Rustc crashes at compiler/rustc_middle/src/ty/generics.rs:223:29 caused by index out of bounds

[wangbo15]

Code

This one is also highly similar to #136138 and #136139, which is caused by the first line #!feature(intrinsics)]. Still, based on their different stack traces and triggered assertions, I think this is a new one.

#![feature(intrinsics)]
fn main() {
    transmute();
}
extern "rust-intrinsic" fn transmute() {
}

Meta

rustc --version --verbose:

rustc 1.86.0-nightly (f85c6de55 2025-01-26)
binary: rustc
commit-hash: f85c6de55206dbee5ffedfd821df1503a7b92346
commit-date: 2025-01-26
host: x86_64-unknown-linux-gnu
release: 1.86.0-nightly
LLVM version: 19.1.7

Error output

warning: the feature `intrinsics` is internal to the compiler or standard library
 --> 3.rs:1:12
  |
1 | #![feature(intrinsics)]
  |            ^^^^^^^^^^
  |
  = note: using it is strongly discouraged
  = note: `#[warn(internal_features)]` on by default


thread 'rustc' panicked at compiler/rustc_middle/src/ty/generics.rs:223:29:
index out of bounds: the len is 0 but the index is 0
stack backtrace:
   0:     0x7fb6a6460210 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hec9bc6463e252640
   1:     0x7fb6a6cd0ee6 - core::fmt::write::h962cad0079919c7e
   2:     0x7fb6a7bcec51 - std::io::Write::write_fmt::h081e59591f35f868
   3:     0x7fb6a6460072 - std::sys::backtrace::BacktraceLock::print::he0deffbd85e9a2c5
   4:     0x7fb6a64624f2 - std::panicking::default_hook::{{closure}}::h99776b3a5456e866
   5:     0x7fb6a646237a - std::panicking::default_hook::hcad38b9ed4b5517d
   6:     0x7fb6a5617279 - std[cc940dec3ff43b12]::panicking::update_hook::<alloc[5f7a888829935c2b]::boxed::Box<rustc_driver_impl[af2bdb3744899392]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x7fb6a6463073 - std::panicking::rust_panic_with_hook::hbfeeff1ab3569ba1
   8:     0x7fb6a6462d6a - std::panicking::begin_panic_handler::{{closure}}::h32c93c4f5d28ab99
   9:     0x7fb6a64606e9 - std::sys::backtrace::__rust_end_short_backtrace::h1884c239824d44f7
  10:     0x7fb6a6462a2d - rust_begin_unwind
  11:     0x7fb6a30f5bd0 - core::panicking::panic_fmt::he58927c3c03479ba
  12:     0x7fb6a4d3db79 - core::panicking::panic_bounds_check::hc63b12e46b4e3bca
  13:     0x7fb6a89c7553 - <rustc_middle[ea35cf57050946b4]::ty::generics::Generics>::param_at.cold
  14:     0x7fb6a57bcae6 - rustc_hir_analysis[ce12ae6d63b57b8a]::check::intrinsic::check_intrinsic_type
  15:     0x7fb6a72f3686 - rustc_hir_analysis[ce12ae6d63b57b8a]::check::wfcheck::check_well_formed
  16:     0x7fb6a72f2247 - rustc_query_impl[52b9445d4dcf70be]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[52b9445d4dcf70be]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[ea35cf57050946b4]::query::erase::Erased<[u8; 1usize]>>
  17:     0x7fb6a72f1ce9 - rustc_query_system[b5c6449b7ccd2566]::query::plumbing::try_execute_query::<rustc_query_impl[52b9445d4dcf70be]::DynamicConfig<rustc_data_structures[aef26e4d10f0fc6d]::vec_cache::VecCache<rustc_span[d5a27b28009c9e0]::def_id::LocalDefId, rustc_middle[ea35cf57050946b4]::query::erase::Erased<[u8; 1usize]>, rustc_query_system[b5c6449b7ccd2566]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[52b9445d4dcf70be]::plumbing::QueryCtxt, false>
  18:     0x7fb6a72f1746 - rustc_query_impl[52b9445d4dcf70be]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  19:     0x7fb6a72ef36c - rustc_hir_analysis[ce12ae6d63b57b8a]::check::wfcheck::check_mod_type_wf
  20:     0x7fb6a72ef18b - rustc_query_impl[52b9445d4dcf70be]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[52b9445d4dcf70be]::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[ea35cf57050946b4]::query::erase::Erased<[u8; 1usize]>>
  21:     0x7fb6a7bd6ac8 - rustc_query_system[b5c6449b7ccd2566]::query::plumbing::try_execute_query::<rustc_query_impl[52b9445d4dcf70be]::DynamicConfig<rustc_query_system[b5c6449b7ccd2566]::query::caches::DefaultCache<rustc_span[d5a27b28009c9e0]::def_id::LocalModDefId, rustc_middle[ea35cf57050946b4]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[52b9445d4dcf70be]::plumbing::QueryCtxt, false>
