ICE error: Assertion failed in `compiler/rustc_ty_utils/src/instance.rs:103:13`

[iamanonymouscs]

Code

cat code.rs

fn main() {
    let mut it = (Empty);
    rec(&mut it);
}

struct Empty;

impl Iterator for Empty {
    type Item = ();
    fn next<'a>(&'a mut self) -> core::option::Option<()> {
        None
    }
}

fn identity<T>(x: T) -> T {
    x
}

fn rec<T>(mut it: T)
where
    T: Iterator,
{
    if () == () {
        T::count(it);
    } else {
        rec(identity(&mut it))
    }
}

Meta

rustc --version --verbose:

rustc 1.75.0-nightly (7adc89b69 2023-11-07)
binary: rustc
commit-hash: 7adc89b69b941afceadcf8609dd6b2999353e550
commit-date: 2023-11-07
host: x86_64-unknown-linux-gnu
release: 1.75.0-nightly
LLVM version: 17.0.4

The same problem is reproduced on the stable version(1.73.0 cc66ad468 2023-10-03)

Error output

rustc code.rs

warning: unnecessary parentheses around assigned value
 --> code.rs:2:18
  |
2 |     let mut it = (Empty);
  |                  ^     ^
  |
  = note: `#[warn(unused_parens)]` on by default
help: remove these parentheses
  |
2 -     let mut it = (Empty);
2 +     let mut it = Empty;
  |

thread 'rustc' panicked at compiler/rustc_ty_utils/src/instance.rs:103:13:
assertion failed: !rcvr_args.has_infer()

