ICE: `unexpected type in foreign function: {type error}'`

[matthiaskrgr]

auto-reduced (treereduce-rust):

use std::mem;

macro_rules! define_reify_functions {
    ($(
        fn $name:ident $(<$($param:ident),*>)?
            for $(extern $abi:tt)? fn($($arg:ident: $arg_ty:ty),*) -> $ret_ty:ty;
    )+) => {
        $(pub const fn $name<
            $($($param,)*)?
            F: Fn($($arg_ty),*) -> $ret_ty + Copy
        >(f: F) -> $(extern $abi)? fn($($arg_ty),*) -> $ret_ty {


            assert!(mem::size_of::<F>() == 0, );

            $(extern $abi)? fn wrapper<
                $($($param,)*)?
                F: Fn($($arg_ty),*) -> $ret_ty + Copy
            >($($arg: $arg_ty),*) -> $ret_ty {
                let f = unsafe {


                    mem::MaybeUninit::<F>::uninit().assume_init()
                };
                f($($arg),*)
            }
            let _f_proof = f;
            wrapper::<
                $($($param,)*)?
                F
            >
        })+
    }
}

define_reify_functions! {
    fn _reify_to_extern_c_fn_unary<A, R> for extern "C" fn(arg: A) -> R;
    fn reify_to_extern_c_fn_hrt_bridge<R> for extern "C" fn(bridge: super::BridgeConfig<'_>) -> R;
}

original code

original:

//! Abstraction for creating `fn` pointers from any callable that *effectively*
//! has the equivalent of implementing `Default`, even if the compiler neither
//! provides `Default` nor allows reifying closures (i.e. creating `fn` pointers)
//! other than those with absolutely no captures.
//!
//! More specifically, for a closure-like type to be "effectively `Default`":
//! * it must be a ZST (zero-sized type): no information contained within, so
//!   that `Default`'s return value (if it were implemented) is unambiguous
//! * it must be `Copy`: no captured "unique ZST tokens" or any other similar
//!   types that would make duplicating values at will unsound
//!   * combined with the ZST requirement, this confers a kind of "telecopy"
//!     ability: similar to `Copy`, but without keeping the value around, and
//!     instead "reconstructing" it (a noop given it's a ZST) when needed
//! * it must be *provably* inhabited: no captured uninhabited types or any
//!   other types that cannot be constructed by the user of this abstraction
//!   * the proof is a value of the closure-like type itself, in a sense the
//!     "seed" for the "telecopy" process made possible by ZST + `Copy`
//!   * this requirement is the only reason an abstraction limited to a specific
//!     usecase is required: ZST + `Copy` can be checked with *at worst* a panic
//!     at the "attempted `::default()` call" time, but that doesn't guarantee
//!     that the value can be soundly created, and attempting to use the typical
//!     "proof ZST token" approach leads yet again to having a ZST + `Copy` type
//!     that is not proof of anything without a value (i.e. isomorphic to a
//!     newtype of the type it's trying to prove the inhabitation of)
//!
//! A more flexible (and safer) solution to the general problem could exist once
//! `const`-generic parameters can have type parameters in their types:
//!
//! ```rust,ignore (needs future const-generics)
//! extern "C" fn ffi_wrapper<
//!     A, R,
//!     F: Fn(A) -> R,
//!     const f: F, // <-- this `const`-generic is not yet allowed
//! >(arg: A) -> R {
//!     f(arg)
//! }
//! ```

use std::mem;

// FIXME(eddyb) this could be `trait` impls except for the `const fn` requirement.
macro_rules! define_reify_functions {
    ($(
        fn $name:ident $(<$($param:ident),*>)?
            for $(extern $abi:tt)? fn($($arg:ident: $arg_ty:ty),*) -> $ret_ty:ty;
    )+) => {
        $(pub const fn $name<
            $($($param,)*)?
            F: Fn($($arg_ty),*) -> $ret_ty + Copy
        >(f: F) -> $(extern $abi)? fn($($arg_ty),*) -> $ret_ty {
            // FIXME(eddyb) describe the `F` type (e.g. via `type_name::<F>`) once panic
            // formatting becomes possible in `const fn`.
            assert!(mem::size_of::<F>() == 0, "selfless_reify: closure must be zero-sized");

