error performing operation: fully_perform in ascribe_user_type

[VincentVanlaer]

The following code is a minimization from some code using nalgebra.

The ICE is gone if any of the following changes are made

• Allocator<U2> is added to the bounds of ice
• Allocator<D> is removed from the bounds of ice
• the associated type Buffer is not used on the From implementation
• -Znext-solver is used

Code

use core::marker::PhantomData;

struct LeftReflector<S> {
    _phantom: PhantomData<S>,
}

struct DefaultAllocator {}

trait Allocator<R> {
    type Buffer;
}

struct U2 {}

impl Allocator<U2> for DefaultAllocator {
    type Buffer = [u8; 2];
}

impl<R> From<R> for LeftReflector<<DefaultAllocator as Allocator<R>>::Buffer>
where
    DefaultAllocator: Allocator<R>,
{
    fn from(_: R) -> Self {
        todo!()
    }
}

fn ice<D>(a: U2)
where
    DefaultAllocator: Allocator<D>,
{
    // ICE
    let _ = LeftReflector::from(a);
}

// Uncomment the following two functions to get an error instead of an ICE

// fn error<D: Dim>(a: U2)
// where
//     DefaultAllocator: Allocator<D>,
// {
//     // Normal error, R of to_reflector is inferred as D instead of U2
//     let _ = to_reflector(a);
// }
//
// fn to_reflector<R: Dim>(_: R) -> LeftReflector<<DefaultAllocator as Allocator<R>>::Buffer>
// where
//     DefaultAllocator: Allocator<R>,
// {
//     todo!()
// }

// This has no issues

// fn all_fine<D: Dim>(a: U2) {
//     let _ = LeftReflector::from(a);
// }

Meta

rustc --version --verbose:

rustc 1.87.0-nightly (75530e9f7 2025-03-18)
binary: rustc
commit-hash: 75530e9f72a1990ed2305e16fd51d02f47048f12
commit-date: 2025-03-18
host: x86_64-unknown-linux-gnu
release: 1.87.0-nightly
LLVM version: 20.1.0

Error output

error: internal compiler error: error performing operation: fully_perform

Backtrace

note: delayed at /rustc/75530e9f72a1990ed2305e16fd51d02f47048f12/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs:87:25
         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, alloc::string::String>
         4: <rustc_borrowck::type_check::TypeChecker>::ascribe_user_type
         5: rustc_borrowck::type_check::type_check
         6: rustc_borrowck::nll::compute_regions
         7: rustc_borrowck::do_mir_borrowck
         8: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
         9: 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, true>
        10: rustc_query_impl::query_impl::mir_borrowck::get_query_incr::__rust_end_short_backtrace
        11: rustc_interface::passes::run_required_analyses
        12: rustc_interface::passes::analysis
        13: 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]>>
        14: 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, true>
        15: rustc_query_impl::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
        16: 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}
        17: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        18: 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}, ()>
        19: <<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}
        20: std::sys::pal::unix::thread::Thread::new::thread_start
        21: start_thread
        22: __GI___clone3

[moxian]

Triage: Bisection is seemingly unhelpful

Started ICEing on nightly-2022-03-09 but with different message ("broken MIR")

output of nightly-2022-03-09

error: internal compiler error: no errors encountered even though `delay_span_bug` issued

error: internal compiler error: Encountered error `Unimplemented` selecting `Binder(<LeftReflector<[u8; 2]> as std::convert::From<U2>>, [])` during codegen
  |
  = note: delayed at compiler\rustc_trait_selection\src\traits\codegen.rs:69:32

