ICE: coherence: `did not expect selection error when collecting ambiguity errors` #124845

matthiaskrgr · 2024-05-07T15:35:32Z

Code

trait Trait {
    type Assoc;
}

struct W<T: Trait<Assoc = u32>>(*mut T);
impl<T: ?Sized> Trait for W<W<W<T>>>
where
    W<T>: Trait,
{
    type Assoc = ();
}

trait NoOverlap {}
impl<T: Trait<W<T>>> NoOverlap for T {}


impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}

fn main() {}

Error output

` rustc ice.rs -Znext-solver=coherence

error[E0275]: overflow evaluating the requirement `W<W<W<_>>>: Trait`
  |
  = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`ice`)
note: required for `W<W<W<W<W<_>>>>>` to implement `Trait`
 --> ice.rs:6:17
  |
6 | impl<T: ?Sized> Trait for W<W<W<T>>>
  |                 ^^^^^     ^^^^^^^^^^
7 | where
8 |     W<T>: Trait,
  |           ----- unsatisfied trait bound introduced here
  = note: 126 redundant requirements hidden
  = note: required for `W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<W<...>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` to implement `Trait`
  = note: the full name for the type has been written to 'ice.long-type-16872895002395984658.txt'
  = note: consider using `--verbose` to print the full type name to the console

error[E0107]: trait takes 0 generic arguments but 1 generic argument was supplied
  --> ice.rs:14:9
   |
14 | impl<T: Trait<W<T>>> NoOverlap for T {}
   |         ^^^^^ expected 0 generic arguments
   |
note: trait defined here, with 0 generic parameters
  --> ice.rs:1:7
   |
1  | trait Trait {
   |       ^^^^^
help: replace the generic bound with the associated type
   |
14 | impl<T: Trait<Assoc = W<T>>> NoOverlap for T {}
   |               +++++++

Backtrace

error: internal compiler error: compiler/rustc_trait_selection/src/solve/fulfill.rs:264:17: did not expect selection error when collecting ambiguity errors

