query_non_incr::__rust_end_short_backtrace
32: 0x7f3fca0d9e7d - rustc_hir_analysis[bceba1a8102fadd5]::check::wfcheck::check_type_wf
33: 0x7f3fca0d9d87 - rustc_query_impl[540cdfee4f8a4756]::query_impl::check_type_wf::invoke_provider_fn::__rust_begin_short_backtrace
34: 0x7f3fcac90057 - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_middle[7e63d2df2dd45427]::query::caches::SingleCache<rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 1usize]>>, false>
35: 0x7f3fcac8fe29 - rustc_query_impl[540cdfee4f8a4756]::query_impl::check_type_wf::execute_query_non_incr::__rust_end_short_backtrace
36: 0x7f3fca3cb455 - rustc_hir_analysis[bceba1a8102fadd5]::check_crate
37: 0x7f3fc9a65619 - rustc_interface[5b554394f8ce662a]::passes::analysis
38: 0x7f3fcac91c1c - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_middle[7e63d2df2dd45427]::query::caches::SingleCache<rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 0usize]>>, false>
39: 0x7f3fcac9197b - rustc_query_impl[540cdfee4f8a4756]::query_impl::analysis::execute_query_non_incr::__rust_end_short_backtrace
40: 0x7f3fcac329ed - rustc_interface[5b554394f8ce662a]::interface::run_compiler::<(), rustc_driver_impl[9032f3c5cdcc149c]::run_compiler::{closure#0}>::{closure#1}
41: 0x7f3fcac5c6fe - std[69d51b4813ba037]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[5b554394f8ce662a]::util::run_in_thread_with_globals<rustc_interface[5b554394f8ce662a]::util::run_in_thread_pool_with_globals<rustc_interface[5b554394f8ce662a]::interface::run_compiler<(), rustc_driver_impl[9032f3c5cdcc149c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
42: 0x7f3fcac5cd60 - <std[69d51b4813ba037]::thread::lifecycle::spawn_unchecked<rustc_interface[5b554394f8ce662a]::util::run_in_thread_with_globals<rustc_interface[5b554394f8ce662a]::util::run_in_thread_pool_with_globals<rustc_interface[5b554394f8ce662a]::interface::run_compiler<(), rustc_driver_impl[9032f3c5cdcc149c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[51d4adbef590f61]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
43: 0x7f3fcac5dbec - <std[69d51b4813ba037]::sys::thread::unix::Thread>::new::thread_start
44: 0x7f3fc46a598b - <unknown>
45: 0x7f3fc4729a0c - <unknown>
46: 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 1.96.0-nightly (d933cf483 2026-03-04) running on x86_64-unknown-linux-gnu
query stack during panic:
#0 [inherit_sig_for_delegation_item] inheriting delegation signature
#1 [fn_sig] computing function signature of `<impl at /tmp/icemaker_global_tempdir.TGV4D8uIv167/rustc_testrunner_tmpdir_reporting.czTJlkk5GKxF/mvce.rs:6:1: 6:18>::bar`
#2 [compare_impl_item] checking assoc item `<impl at /tmp/icemaker_global_tempdir.TGV4D8uIv167/rustc_testrunner_tmpdir_reporting.czTJlkk5GKxF/mvce.rs:6:1: 6:18>::bar` is compatible with trait definition
#3 [check_well_formed] checking that `<impl at /tmp/icemaker_global_tempdir.TGV4D8uIv167/rustc_testrunner_tmpdir_reporting.czTJlkk5GKxF/mvce.rs:6:1: 6:18>` is well-formed
#4 [check_type_wf] checking that types are well-formed
#5 [analysis] running analysis passes on crate `mvce`
end of query stack
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0425, E0601, E0658.
For more information about an error, try `rustc --explain E0425`.
@rustbot label +F-fn_delegation