Backtrace

stack backtrace:
   0:     0x7f05b0cf1cfc - std::backtrace_rs::backtrace::libunwind::trace::h5537bbd154806f59
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f05b0cf1cfc - std::backtrace_rs::backtrace::trace_unsynchronized::hc161d98f857540db
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f05b0cf1cfc - std::sys_common::backtrace::_print_fmt::h4c1c3b705b28156a
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x7f05b0cf1cfc - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h0307538b827551fd
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f05b0d53f20 - core::fmt::rt::Argument::fmt::h478ea729acec0585
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/core/src/fmt/rt.rs:142:9
   5:     0x7f05b0d53f20 - core::fmt::write::hd245c5370776cdd5
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/core/src/fmt/mod.rs:1117:17
   6:     0x7f05b0ce5c1f - std::io::Write::write_fmt::hfbfb5cc218327f78
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/io/mod.rs:1763:15
   7:     0x7f05b0cf1ae4 - std::sys_common::backtrace::_print::hb0911569cc7c7f62
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f05b0cf1ae4 - std::sys_common::backtrace::print::h726d39a9d4ba5a1b
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f05b0cf4777 - std::panicking::default_hook::{{closure}}::h82ba92f7be888d70
  10:     0x7f05b0cf44df - std::panicking::default_hook::hc218ff80dc9e4cd7
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/panicking.rs:292:9
  11:     0x7f05b3a2e7c0 - std[3218d6cd77b0d06f]::panicking::update_hook::<alloc[b3fb55f8a078529e]::boxed::Box<rustc_driver_impl[ddf04b8681d0fb7f]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f05b0cf4eb8 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hfd09a4f105e6083e
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/alloc/src/boxed.rs:2021:9
  13:     0x7f05b0cf4eb8 - std::panicking::rust_panic_with_hook::h0290e6db2f0dd7a2
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/panicking.rs:783:13
  14:     0x7f05b0cf4bd9 - std::panicking::begin_panic_handler::{{closure}}::h7a45355f37d0a7a0
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/panicking.rs:649:13
  15:     0x7f05b0cf21c6 - std::sys_common::backtrace::__rust_end_short_backtrace::hefe3cc14b81c89c0
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/sys_common/backtrace.rs:170:18
  16:     0x7f05b0cf4972 - rust_begin_unwind
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/panicking.rs:645:5
  17:     0x7f05b0d50645 - core::panicking::panic_fmt::h46033962df62bf84
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/core/src/panicking.rs:72:14
  18:     0x7f05b0d506e3 - core::panicking::panic::h3df56cba124c6fd8
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/core/src/panicking.rs:127:5
  19:     0x7f05b2664830 - rustc_ty_utils[960730023ce9d82d]::instance::resolve_instance
  20:     0x7f05b4c49769 - rustc_query_impl[4e47b2e9cc97378d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[4e47b2e9cc97378d]::query_impl::resolve_instance::dynamic_query::{closure#2}::{closure#0}, rustc_middle[1d9f98b98706d2de]::query::erase::Erased<[u8; 32usize]>>
  21:     0x7f05b4c49aab - rustc_query_system[42a82f5a7de036a2]::query::plumbing::try_execute_query::<rustc_query_impl[4e47b2e9cc97378d]::DynamicConfig<rustc_query_system[42a82f5a7de036a2]::query::caches::DefaultCache<rustc_middle[1d9f98b98706d2de]::ty::ParamEnvAnd<(rustc_span[84fcc9c9f755a0da]::def_id::DefId, &rustc_middle[1d9f98b98706d2de]::ty::list::List<rustc_middle[1d9f98b98706d2de]::ty::generic_args::GenericArg>)>, rustc_middle[1d9f98b98706d2de]::query::erase::Erased<[u8; 32usize]>>, false, false, false>, rustc_query_impl[4e47b2e9cc97378d]::plumbing::QueryCtxt, false>
  22:     0x7f05b4c496e1 - rustc_query_impl[4e47b2e9cc97378d]::query_impl::resolve_instance::get_query_non_incr::__rust_end_short_backtrace
  23:     0x7f05b4c46565 - <rustc_middle[1d9f98b98706d2de]::ty::instance::Instance>::expect_resolve
  24:     0x7f05b2b78b5d - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec::{closure#0}
  25:     0x7f05b5b330df - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  26:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  27:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  28:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  29:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  30:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  31:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  32:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  33:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  34:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  35:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  36:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  37:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  38:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  39:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  40:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  41:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  42:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  43:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  44:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  45:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  46:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  47:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  48:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  49:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  50:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  51:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  52:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  53:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  54:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  55:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  56:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  57:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  58:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  59:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  60:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  61:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  62:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  63:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  64:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  65:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  66:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  67:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  68:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  69:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  70:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  71:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  72:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  73:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  74:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
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  90:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  91:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  92:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  93:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  94:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  95:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  96:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  97:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  98:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
  99:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
 100:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
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 152:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
 153:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
 154:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
 155:     0x7f05b5b335da - rustc_monomorphize[1593c952df30dad4]::collector::collect_items_rec
 156:     0x7f05b5b2ec94 - rustc_monomorphize[1593c952df30dad4]::partitioning::collect_and_partition_mono_items
 157:     0x7f05b5b2dfe4 - rustc_query_impl[4e47b2e9cc97378d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[4e47b2e9cc97378d]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2}::{closure#0}, rustc_middle[1d9f98b98706d2de]::query::erase::Erased<[u8; 24usize]>>
 158:     0x7f05b5b2dfc9 - <rustc_query_impl[4e47b2e9cc97378d]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2} as core[8a68bd8e0f0c6481]::ops::function::FnOnce<(rustc_middle[1d9f98b98706d2de]::ty::context::TyCtxt, ())>>::call_once
 159:     0x7f05b5b2d5c7 - rustc_query_system[42a82f5a7de036a2]::query::plumbing::try_execute_query::<rustc_query_impl[4e47b2e9cc97378d]::DynamicConfig<rustc_query_system[42a82f5a7de036a2]::query::caches::SingleCache<rustc_middle[1d9f98b98706d2de]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[4e47b2e9cc97378d]::plumbing::QueryCtxt, false>
 160:     0x7f05b5b2d2c9 - rustc_query_impl[4e47b2e9cc97378d]::query_impl::collect_and_partition_mono_items::get_query_non_incr::__rust_end_short_backtrace
 161:     0x7f05b54d6f4e - rustc_codegen_ssa[1aedc3416d28b980]::base::codegen_crate::<rustc_codegen_llvm[4f6287d33c037344]::LlvmCodegenBackend>
 162:     0x7f05b54d6bfa - <rustc_codegen_llvm[4f6287d33c037344]::LlvmCodegenBackend as rustc_codegen_ssa[1aedc3416d28b980]::traits::backend::CodegenBackend>::codegen_crate
 163:     0x7f05b54d5297 - rustc_interface[c2a09eed6a0b2444]::passes::start_codegen
 164:     0x7f05b54d4c63 - <rustc_interface[c2a09eed6a0b2444]::queries::Queries>::ongoing_codegen
 165:     0x7f05b5b49085 - rustc_interface[c2a09eed6a0b2444]::interface::run_compiler::<core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>, rustc_driver_impl[ddf04b8681d0fb7f]::run_compiler::{closure#1}>::{closure#0}
 166:     0x7f05b5b76dca - std[3218d6cd77b0d06f]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[c2a09eed6a0b2444]::util::run_in_thread_with_globals<rustc_interface[c2a09eed6a0b2444]::util::run_in_thread_pool_with_globals<rustc_interface[c2a09eed6a0b2444]::interface::run_compiler<core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>, rustc_driver_impl[ddf04b8681d0fb7f]::run_compiler::{closure#1}>::{closure#0}, core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>>::{closure#0}, core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>>
 167:     0x7f05b5b76bf3 - <<std[3218d6cd77b0d06f]::thread::Builder>::spawn_unchecked_<rustc_interface[c2a09eed6a0b2444]::util::run_in_thread_with_globals<rustc_interface[c2a09eed6a0b2444]::util::run_in_thread_pool_with_globals<rustc_interface[c2a09eed6a0b2444]::interface::run_compiler<core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>, rustc_driver_impl[ddf04b8681d0fb7f]::run_compiler::{closure#1}>::{closure#0}, core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>>::{closure#0}, core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[8a68bd8e0f0c6481]::result::Result<(), rustc_span[84fcc9c9f755a0da]::ErrorGuaranteed>>::{closure#1} as core[8a68bd8e0f0c6481]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
 168:     0x7f05b0cffc25 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hafee0634ee8690ea
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/alloc/src/boxed.rs:2007:9
 169:     0x7f05b0cffc25 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h23cfdaad852345bd
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/alloc/src/boxed.rs:2007:9
 170:     0x7f05b0cffc25 - std::sys::unix::thread::Thread::new::thread_start::h8311638266b07778
                               at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/library/std/src/sys/unix/thread.rs:108:17
 171:     0x7f05b0bee609 - start_thread
 172:     0x7f05b0b11133 - clone
 173:                0x0 - <unknown>