thread 'rustc' panicked at compiler/rustc_trait_selection/src/solve/fulfill.rs:264:17:
Box<dyn Any>
stack backtrace:
   0:     0x7a8d62606b35 - std::backtrace_rs::backtrace::libunwind::trace::h918aaf6e60cc0a20
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7a8d62606b35 - std::backtrace_rs::backtrace::trace_unsynchronized::h2eac6c94b93f8e3c
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7a8d62606b35 - std::sys_common::backtrace::_print_fmt::h8e5edaeb6a4352e8
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7a8d62606b35 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hf5cc6736d08af678
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7a8d62655cfb - core::fmt::rt::Argument::fmt::hb75c12041eb78bdc
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/core/src/fmt/rt.rs:165:63
   5:     0x7a8d62655cfb - core::fmt::write::h3e6a6276a812b52d
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/core/src/fmt/mod.rs:1157:21
   6:     0x7a8d625fb87f - std::io::Write::write_fmt::h1eb4d2f52c7badcc
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/io/mod.rs:1835:15
   7:     0x7a8d6260690e - std::sys_common::backtrace::_print::h027a355b4099d109
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7a8d6260690e - std::sys_common::backtrace::print::h9288434216016cb8
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7a8d62609279 - std::panicking::default_hook::{{closure}}::hb774f76bb0cbe3f3
  10:     0x7a8d62608fbd - std::panicking::default_hook::h5e6bb2fe4f610e68
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/panicking.rs:298:9
  11:     0x7a8d5eeb3d1f - std[2409bda48c37ea6b]::panicking::update_hook::<alloc[e4f27f1b259856c9]::boxed::Box<rustc_driver_impl[3b65384176704029]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7a8d62609976 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h150247b09595b272
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/alloc/src/boxed.rs:2036:9
  13:     0x7a8d62609976 - std::panicking::rust_panic_with_hook::h193842b19bca8c30
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/panicking.rs:799:13
  14:     0x7a8d5eee3cd4 - std[2409bda48c37ea6b]::panicking::begin_panic::<rustc_errors[cb4eda40c63952d6]::ExplicitBug>::{closure#0}
  15:     0x7a8d5eee0686 - std[2409bda48c37ea6b]::sys_common::backtrace::__rust_end_short_backtrace::<std[2409bda48c37ea6b]::panicking::begin_panic<rustc_errors[cb4eda40c63952d6]::ExplicitBug>::{closure#0}, !>
  16:     0x7a8d5eedbc66 - std[2409bda48c37ea6b]::panicking::begin_panic::<rustc_errors[cb4eda40c63952d6]::ExplicitBug>
  17:     0x7a8d5eeece61 - <rustc_errors[cb4eda40c63952d6]::diagnostic::BugAbort as rustc_errors[cb4eda40c63952d6]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7a8d5f3a04fc - rustc_middle[d85377d387f08e9a]::util::bug::opt_span_bug_fmt::<rustc_span[86ddde2698e45e98]::span_encoding::Span>::{closure#0}
  19:     0x7a8d5f384eca - rustc_middle[d85377d387f08e9a]::ty::context::tls::with_opt::<rustc_middle[d85377d387f08e9a]::util::bug::opt_span_bug_fmt<rustc_span[86ddde2698e45e98]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  20:     0x7a8d5f384d4b - rustc_middle[d85377d387f08e9a]::ty::context::tls::with_context_opt::<rustc_middle[d85377d387f08e9a]::ty::context::tls::with_opt<rustc_middle[d85377d387f08e9a]::util::bug::opt_span_bug_fmt<rustc_span[86ddde2698e45e98]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  21:     0x7a8d5d09cdd0 - rustc_middle[d85377d387f08e9a]::util::bug::bug_fmt
  22:     0x7a8d5f9d8dd7 - <rustc_trait_selection[e301c94095ae1ef9]::solve::fulfill::FulfillmentCtxt as rustc_infer[8f29aeb09f313402]::traits::engine::TraitEngine>::collect_remaining_errors
  23:     0x7a8d60575ba8 - <rustc_trait_selection[e301c94095ae1ef9]::traits::engine::ObligationCtxt>::select_all_or_error
  24:     0x7a8d607198de - rustc_trait_selection[e301c94095ae1ef9]::traits::coherence::overlap
  25:     0x7a8d60e75591 - <rustc_middle[d85377d387f08e9a]::traits::specialization_graph::Children as rustc_trait_selection[e301c94095ae1ef9]::traits::specialize::specialization_graph::ChildrenExt>::insert
  26:     0x7a8d5dedfa68 - <rustc_middle[d85377d387f08e9a]::traits::specialization_graph::Graph as rustc_trait_selection[e301c94095ae1ef9]::traits::specialize::specialization_graph::GraphExt>::insert
  27:     0x7a8d602866bc - rustc_trait_selection[e301c94095ae1ef9]::traits::specialize::specialization_graph_provider
  28:     0x7a8d6028621f - rustc_query_impl[f7d6eb8805e88c29]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f7d6eb8805e88c29]::query_impl::specialization_graph_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 8usize]>>
  29:     0x7a8d60288c17 - rustc_query_system[bd604859ea317a95]::query::plumbing::try_execute_query::<rustc_query_impl[f7d6eb8805e88c29]::DynamicConfig<rustc_query_system[bd604859ea317a95]::query::caches::DefIdCache<rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[f7d6eb8805e88c29]::plumbing::QueryCtxt, false>
  30:     0x7a8d608f2a32 - rustc_query_impl[f7d6eb8805e88c29]::query_impl::specialization_graph_of::get_query_non_incr::__rust_end_short_backtrace
  31:     0x7a8d60d62cb0 - rustc_hir_analysis[c4ab2add954ac9f7]::coherence::coherent_trait