            $(extern $abi)? fn wrapper<
                $($($param,)*)?
                F: Fn($($arg_ty),*) -> $ret_ty + Copy
            >($($arg: $arg_ty),*) -> $ret_ty {
                let f = unsafe {
                    // SAFETY: `F` satisfies all criteria for "out of thin air"
                    // reconstructability (see module-level doc comment).
                    mem::MaybeUninit::<F>::uninit().assume_init()
                };
                f($($arg),*)
            }
            let _f_proof = f;
            wrapper::<
                $($($param,)*)?
                F
            >
        })+
    }
}

define_reify_functions! {
    fn _reify_to_extern_c_fn_unary<A, R> for extern "C" fn(arg: A) -> R;

    // HACK(eddyb) this abstraction is used with `for<'a> fn(BridgeConfig<'a>)
    // -> T` but that doesn't work with just `reify_to_extern_c_fn_unary`
    // because of the `fn` pointer type being "higher-ranked" (i.e. the
    // `for<'a>` binder).
    // FIXME(eddyb) try to remove the lifetime from `BridgeConfig`, that'd help.
    fn reify_to_extern_c_fn_hrt_bridge<R> for extern "C" fn(bridge: super::BridgeConfig<'_>) -> R;
}

Version information

rustc 1.78.0-nightly (f70f19fef 2024-02-22)
binary: rustc
commit-hash: f70f19fef41cfdda75c92f163434c29ad046cf09
commit-date: 2024-02-22
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 18.1.0

Command:
/home/gh-matthiaskrgr/.rustup/toolchains/master/bin/rustc --crate-type=lib

Program output

error: internal compiler error: compiler/rustc_lint/src/types.rs:1439:32: unexpected type in foreign function: {type error}