error: 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: please attach the file at `/home/rustc-ice-2023-11-08T01_42_21-6589.txt` to your bug report

query stack during panic:
thread panicked while processing panic. aborting.
Aborted (core dumped)

[DaniPopes]

Minimal:

fn main() {
    rec(&mut None::<()>.into_iter());
}

fn rec<T: Iterator>(mut it: T) {
    if true {
        it.next();
    } else {
        rec(&mut it);
    }
}

Interestingly, another assertion fails when using -C incremental (Cargo):

thread 'rustc' panicked at /rustc/7adc89b69b941afceadcf8609dd6b2999353e550/compiler/rustc_type_ir/src/ty_kind.rs:844:17:
type variables should not be hashed: ?0t

rustc-ice-2023-11-08T10_44_03-358826.txt

---

Both ICEs:

$ cargo bisect-rustc --start 2017-08-14 --regress ice
$ cargo bisect-rustc --start 2017-08-14 --regress ice --without-cargo --script=rustc -- src/main.rs

searched toolchains nightly-2017-08-14 through nightly-2023-11-08
Regression in nightly-2023-04-16

found 10 bors merge commits in the specified range
commit[0] 2023-04-14: Auto merge of #110331 - matthiaskrgr:rollup-9vldvow, r=matthiaskrgr
commit[1] 2023-04-14: Auto merge of #110197 - cjgillot:codegen-discr, r=pnkfelix
commit[2] 2023-04-15: Auto merge of #110142 - Mark-Simulacrum:reduce-core-counts, r=pietroalbini
commit[3] 2023-04-15: Auto merge of #109802 - notriddle:notriddle/rustdoc-search-generics-nested, r=GuillaumeGomez
commit[4] 2023-04-15: Auto merge of #110335 - asomers:rust-gdb-freebsd, r=jyn514
commit[5] 2023-04-15: Auto merge of #109900 - cjgillot:disable-const-prop, r=oli-obk
commit[6] 2023-04-15: Auto merge of #110323 - lcnr:dropck-uwu, r=compiler-errors
commit[7] 2023-04-15: Auto merge of #110349 - rust-lang:pa-bump-1.71.0, r=pietroalbini
commit[8] 2023-04-15: Auto merge of #110227 - klensy:bs-win, r=Mark-Simulacrum
commit[9] 2023-04-15: Auto merge of #110361 - ehuss:disable-jobserver-error, r=Mark-Simulacrum

[iamanonymouscs]

Another test case:

fn main() {
    rec(&mut Empty);
}
struct Empty;
impl Iterator for Empty {
    type Item = ();
    fn next<'a>(&'a mut self) -> core::option::Option<()> {
        None
    }
}
fn identity<T>(x: T) -> T {
    x
}
fn rec<T>(mut it: T)
where
    T: Iterator,
{
    if () == () {
        T::count(it);
    } else {
        rec(identity(&mut it))
    }
}