  32:     0x7a8d60d629a3 - rustc_query_impl[f7d6eb8805e88c29]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f7d6eb8805e88c29]::query_impl::coherent_trait::dynamic_query::{closure#2}::{closure#0}, rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>
  33:     0x7a8d606bb793 - rustc_query_system[bd604859ea317a95]::query::plumbing::try_execute_query::<rustc_query_impl[f7d6eb8805e88c29]::DynamicConfig<rustc_query_system[bd604859ea317a95]::query::caches::DefIdCache<rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[f7d6eb8805e88c29]::plumbing::QueryCtxt, false>
  34:     0x7a8d606b9e89 - rustc_query_impl[f7d6eb8805e88c29]::query_impl::coherent_trait::get_query_non_incr::__rust_end_short_backtrace
  35:     0x7a8d608155ca - rustc_hir_analysis[c4ab2add954ac9f7]::check::wfcheck::check_well_formed
  36:     0x7a8d608133ad - rustc_query_impl[f7d6eb8805e88c29]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f7d6eb8805e88c29]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>
  37:     0x7a8d60812b40 - rustc_query_system[bd604859ea317a95]::query::plumbing::try_execute_query::<rustc_query_impl[f7d6eb8805e88c29]::DynamicConfig<rustc_query_system[bd604859ea317a95]::query::caches::VecCache<rustc_hir[606efbe1a170016d]::hir_id::OwnerId, rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[f7d6eb8805e88c29]::plumbing::QueryCtxt, false>
  38:     0x7a8d608128bf - rustc_query_impl[f7d6eb8805e88c29]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  39:     0x7a8d60810801 - rustc_hir_analysis[c4ab2add954ac9f7]::check::wfcheck::check_mod_type_wf
  40:     0x7a8d60810647 - rustc_query_impl[f7d6eb8805e88c29]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f7d6eb8805e88c29]::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>
  41:     0x7a8d60fb48c6 - rustc_query_system[bd604859ea317a95]::query::plumbing::try_execute_query::<rustc_query_impl[f7d6eb8805e88c29]::DynamicConfig<rustc_query_system[bd604859ea317a95]::query::caches::DefaultCache<rustc_span[86ddde2698e45e98]::def_id::LocalModDefId, rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[f7d6eb8805e88c29]::plumbing::QueryCtxt, false>
  42:     0x7a8d60fb467f - rustc_query_impl[f7d6eb8805e88c29]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
  43:     0x7a8d6052219e - rustc_hir_analysis[c4ab2add954ac9f7]::check_crate
  44:     0x7a8d60518c47 - rustc_interface[45e847dd6c11ec07]::passes::analysis
  45:     0x7a8d60518787 - rustc_query_impl[f7d6eb8805e88c29]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f7d6eb8805e88c29]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>
  46:     0x7a8d60faf165 - rustc_query_system[bd604859ea317a95]::query::plumbing::try_execute_query::<rustc_query_impl[f7d6eb8805e88c29]::DynamicConfig<rustc_query_system[bd604859ea317a95]::query::caches::SingleCache<rustc_middle[d85377d387f08e9a]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[f7d6eb8805e88c29]::plumbing::QueryCtxt, false>
  47:     0x7a8d60faeec9 - rustc_query_impl[f7d6eb8805e88c29]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  48:     0x7a8d60e270ce - rustc_interface[45e847dd6c11ec07]::interface::run_compiler::<core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>, rustc_driver_impl[3b65384176704029]::run_compiler::{closure#0}>::{closure#1}
  49:     0x7a8d60e126c9 - std[2409bda48c37ea6b]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[45e847dd6c11ec07]::util::run_in_thread_with_globals<rustc_interface[45e847dd6c11ec07]::util::run_in_thread_pool_with_globals<rustc_interface[45e847dd6c11ec07]::interface::run_compiler<core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>, rustc_driver_impl[3b65384176704029]::run_compiler::{closure#0}>::{closure#1}, core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>>::{closure#0}, core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>>
  50:     0x7a8d60e12478 - <<std[2409bda48c37ea6b]::thread::Builder>::spawn_unchecked_<rustc_interface[45e847dd6c11ec07]::util::run_in_thread_with_globals<rustc_interface[45e847dd6c11ec07]::util::run_in_thread_pool_with_globals<rustc_interface[45e847dd6c11ec07]::interface::run_compiler<core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>, rustc_driver_impl[3b65384176704029]::run_compiler::{closure#0}>::{closure#1}, core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>>::{closure#0}, core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e58631ecc326099b]::result::Result<(), rustc_span[86ddde2698e45e98]::ErrorGuaranteed>>::{closure#2} as core[e58631ecc326099b]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  51:     0x7a8d626137bb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h02edc3183d1b3ab4
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/alloc/src/boxed.rs:2022:9
  52:     0x7a8d626137bb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hd14ff6036f87e3a7
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/alloc/src/boxed.rs:2022:9
  53:     0x7a8d626137bb - std::sys::pal::unix::thread::Thread::new::thread_start::he158ab2f3983310c
                               at /rustc/7d83a4c131ab9ae81a74c6fd825c827d74a2881d/library/std/src/sys/pal/unix/thread.rs:108:17
  54:     0x7a8d623b255a - <unknown>
  55:     0x7a8d6242fa3c - <unknown>
  56:                0x0 - <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: please attach the file at `/tmp/im/rustc-ice-2024-05-07T15_33_11-55686.txt` to your bug report