thread 'rustc' panicked at compiler/rustc_middle/src/util/bug.rs:35:44:
Box<dyn Any>
stack backtrace:
   0:     0x7f9ec8d8caf6 - std::backtrace_rs::backtrace::libunwind::trace::hef019eae7250a090
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f9ec8d8caf6 - std::backtrace_rs::backtrace::trace_unsynchronized::h163c9c558e7f1e4e
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f9ec8d8caf6 - std::sys_common::backtrace::_print_fmt::h84a7f2dbeae8e017
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f9ec8d8caf6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hf7737af35c1403cd
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f9ec8ddda7c - core::fmt::rt::Argument::fmt::h027f33016919ab54
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/core/src/fmt/rt.rs:142:9
   5:     0x7f9ec8ddda7c - core::fmt::write::hed9b631feef55974
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/core/src/fmt/mod.rs:1120:17
   6:     0x7f9ec8d814bf - std::io::Write::write_fmt::h3b1c8483aebfcef8
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/io/mod.rs:1846:15
   7:     0x7f9ec8d8c8a4 - std::sys_common::backtrace::_print::h526b95c0b60f4650
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f9ec8d8c8a4 - std::sys_common::backtrace::print::h3322d8b0a1d6207a
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f9ec8d8f5eb - std::panicking::default_hook::{{closure}}::h9f07e6147b1c8a2e
  10:     0x7f9ec8d8f339 - std::panicking::default_hook::h395b386ace4fbcb6
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/panicking.rs:292:9
  11:     0x7f9ecbc7073c - std[d26ecb90c771e100]::panicking::update_hook::<alloc[100d4e65626f4394]::boxed::Box<rustc_driver_impl[ab901dc85bea4c82]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f9ec8d8fd50 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h1a188bbe7a6bf646
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/alloc/src/boxed.rs:2030:9
  13:     0x7f9ec8d8fd50 - std::panicking::rust_panic_with_hook::h1eec7c1097026ee4
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/panicking.rs:786:13
  14:     0x7f9ecbc9ce14 - std[d26ecb90c771e100]::panicking::begin_panic::<rustc_errors[e9339b16b54c0bc0]::ExplicitBug>::{closure#0}
  15:     0x7f9ecbc99d36 - std[d26ecb90c771e100]::sys_common::backtrace::__rust_end_short_backtrace::<std[d26ecb90c771e100]::panicking::begin_panic<rustc_errors[e9339b16b54c0bc0]::ExplicitBug>::{closure#0}, !>
  16:     0x7f9ecbc99a16 - std[d26ecb90c771e100]::panicking::begin_panic::<rustc_errors[e9339b16b54c0bc0]::ExplicitBug>
  17:     0x7f9eca618a41 - <rustc_errors[e9339b16b54c0bc0]::diagnostic::BugAbort as rustc_errors[e9339b16b54c0bc0]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7f9ecc07ae3c - <rustc_errors[e9339b16b54c0bc0]::DiagCtxt>::bug::<alloc[100d4e65626f4394]::string::String>
  19:     0x7f9ecc11faab - rustc_middle[771c523b66a87e77]::util::bug::opt_span_bug_fmt::<rustc_span[4d20b27f335b5d92]::span_encoding::Span>::{closure#0}
  20:     0x7f9ecc1033aa - rustc_middle[771c523b66a87e77]::ty::context::tls::with_opt::<rustc_middle[771c523b66a87e77]::util::bug::opt_span_bug_fmt<rustc_span[4d20b27f335b5d92]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7f9ecc103248 - rustc_middle[771c523b66a87e77]::ty::context::tls::with_context_opt::<rustc_middle[771c523b66a87e77]::ty::context::tls::with_opt<rustc_middle[771c523b66a87e77]::util::bug::opt_span_bug_fmt<rustc_span[4d20b27f335b5d92]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7f9eca590ee0 - rustc_middle[771c523b66a87e77]::util::bug::bug_fmt
  23:     0x7f9ece1cc3af - <rustc_lint[ee0ae86ad0d71ee5]::types::ImproperCTypesVisitor>::check_type_for_ffi.cold.0
  24:     0x7f9ecd1421ca - <rustc_lint[ee0ae86ad0d71ee5]::types::ImproperCTypesVisitor>::check_type_for_ffi
  25:     0x7f9ecd14161e - <rustc_lint[ee0ae86ad0d71ee5]::types::ImproperCTypesVisitor>::check_type_for_ffi_and_report_errors
  26:     0x7f9ecd75d352 - <rustc_lint[ee0ae86ad0d71ee5]::types::ImproperCTypesVisitor>::check_fn
  27:     0x7f9ecd75c0be - <rustc_lint[ee0ae86ad0d71ee5]::BuiltinCombinedModuleLateLintPass as rustc_lint[ee0ae86ad0d71ee5]::passes::LateLintPass>::check_fn
  28:     0x7f9ecd3a8cbe - <rustc_lint[ee0ae86ad0d71ee5]::late::LateContextAndPass<rustc_lint[ee0ae86ad0d71ee5]::BuiltinCombinedModuleLateLintPass> as rustc_hir[c73f1de04e7d2c16]::intravisit::Visitor>::visit_nested_item