error: internal compiler error: broken MIR in DefId(0:20 ~ mycrate[6517]::ice) (CanonicalUserTypeAnnotation { user_ty: Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }, CanonicalVarInfo { kind: Ty(General(U0)) }], value: TypeOf(DefId(2:2923 ~ core[5822]::convert::From::from), UserSubsts { substs: [LeftReflector<^0>, ^1], user_self_ty: None }) }, span: src\lib.rs:33:13: 33:32 (#0), inferred_ty: fn(U2) -> LeftReflector<<DefaultAllocator as Allocator<U2>>::Buffer> {<LeftReflector<<DefaultAllocator as Allocator<U2>>::Buffer> as std::convert::From<U2>>::from} }): bad user type AscribeUserType(fn(U2) -> LeftReflector<[u8; 2]> {<LeftReflector<[u8; 2]> as std::convert::From<U2>>::from}, DefId(2:2923 ~ core[5822]::convert::From::from) UserSubsts { substs: [LeftReflector<_>, _], user_self_ty: None }, type_of=fn(T) -> Self {<Self as std::convert::From<T>>::from}): NoSolution
  |
  = note: delayed at compiler\rustc_borrowck\src\type_check\mod.rs:1120:25

PRs for nightly-2022-03-09

********************************************************************************
Regression in nightly-2022-03-09
********************************************************************************

converted 2022-03-08 to 03918badd33d255de806b4a9a8aa75b031ed0738
converted 2022-03-09 to 1eb72580d076935a3e590deb6e5813a5aef3eca4
get_commits_between returning commits, len: 7
*  commit[0] 2022-03-07: Auto merge of #94706 - matthiaskrgr:rollup-l5erynr, r=matthiaskrgr
*  commit[1] 2022-03-07: Auto merge of #94709 - martingms:link-to-chunked-opt-pr, r=nnethercote
*  commit[2] 2022-03-08: Auto merge of #90887 - jackh726:issue-90729, r=nikomatsakis
*  commit[3] 2022-03-08: Auto merge of #94716 - RalfJung:miri, r=RalfJung
*  commit[4] 2022-03-08: Auto merge of #94734 - matthiaskrgr:rollup-28shqhy, r=matthiaskrgr
*  commit[5] 2022-03-08: Auto merge of #92260 - jyn514:less-python-logic, r=Mark-Simulacrum
*  commit[6] 2022-03-08: Auto merge of #94702 - b-naber:static-refs-mir, r=lcnr

• probably Try to normalize associated types before processing obligations #90887

Different ICE starting nightly-2023-05-27 ("error performing ParamEnvAnd")

output of nightly-2023-05-27

   Compiling mycrate v0.1.0 (H:\work\my\trash\rust-mini\thing)
warning: function `ice` is never used
  --> src\lib.rs:28:4
   |
28 | fn ice<D>(a: U2)
   |    ^^^
   |
   = note: `#[warn(dead_code)]` on by default

error: internal compiler error: no errors encountered even though `delay_span_bug` issued

error: internal compiler error: error performing ParamEnvAnd { param_env: ParamEnv { caller_bounds: [Binder(TraitPredicate(<DefaultAllocator as Allocator<D>>, polarity:Positive), []), Binder(TraitPredicate(<D as std::marker::Sized>, polarity:Positive), [])], reveal: UserFacing, constness: NotConst }, value: AscribeUserType { mir_ty: fn(U2) -> LeftReflector<<DefaultAllocator as Allocator<U2>>::Buffer> {<LeftReflector<<DefaultAllocator as Allocator<U2>>::Buffer> as std::convert::From<U2>>::from}, user_ty: TypeOf(DefId(2:2515 ~ core[48c0]::convert::From::from), UserSubsts { substs: [LeftReflector<_>, _], user_self_ty: None }) } }
  --> src\lib.rs:33:13
   |
33 |     let _ = LeftReflector::from(a);
   |             ^^^^^^^^^^^^^^^^^^^
   |
   = note: delayed at /rustc/1a5f8bce74ee432f7cc3aa131bc3d6920e06de10\compiler\rustc_trait_selection\src\traits\query\type_op\mod.rs:139:32
              0: std::backtrace::Backtrace::disabled
              1: std::backtrace::Backtrace::force_capture
              2: <rustc_errors::HandlerInner>::emit_diagnostic
              3: <rustc_borrowck::session_diagnostics::VarNeedNotMut as rustc_errors::diagnostic::DecorateLint<()>>::decorate_lint
              4: <rustc_borrowck::universal_regions::UniversalRegionIndices>::insert_late_bound_region
              5: <rustc_borrowck::type_check::Locations>::span
              6: <rustc_middle::mir::syntax::Place as rustc_borrowck::place_ext::PlaceExt>::ignore_borrow
              7: <rustc_borrowck::universal_regions::UniversalRegionIndices>::insert_late_bound_region
              8: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_middle::thir::visit::Visitor>::visit_expr
              9: <rustc_mir_build::thir::pattern::check_match::MatchVisitor as rustc_middle::thir::visit::Visitor>::visit_expr
             10: rustc_query_impl::query_callbacks
             11: rustc_query_impl::query_callbacks
             12: rustc_query_impl::query_callbacks
             13: rustc_query_impl::query_callbacks
             14: once_cell::imp::initialize_or_wait
             15: rustc_interface::interface::parse_check_cfg
             16: rustc_interface::passes::analysis
             17: rustc_query_impl::profiling_support::alloc_self_profile_query_strings
             18: rustc_query_impl::profiling_support::alloc_self_profile_query_strings
             19: rustc_query_impl::profiling_support::alloc_self_profile_query_strings
             20: rustc_query_impl::profiling_support::alloc_self_profile_query_strings
             21: rustc_driver_impl::main
             22: rustc_driver_impl::args::arg_expand_all
             23: rustc_driver_impl::args::arg_expand_all
             24: rustc_driver_impl::args::arg_expand_all
             25: std::sys::windows::thread::Thread::new
             26: BaseThreadInitThunk
             27: RtlUserThreadStart