note: compiler flags: -Z next-solver=coherence

query stack during panic:
#0 [specialization_graph_of] building specialization graph of trait `NoOverlap`
#1 [coherent_trait] coherence checking all impls of trait `NoOverlap`
#2 [check_well_formed] checking that `<impl at ice.rs:14:1: 14:37>` is well-formed
#3 [check_mod_type_wf] checking that types are well-formed in top-level module
#4 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 3 previous errors

Some errors have detailed explanations: E0107, E0275.
For more information about an error, try `rustc --explain E0107`.

The text was updated successfully, but these errors were encountered:

matthiaskrgr · 2024-05-07T18:56:57Z

bisects to #124418

Rollup merge of rust-lang#124871 - compiler-errors:overflowo, r=lcnr Don't ICE because recomputing overflow goals during find_best_leaf_obligation causes inference side-effects See the comments for more info. Reprocessing overflowed obligations may cause *other* goals to go from ambig -> pass/fail, causing an ICE. This suppresses that error, but makes all the overflow obligations messages back to their root obl. That kinda sucks, but 🤷 Fixes rust-lang#124834 Fixes rust-lang#124845 r? lcnr

rustbot added the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label May 7, 2024

compiler-errors self-assigned this May 7, 2024

compiler-errors mentioned this issue May 8, 2024

Don't ICE because recomputing overflow goals during find_best_leaf_obligation causes inference side-effects #124871

Merged

saethlin removed needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. E-needs-mcve Call for participation: This issue has a repro, but needs a Minimal Complete and Verifiable Example labels May 10, 2024

bors closed this as completed in 71ae7db May 16, 2024

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ICE: coherence: `did not expect selection error when collecting ambiguity errors` #124845

ICE: coherence: `did not expect selection error when collecting ambiguity errors` #124845

matthiaskrgr commented May 7, 2024

matthiaskrgr commented May 7, 2024

ICE: coherence: did not expect selection error when collecting ambiguity errors #124845

ICE: coherence: did not expect selection error when collecting ambiguity errors #124845

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matthiaskrgr commented May 7, 2024

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matthiaskrgr commented May 7, 2024

ICE: coherence: `did not expect selection error when collecting ambiguity errors` #124845

ICE: coherence: `did not expect selection error when collecting ambiguity errors` #124845