  29:     0x7f9ecd3a70bf - rustc_lint[ee0ae86ad0d71ee5]::lint_mod
  30:     0x7f9ecd3a6eb9 - rustc_query_impl[9d2321c4f9b7ef6e]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[9d2321c4f9b7ef6e]::query_impl::lint_mod::dynamic_query::{closure#2}::{closure#0}, rustc_middle[771c523b66a87e77]::query::erase::Erased<[u8; 0usize]>>
  31:     0x7f9ecdba4cad - rustc_query_system[1927276894a91dd8]::query::plumbing::try_execute_query::<rustc_query_impl[9d2321c4f9b7ef6e]::DynamicConfig<rustc_query_system[1927276894a91dd8]::query::caches::DefaultCache<rustc_span[4d20b27f335b5d92]::def_id::LocalModDefId, rustc_middle[771c523b66a87e77]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9d2321c4f9b7ef6e]::plumbing::QueryCtxt, false>
  32:     0x7f9ecdba35bf - rustc_query_impl[9d2321c4f9b7ef6e]::query_impl::lint_mod::get_query_non_incr::__rust_end_short_backtrace
  33:     0x7f9ecdba315f - rustc_lint[ee0ae86ad0d71ee5]::late::check_crate::{closure#1}
  34:     0x7f9ecdba2b5e - rustc_lint[ee0ae86ad0d71ee5]::late::check_crate
  35:     0x7f9ecdb9ca65 - rustc_interface[863afa250f767019]::passes::analysis
  36:     0x7f9ecdb9b759 - rustc_query_impl[9d2321c4f9b7ef6e]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[9d2321c4f9b7ef6e]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[771c523b66a87e77]::query::erase::Erased<[u8; 1usize]>>
  37:     0x7f9ecdd45303 - rustc_query_system[1927276894a91dd8]::query::plumbing::try_execute_query::<rustc_query_impl[9d2321c4f9b7ef6e]::DynamicConfig<rustc_query_system[1927276894a91dd8]::query::caches::SingleCache<rustc_middle[771c523b66a87e77]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[9d2321c4f9b7ef6e]::plumbing::QueryCtxt, false>
  38:     0x7f9ecdd4507f - rustc_query_impl[9d2321c4f9b7ef6e]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  39:     0x7f9ecdd54556 - rustc_interface[863afa250f767019]::interface::run_compiler::<core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>, rustc_driver_impl[ab901dc85bea4c82]::run_compiler::{closure#0}>::{closure#0}
  40:     0x7f9ecdfbe305 - std[d26ecb90c771e100]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[863afa250f767019]::util::run_in_thread_with_globals<rustc_interface[863afa250f767019]::util::run_in_thread_pool_with_globals<rustc_interface[863afa250f767019]::interface::run_compiler<core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>, rustc_driver_impl[ab901dc85bea4c82]::run_compiler::{closure#0}>::{closure#0}, core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>>::{closure#0}, core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>>
  41:     0x7f9ecdfbe132 - <<std[d26ecb90c771e100]::thread::Builder>::spawn_unchecked_<rustc_interface[863afa250f767019]::util::run_in_thread_with_globals<rustc_interface[863afa250f767019]::util::run_in_thread_pool_with_globals<rustc_interface[863afa250f767019]::interface::run_compiler<core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>, rustc_driver_impl[ab901dc85bea4c82]::run_compiler::{closure#0}>::{closure#0}, core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>>::{closure#0}, core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[17d6b7ce805ba05e]::result::Result<(), rustc_span[4d20b27f335b5d92]::ErrorGuaranteed>>::{closure#1} as core[17d6b7ce805ba05e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  42:     0x7f9ec8d99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h1e27cc9781dd2875
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/alloc/src/boxed.rs:2016:9
  43:     0x7f9ec8d99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h4e0d9eddec111fd1
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/alloc/src/boxed.rs:2016:9
  44:     0x7f9ec8d99725 - std::sys::pal::unix::thread::Thread::new::thread_start::h8ca0c4b428df1792
                               at /rustc/f70f19fef41cfdda75c92f163434c29ad046cf09/library/std/src/sys/pal/unix/thread.rs:108:17
  45:     0x7f9ec8a94ac3 - start_thread
                               at ./nptl/pthread_create.c:442:8
  46:     0x7f9ec8b26850 - __GI___clone3
                               at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
  47:                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: rustc 1.78.0-nightly (f70f19fef 2024-02-22) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type lib -Z dump-mir-dir=dir