  22:     0x7fb6a7bd6870 - rustc_query_impl[52b9445d4dcf70be]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
  23:     0x7fb6a705b1e6 - rustc_hir_analysis[ce12ae6d63b57b8a]::check_crate
  24:     0x7fb6a7057aa2 - rustc_interface[d0d5d02e7a56d74f]::passes::run_required_analyses
  25:     0x7fb6a7bca35e - rustc_interface[d0d5d02e7a56d74f]::passes::analysis
  26:     0x7fb6a7bca32f - rustc_query_impl[52b9445d4dcf70be]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[52b9445d4dcf70be]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[ea35cf57050946b4]::query::erase::Erased<[u8; 0usize]>>
  27:     0x7fb6a7bb7315 - rustc_query_system[b5c6449b7ccd2566]::query::plumbing::try_execute_query::<rustc_query_impl[52b9445d4dcf70be]::DynamicConfig<rustc_query_system[b5c6449b7ccd2566]::query::caches::SingleCache<rustc_middle[ea35cf57050946b4]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[52b9445d4dcf70be]::plumbing::QueryCtxt, false>
  28:     0x7fb6a7bb704e - rustc_query_impl[52b9445d4dcf70be]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  29:     0x7fb6a7bdd429 - rustc_interface[d0d5d02e7a56d74f]::passes::create_and_enter_global_ctxt::<core[c1de5c9ad145c0db]::option::Option<rustc_interface[d0d5d02e7a56d74f]::queries::Linker>, rustc_driver_impl[af2bdb3744899392]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  30:     0x7fb6a7c28213 - rustc_interface[d0d5d02e7a56d74f]::interface::run_compiler::<(), rustc_driver_impl[af2bdb3744899392]::run_compiler::{closure#0}>::{closure#1}
  31:     0x7fb6a7b24eb5 - std[cc940dec3ff43b12]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[d0d5d02e7a56d74f]::util::run_in_thread_with_globals<rustc_interface[d0d5d02e7a56d74f]::util::run_in_thread_pool_with_globals<rustc_interface[d0d5d02e7a56d74f]::interface::run_compiler<(), rustc_driver_impl[af2bdb3744899392]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  32:     0x7fb6a7b24b99 - <<std[cc940dec3ff43b12]::thread::Builder>::spawn_unchecked_<rustc_interface[d0d5d02e7a56d74f]::util::run_in_thread_with_globals<rustc_interface[d0d5d02e7a56d74f]::util::run_in_thread_pool_with_globals<rustc_interface[d0d5d02e7a56d74f]::interface::run_compiler<(), rustc_driver_impl[af2bdb3744899392]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[c1de5c9ad145c0db]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  33:     0x7fb6a7b2432b - std::sys::pal::unix::thread::Thread::new::thread_start::hb22e947f5885a296
  34:     0x7fb6a1e7a609 - start_thread
                               at /build/glibc-LcI20x/glibc-2.31/nptl/pthread_create.c:477:8
  35:     0x7fb6a1d9f353 - clone
                               at /build/glibc-LcI20x/glibc-2.31/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95:0
  36:                0x0 - <unknown>

error: the compiler unexpectedly panicked. this is a bug.

note: using internal features is not supported and expected to cause internal compiler errors when used incorrectly

note: please attach the file at `/home/nightwish/workspace/compiler/rust_test/2025-01-23/rustc-ice-2025-01-27T15_19_25-25784.txt` to your bug report

query stack during panic:
#0 [check_well_formed] checking that `transmute` is well-formed
#1 [check_mod_type_wf] checking that types are well-formed in top-level module
... and 1 other queries... use `env RUST_BACKTRACE=1` to see the full query stack
warning: 1 warning emitted

Backtrace

<backtrace>

[cyrgani]

Intrinsics are an internal feature and AFAIK ICEs when misusing it are expected and won't be fixed (note: using internal features is not supported and expected to cause internal compiler errors when used incorrectly is also at the bottom of the backtrace.)

[compiler-errors]

@cyrgani is correct.