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: rustc 1.71.0-nightly (1a5f8bce7 2023-05-26) running on x86_64-pc-windows-msvc

note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack

PRs for nightly-2023-05-27

********************************************************************************
Regression in nightly-2023-05-27
********************************************************************************

converted 2023-05-26 to a2b1646c597329d0a25efa3889b66650f65de1de
converted 2023-05-27 to 1a5f8bce74ee432f7cc3aa131bc3d6920e06de10
get_commits_between returning commits, len: 7
*  commit[0] 2023-05-25: Auto merge of #86844 - bjorn3:global_alloc_improvements, r=pnkfelix
*  commit[1] 2023-05-25: Auto merge of #111960 - compiler-errors:rollup-onka2dl, r=compiler-errors
*  commit[2] 2023-05-26: Auto merge of #111858 - clubby789:fluent-alphabetical, r=jyn514,compiler-errors
*  commit[3] 2023-05-26: Auto merge of #111918 - compiler-errors:custom-type-ops-err, r=lcnr
*  commit[4] 2023-05-26: Auto merge of #111984 - matthiaskrgr:rollup-6u7ynyv, r=matthiaskrgr
*  commit[5] 2023-05-26: Auto merge of #111562 - clubby789:speedup-bootstrap-py, r=jyn514
*  commit[6] 2023-05-26: Auto merge of #103291 - ink-feather-org:typeid_no_struct_match, r=dtolnay