query stack during panic:
#0 [lint_mod] linting top-level module
#1 [analysis] running analysis passes on this crate
end of query stack
error[E0433]: failed to resolve: there are too many leading `super` keywords
  --> /tmp/icemaker_global_tempdir.lTYtezpoweDB/rustc_testrunner_tmpdir_reporting.5A2nqZBfiMNU/mvce.rs:53:69
   |
53 |     fn reify_to_extern_c_fn_hrt_bridge<R> for extern "C" fn(bridge: super::BridgeConfig<'_>) -> R;
   |                                                                     ^^^^^ there are too many leading `super` keywords

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0433`.

[matthiaskrgr]

smaller:

auto-reduced (treereduce-rust):

#![crate_type = "lib"]

pub extern "C" fn cb() -> libc::uintptr_t {}

original:

#![crate_name = "externcallback"]
#![crate_type = "lib"]
#![feature(rustc_private)]

extern crate libc;

pub mod rustrt {
    extern crate libc;

    #[link(name = "rust_test_helpers", kind = c"static")]
    extern "C" {
        pub fn rust_dbg_call(
            cb: extern "C" fn(libc::uintptr_t) -> libc::uintptr_t,
            data: libc::uintptr_t,
        ) -> Self::Routing;
    }
}

pub fn fact(n: libc::uintptr_t) -> libc::uintptr_t {
    unsafe {
        println!("n = {}", n);
        rustrt::rust_dbg_call(cb, n)
    }
}

pub extern "C" fn cb(data: libc::uintptr_t) -> libc::uintptr_t {
    if data == 1 { data } else { fact(data - 1) * data }
}

Version information

rustc 1.78.0-nightly (52cea084b 2024-02-23)
binary: rustc
commit-hash: 52cea084bd5bbac12ecfa5c0499f5c777025c968
commit-date: 2024-02-23
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 18.1.0

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc --edition=2021

Program output

error: internal compiler error: compiler/rustc_lint/src/types.rs:1439:32: unexpected type in foreign function: {type error}

