[ICE]: error performing operation: fully_perform

Code

I am compiling a FunDSP adaptor.

use fundsp::audionode::AudioNode;
use fundsp::audiounit::AudioUnit;
use fundsp::net::Net;
use fundsp::typenum::{Const, ToUInt, U, U2};
use fundsp::{Frame, Size};
use std::sync::Arc;

type GenericStereoToN<const N: usize> = Arc<dyn Fn([f32; N]) -> Net + Send + Sync>;

#[derive(Clone)]
pub struct StereoStaticParamsWrapper<const N: usize> {
    inner: GenericStereoToN<N>,
    effect: Net,
    params_state: [f32; N],
    params_temp: [f32; N],
}

impl<const N: usize> StereoStaticParamsWrapper<N> {
    fn new(inner: GenericStereoToN<N>) -> Self {
        StereoStaticParamsWrapper {
            inner,
            params_temp: [0.0; N],
            params_state: [0.0; N],
            effect: Net::new(2, 2),
        }
    }
}
impl<const N: usize> StereoStaticParamsWrapper<N>
where
    Const<N>: ToUInt,
    U<N>: Size<f32>,
{
    fn process_cc_events(&mut self, input: &Frame<f32, U<N>>) {
        // By convention 0, 1 slots will be stereo audio
        for i in 2..N {
            self.params_temp[i] = input[i];
        }
        if self.params_temp != self.params_state {
            self.effect = (self.inner)(self.params_temp);
            self.params_state = self.params_temp;
        };
    }
}

impl<const N: usize> AudioNode for StereoStaticParamsWrapper<N>
where
    Const<N>: ToUInt,
    U<N>: Size<f32>,
{
    const ID: u64 = 60000;
    type Inputs = U<N>;
    type Outputs = U2;
    fn reset(&mut self) {
        self.effect.reset();
    }

    fn set_sample_rate(&mut self, sample_rate: f64) {
        self.effect.set_sample_rate(sample_rate);
    }

    fn tick(&mut self, input: &Frame<f32, U<N>>) -> Frame<f32, Self::Outputs> {
        let mut output = [0.0f32; 2];
        self.process_cc_events(input);
        // By convention 0, 1 slots will be stereo audio
        self.effect.tick(&input[0..2], &mut output);
        Frame::from(output).into()
    }
}

Meta

rustc --version --verbose:

rustc 1.94.1 (e408947bf 2026-03-25)
binary: rustc
commit-hash: e408947bfd200af42db322daf0fadfe7e26d3bd1
commit-date: 2026-03-25
host: aarch64-apple-darwin
release: 1.94.1
LLVM version: 21.1.8

Error output

error: internal compiler error: error performing operation: fully_perform
  --> src/common/adapters.rs:83:9
   |
83 |         Frame::from(output).into()
   |         ^^^^^^^^^^^
   |
note: delayed at /rustc-dev/e408947bfd200af42db322daf0fadfe7e26d3bd1/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs:95:25
         0: std::backtrace::Backtrace::create
         1: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         2: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
         3: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         4: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
         5: <rustc_borrowck::type_check::TypeChecker>::ascribe_user_type
         6: rustc_borrowck::type_check::type_check
         7: <rustc_borrowck::root_cx::BorrowCheckRootCtxt>::do_mir_borrowck
         8: rustc_borrowck::mir_borrowck
         9: 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]>>
        10: 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>
        11: rustc_query_impl::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
        12: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface::passes::run_required_analyses::{closure#1}::{closure#0}>::{closure#0}
        13: rustc_interface::passes::analysis
        14: 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]>>
        15: 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>
        16: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        17: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>
        18: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        19: 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}, ()>
        20: <std::thread::lifecycle::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}
        21: std::sys::thread::unix::Thread::new::thread_start
        22: __pthread_cond_wait
      
  --> src/common/adapters.rs:83:9
   |
83 |         Frame::from(output).into()
   |         ^^^^^^^^^^^

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 1.94.1 (e408947bf 2026-03-25) running on aarch64-apple-darwin

note: compiler flags: --crate-type lib -C opt-level=3 -C embed-bitcode=no -C strip=debuginfo

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

query stack during panic:
end of query stack
warning: `nabi_core` (lib) generated 31 warnings (run `cargo fix --lib -p nabi_core` to apply 9 suggestions)
error: could not compile `nabi_core` (lib); 31 warnings emitted

<backtrace>

Reproduce the ICE with the FunDSP example and cargo build, then inspect src/common/adapters.rs:83 and the delayed operation in rustc_trait_selection/src/traits/query/type_op/custom.rs:95. Done means the example no longer triggers an internal compiler error and the regression is covered by an appropriate compiler test.