found node must be a function/thread 'rustc' panicked at 'Box<dyn Any>' when using nom parser

[Keating950]

Code

src/main.rs is the only file/module, and it looks like this:

use nom::{character::complete::one_of, combinator::map, IResult};

pub enum Sexpr<'a> {
    Ident(&'a str),
}

fn parse_unary_op(s: &str) -> IResult<&str, Sexpr> {
    map(one_of("+-"), Sexpr::Ident)(s)
}

fn main() {}

I'm using nom v7.1.1.

Cargo.lock

# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
version = 3

[[package]]
name = "memchr"
version = "2.5.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"

[[package]]
name = "minimal-lexical"
version = "0.2.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"

[[package]]
name = "nom"
version = "7.1.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a8903e5a29a317527874d0402f867152a3d21c908bb0b933e416c65e301d4c36"
dependencies = [
 "memchr",
 "minimal-lexical",
]

[[package]]
name = "oxide-lisp"
version = "0.1.0"
dependencies = [
 "nom",
]

Meta

rustc --version --verbose:

rustc 1.68.0-nightly (9c07efe84 2022-12-16)
binary: rustc
commit-hash: 9c07efe84f28a44f3044237696acc295aa407ee5
commit-date: 2022-12-16
host: x86_64-unknown-linux-gnu
release: 1.68.0-nightly
LLVM version: 15.0.6

Error output

error: internal compiler error: compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs:3479:28: found node must be a function
 --> src/main.rs:4:5
  |
4 |     Ident(&'a str),
  |     ^^^^^

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/9c07efe84f28a44f3044237696acc295aa407ee5/compiler/rustc_errors/src/lib.rs:973:33

Backtrace

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/9c07efe84f28a44f3044237696acc295aa407ee5/compiler/rustc_errors/src/lib.rs:973:33
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: std::panic::panic_any::<rustc_errors::ExplicitBug>
   2: <rustc_errors::HandlerInner>::span_bug::<rustc_span::span_encoding::Span, &alloc::string::String>
   3: <rustc_errors::Handler>::span_bug::<rustc_span::span_encoding::Span, &alloc::string::String>
   4: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, ()>::{closure#0}, ()>
   5: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: rustc_trait_selection::traits::error_reporting::suggestions::hint_missing_borrow
   8: <rustc_infer::infer::error_reporting::TypeErrCtxt as rustc_trait_selection::traits::error_reporting::suggestions::TypeErrCtxtExt>::report_closure_arg_mismatch
   9: <rustc_infer::infer::error_reporting::TypeErrCtxt as rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt>::report_selection_error
  10: <rustc_infer::infer::error_reporting::TypeErrCtxt as rustc_trait_selection::traits::error_reporting::InferCtxtPrivExt>::report_fulfillment_error
  11: <rustc_infer::infer::error_reporting::TypeErrCtxt as rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt>::report_fulfillment_errors
  12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_argument_types
  13: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_call
  14: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  15: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_call
  16: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  17: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_block_with_expected
  18: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  19: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_return_expr
  20: rustc_hir_typeck::check::check_fn
  21: <rustc_hir_typeck::inherited::InheritedBuilder>::enter::<rustc_hir_typeck::typeck_with_fallback<rustc_hir_typeck::typeck::{closure#0}>::{closure#0}::{closure#1}, &rustc_middle::ty::typeck_results::TypeckResults>
  22: rustc_hir_typeck::typeck
  23: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, rustc_span::def_id::LocalDefId, &rustc_middle::ty::typeck_results::TypeckResults>
  24: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::VecCache<rustc_span::def_id::LocalDefId, &rustc_middle::ty::typeck_results::TypeckResults>>
  25: rustc_data_structures::sync::par_for_each_in::<&[rustc_span::def_id::LocalDefId], <rustc_middle::hir::map::Map>::par_body_owners<rustc_hir_typeck::typeck_item_bodies::{closure#0}>::{closure#0}>
  26: rustc_hir_typeck::typeck_item_bodies
  27: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, (), ()>
  28: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), ()>>
  29: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::typeck_item_bodies, rustc_query_impl::plumbing::QueryCtxt>
  30: <rustc_session::session::Session>::time::<(), rustc_hir_analysis::check_crate::{closure#7}>
  31: rustc_hir_analysis::check_crate
  32: rustc_interface::passes::analysis
  33: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, (), core::result::Result<(), rustc_errors::ErrorGuaranteed>>
  34: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), core::result::Result<(), rustc_errors::ErrorGuaranteed>>>
  35: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::analysis, rustc_query_impl::plumbing::QueryCtxt>
  36: <rustc_interface::passes::QueryContext>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}::{closure#2}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
  37: <rustc_interface::interface::Compiler>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_errors::ErrorGuaranteed>>
  38: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  39: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

note: 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: rustc 1.68.0-nightly (9c07efe84 2022-12-16) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type bin -C embed-bitcode=no -C debuginfo=2 -C linker=/usr/bin/clang -C incremental=[REDACTED] -C link-arg=--ld-path=/usr/bin/mold

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

query stack during panic:
#0 [typeck] type-checking `parse_unary_op`
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `oxide-lisp`