thread 'rustc' panicked at compiler/rustc_middle/src/util/bug.rs:35:44:
Box<dyn Any>
stack backtrace:
   0:     0x7f1335d8caf6 - std::backtrace_rs::backtrace::libunwind::trace::he0282bd7aa79d0f5
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f1335d8caf6 - std::backtrace_rs::backtrace::trace_unsynchronized::hd257d30ae267ec37
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f1335d8caf6 - std::sys_common::backtrace::_print_fmt::h4d76d87d5818822c
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f1335d8caf6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hda8b13640513c0ca
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f1335ddda7c - core::fmt::rt::Argument::fmt::h0e78e7472c6726f6
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/core/src/fmt/rt.rs:142:9
   5:     0x7f1335ddda7c - core::fmt::write::h92726084111378c3
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/core/src/fmt/mod.rs:1120:17
   6:     0x7f1335d814bf - std::io::Write::write_fmt::hae4e2cfe04fc8ffe
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/io/mod.rs:1846:15
   7:     0x7f1335d8c8a4 - std::sys_common::backtrace::_print::ha088f411ecf7b854
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f1335d8c8a4 - std::sys_common::backtrace::print::h3cf71d8220ad62fb
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f1335d8f5eb - std::panicking::default_hook::{{closure}}::h40fbaa4ba62f2a25
  10:     0x7f1335d8f339 - std::panicking::default_hook::h4bae8cc7cdeafbdc
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/panicking.rs:292:9
  11:     0x7f1338c859dc - std[67003dfa8d3cf222]::panicking::update_hook::<alloc[39168ee3c7236603]::boxed::Box<rustc_driver_impl[7f540b76ed15adf]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f1335d8fd50 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h9766e5d4d8db67de
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/alloc/src/boxed.rs:2030:9
  13:     0x7f1335d8fd50 - std::panicking::rust_panic_with_hook::h8e53bf6707538e9c
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/panicking.rs:786:13
  14:     0x7f1338cb2084 - std[67003dfa8d3cf222]::panicking::begin_panic::<rustc_errors[69afeb585d680721]::ExplicitBug>::{closure#0}
  15:     0x7f1338caecd6 - std[67003dfa8d3cf222]::sys_common::backtrace::__rust_end_short_backtrace::<std[67003dfa8d3cf222]::panicking::begin_panic<rustc_errors[69afeb585d680721]::ExplicitBug>::{closure#0}, !>
  16:     0x7f1338caa496 - std[67003dfa8d3cf222]::panicking::begin_panic::<rustc_errors[69afeb585d680721]::ExplicitBug>
  17:     0x7f1338cbba71 - <rustc_errors[69afeb585d680721]::diagnostic::BugAbort as rustc_errors[69afeb585d680721]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7f1339092f4c - <rustc_errors[69afeb585d680721]::DiagCtxt>::bug::<alloc[39168ee3c7236603]::string::String>
  19:     0x7f1339137c9b - rustc_middle[71d5f388b7d1fdf2]::util::bug::opt_span_bug_fmt::<rustc_span[9f840697e39ebf3c]::span_encoding::Span>::{closure#0}
  20:     0x7f133911b4ea - rustc_middle[71d5f388b7d1fdf2]::ty::context::tls::with_opt::<rustc_middle[71d5f388b7d1fdf2]::util::bug::opt_span_bug_fmt<rustc_span[9f840697e39ebf3c]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7f133911b368 - rustc_middle[71d5f388b7d1fdf2]::ty::context::tls::with_context_opt::<rustc_middle[71d5f388b7d1fdf2]::ty::context::tls::with_opt<rustc_middle[71d5f388b7d1fdf2]::util::bug::opt_span_bug_fmt<rustc_span[9f840697e39ebf3c]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7f133757bb40 - rustc_middle[71d5f388b7d1fdf2]::util::bug::bug_fmt
  23:     0x7f133b27d827 - <rustc_lint[5786b41d6dda3288]::types::ImproperCTypesVisitor>::check_type_for_ffi.cold.0
  24:     0x7f133a2a2e60 - <rustc_lint[5786b41d6dda3288]::types::ImproperCTypesVisitor>::check_type_for_ffi_and_report_errors
  25:     0x7f133a2a3346 - <rustc_lint[5786b41d6dda3288]::types::ImproperCTypesVisitor>::check_foreign_fn
  26:     0x7f133a7ab0a9 - <rustc_lint[5786b41d6dda3288]::BuiltinCombinedModuleLateLintPass as rustc_lint[5786b41d6dda3288]::passes::LateLintPass>::check_fn
  27:     0x7f133a37e112 - <rustc_lint[5786b41d6dda3288]::late::LateContextAndPass<rustc_lint[5786b41d6dda3288]::BuiltinCombinedModuleLateLintPass> as rustc_hir[bf0ffd38f13728af]::intravisit::Visitor>::visit_nested_item
  28:     0x7f133a37c519 - rustc_lint[5786b41d6dda3288]::lint_mod
  29:     0x7f133a37c317 - rustc_query_impl[921380be43ec1358]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[921380be43ec1358]::query_impl::lint_mod::dynamic_query::{closure#2}::{closure#0}, rustc_middle[71d5f388b7d1fdf2]::query::erase::Erased<[u8; 0usize]>>