• nothing stands out to me

Current ICE wording (but with different stack trace) starting nightly-2024-04-10

output of nightly-2024-04-10

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: error performing operation: fully_perform
  --> src\lib.rs:33:13
   |
33 |     let _ = LeftReflector::from(a);
   |             ^^^^^^^^^^^^^^^^^^^
   |
note: delayed at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf\compiler\rustc_trait_selection\src\traits\query\type_op\custom.rs:85:25
         0: std::backtrace_rs::backtrace::dbghelp64::trace
                   at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library\std\src\..\..\backtrace\src\backtrace\dbghelp64.rs:99
         1: std::backtrace_rs::backtrace::trace_unsynchronized
                   at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66
         2: std::backtrace::Backtrace::create
                   at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library\std\src\backtrace.rs:331
         3: std::backtrace::Backtrace::capture
                   at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library\std\src\backtrace.rs:296
         4: <rustc_errors::DiagCtxt>::emit_future_breakage_report
         5: <rustc_errors::DiagCtxt>::emit_diagnostic
         6: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         7: <rustc_borrowck::MirBorrowckCtxt>::check_if_path_or_subpath_is_moved
         8: <rustc_borrowck::type_check::relate_tys::NllTypeRelating as rustc_middle::ty::relate::TypeRelation>::consts
         9: rustc_borrowck::dataflow::calculate_borrows_out_of_scope_at_location
        10: <rustc_borrowck::type_check::relate_tys::NllTypeRelating as rustc_middle::ty::relate::TypeRelation>::tys
        11: rustc_borrowck::mir_borrowck
        12: rustc_query_impl::plumbing::query_key_hash_verify_all
        13: rustc_traits::type_op::type_op_prove_predicate
        14: rustc_query_impl::plumbing::query_key_hash_verify_all
        15: <rustc_interface::passes::LintStoreExpandImpl as rustc_expand::base::LintStoreExpand>::pre_expansion_lint
        16: rustc_interface::passes::create_global_ctxt
        17: <dyn std::io::Write as nu_ansi_term::write::AnyWrite>::write_str
        18: rustc_traits::type_op::type_op_normalize_clause
        19: rustc_query_impl::query_system
        20: __ImageBase
        21: __ImageBase
        22: __ImageBase
        23: alloc::boxed::impl$48::call_once
                   at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library\alloc\src\boxed.rs:2018
        24: alloc::boxed::impl$48::call_once
                   at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library\alloc\src\boxed.rs:2018
        25: std::sys::pal::windows::thread::impl$0::new::thread_start
                   at /rustc/8b2459c1f21187f9792d99310171a15e64feb9cf/library\std\src\sys\pal\windows\thread.rs:53
        26: BaseThreadInitThunk
        27: RtlUserThreadStart
  --> src\lib.rs:33:13
   |
33 |     let _ = LeftReflector::from(a);
   |             ^^^^^^^^^^^^^^^^^^^

note: it seems that this compiler `1.79.0-nightly (8b2459c1f 2024-04-09)` is outdated, a newer nightly should have been released in the meantime
  |
  = note: please consider running `rustup update nightly` to update the nightly channel and check if this problem still persists
  = note: if the problem still persists, 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 attach the file at `H:\work\my\trash\rust-mini\thing\rustc-ice-2025-03-28T23_59_27-6580.txt` to your bug report

note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack

PRs for nightly-2024-04-10:

********************************************************************************
Regression in nightly-2024-04-10
********************************************************************************
converted 2024-04-09 to ab5bda1aa70f707014e2e691e43bc37a8819252a
converted 2024-04-10 to 8b2459c1f21187f9792d99310171a15e64feb9cf
*  commit[0] 2024-04-08: Auto merge of #123645 - matthiaskrgr:rollup-yd8d7f1, r=matthiaskrgr
*  commit[1] 2024-04-08: Auto merge of #122077 - oli-obk:eager_opaque_checks4, r=lcnr
*  commit[2] 2024-04-09: Auto merge of #122387 - DianQK:re-enable-early-otherwise-branch, r=cjgillot
*  commit[3] 2024-04-09: Auto merge of #123099 - oli-obk:span_tcx, r=petrochenkov
*  commit[4] 2024-04-09: Auto merge of #123663 - matthiaskrgr:rollup-1qnj9j3, r=matthiaskrgr
*  commit[5] 2024-04-09: Auto merge of #123272 - saethlin:reachable-mono-cleanup, r=cjgillot
*  commit[6] 2024-04-09: Auto merge of #123631 - oli-obk:fail_slow, r=jieyouxu
*  commit[7] 2024-04-09: Auto merge of #123676 - GuillaumeGomez:rollup-1hurixy, r=GuillaumeGomez
*  commit[8] 2024-04-09: Auto merge of #123485 - madsmtm:use-libc-copyfile, r=joboet
*  commit[9] 2024-04-09: Auto merge of #123683 - pietroalbini:pa-cve-2024-24576-nightly, r=pietroalbini

• nothing stands out to me either

@rustbot label: +T-types +A-type-system +A-associated-items -needs-triage

[moxian]

See also #136666 #130797 #124189 that all have the same error and very similar (but not identical) query stack