  30:     0x7f133ac01ced - rustc_query_system[1909eca902444a27]::query::plumbing::try_execute_query::<rustc_query_impl[921380be43ec1358]::DynamicConfig<rustc_query_system[1909eca902444a27]::query::caches::DefaultCache<rustc_span[9f840697e39ebf3c]::def_id::LocalModDefId, rustc_middle[71d5f388b7d1fdf2]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[921380be43ec1358]::plumbing::QueryCtxt, false>
  31:     0x7f133ac005ff - rustc_query_impl[921380be43ec1358]::query_impl::lint_mod::get_query_non_incr::__rust_end_short_backtrace
  32:     0x7f133ac0019f - rustc_lint[5786b41d6dda3288]::late::check_crate::{closure#1}
  33:     0x7f133abffb9e - rustc_lint[5786b41d6dda3288]::late::check_crate
  34:     0x7f133abf9aa5 - rustc_interface[5d7beb8844659dcb]::passes::analysis
  35:     0x7f133abf8799 - rustc_query_impl[921380be43ec1358]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[921380be43ec1358]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[71d5f388b7d1fdf2]::query::erase::Erased<[u8; 1usize]>>
  36:     0x7f133ad25443 - rustc_query_system[1909eca902444a27]::query::plumbing::try_execute_query::<rustc_query_impl[921380be43ec1358]::DynamicConfig<rustc_query_system[1909eca902444a27]::query::caches::SingleCache<rustc_middle[71d5f388b7d1fdf2]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[921380be43ec1358]::plumbing::QueryCtxt, false>
  37:     0x7f133ad251bf - rustc_query_impl[921380be43ec1358]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  38:     0x7f133ad34696 - rustc_interface[5d7beb8844659dcb]::interface::run_compiler::<core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>, rustc_driver_impl[7f540b76ed15adf]::run_compiler::{closure#0}>::{closure#0}
  39:     0x7f133afc4a45 - std[67003dfa8d3cf222]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[5d7beb8844659dcb]::util::run_in_thread_with_globals<rustc_interface[5d7beb8844659dcb]::util::run_in_thread_pool_with_globals<rustc_interface[5d7beb8844659dcb]::interface::run_compiler<core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>, rustc_driver_impl[7f540b76ed15adf]::run_compiler::{closure#0}>::{closure#0}, core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>>::{closure#0}, core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>>
  40:     0x7f133afc4872 - <<std[67003dfa8d3cf222]::thread::Builder>::spawn_unchecked_<rustc_interface[5d7beb8844659dcb]::util::run_in_thread_with_globals<rustc_interface[5d7beb8844659dcb]::util::run_in_thread_pool_with_globals<rustc_interface[5d7beb8844659dcb]::interface::run_compiler<core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>, rustc_driver_impl[7f540b76ed15adf]::run_compiler::{closure#0}>::{closure#0}, core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>>::{closure#0}, core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e4f656a50871fc5f]::result::Result<(), rustc_span[9f840697e39ebf3c]::ErrorGuaranteed>>::{closure#1} as core[e4f656a50871fc5f]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  41:     0x7f1335d99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hd7bd2141211518c4
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/alloc/src/boxed.rs:2016:9
  42:     0x7f1335d99725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h21602226b6e0c057
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/alloc/src/boxed.rs:2016:9
  43:     0x7f1335d99725 - std::sys::pal::unix::thread::Thread::new::thread_start::h41536a58e5007e48
                               at /rustc/52cea084bd5bbac12ecfa5c0499f5c777025c968/library/std/src/sys/pal/unix/thread.rs:108:17
  44:     0x7f1335b819eb - <unknown>
  45:     0x7f1335c057cc - <unknown>
  46:                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: rustc 1.78.0-nightly (52cea084b 2024-02-23) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z dump-mir-dir=dir

query stack during panic:
#0 [lint_mod] linting top-level module
#1 [analysis] running analysis passes on this crate
end of query stack
error[E0433]: failed to resolve: use of undeclared crate or module `libc`
 --> /tmp/icemaker_global_tempdir.D7QMTMHKPUt0/rustc_testrunner_tmpdir_reporting.UDMzaOZ6XWcn/mvce.rs:3:27
  |
3 | pub extern "C" fn cb() -> libc::uintptr_t {}
  |                           ^^^^ use of undeclared crate or module `libc`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0433`.

[matthiaskrgr]

#121206 cc @nnethercote