Internal Status Access Violation with constant redefinition

[TheIronBorn]

Code

const FOO: usize = 32;
fn bar() {
    const FOO: usize = FOO;
}

Meta

rustc --version --verbose:

rustc 1.86.0-nightly (ed43cbcb8 2025-01-21)
binary: rustc
commit-hash: ed43cbcb882e7c06870abdd9305dc1f17eb9bab9
commit-date: 2025-01-21
host: x86_64-pc-windows-msvc
release: 1.86.0-nightly
LLVM version: 19.1.7

Error output

error: could not compile `testtest` (lib)

Caused by:
process didn't exit successfully: `C:\Users\<username>\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\bin\clippy-driver.exe C:\Users\<username>\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\bin\rustc.exe --crate-name testtest --edition=2024 src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata -C embed-bitcode=no -C debuginfo=2 -Ctarget-cpu=native -Ztune-cpu=native -Ctarget-feature=+aes -Clink-arg=-fuse-ld=lld -Zthreads=4 --cfg "feature=\"default\"" --check-cfg cfg(docsrs,test) --check-cfg "cfg(feature, values(\"default\", \"rand\"))" -C metadata=10a1d148f727b426 -C extra-filename=-652f9f02f745d5a0 --out-dir C:\Users\<username>\Rust_stuff\misc\testtest\target\debug\deps -C incremental=C:\Users\<username>\Rust_stuff\misc\testtest\target\debug\incremental -L dependency=C:\Users\<username>\Rust_stuff\misc\testtest\target\debug\deps` (exit code: 0xc0000005, STATUS_ACCESS_VIOLATION)

[bjorn3]

On the playground both stable and nightly give:

error[E0391]: cycle detected when simplifying constant for the type system `bar::FOO`
 --> src/lib.rs:3:5
  |
3 |     const FOO: usize = FOO;
  |     ^^^^^^^^^^^^^^^^
  |
note: ...which requires const-evaluating + checking `bar::FOO`...
 --> src/lib.rs:3:24
  |
3 |     const FOO: usize = FOO;
  |                        ^^^
  = note: ...which again requires simplifying constant for the type system `bar::FOO`, completing the cycle
  = note: cycle used when running analysis passes on this crate
  = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

For more information about this error, try `rustc --explain E0391`.
error: could not compile `playground` (lib) due to 1 previous error

[ehuss]

@bjorn3 there are several non-standard flags in the user's output:
-Ctarget-cpu=native -Ztune-cpu=native -Ctarget-feature=+aes -Clink-arg=-fuse-ld=lld -Zthreads=4

I believe it is the -Zthreads=4 which is causing the error.

[bjorn3]

Didn't notice that. -Zthreads=4 indeed gives a different result:

https://rust.godbolt.org/z/nqfqqjo8h

thread 'rustc query cycle handler' panicked at compiler/rustc_query_system/src/query/job.rs:502:9:
deadlock detected as we're unable to find a query cycle to break
current query map:
{}
stack backtrace:
   0:     0x7a4ec02fa8ca - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hd3f7dde65eadb8f5
   1:     0x7a4ec0a12da6 - core::fmt::write::h03821e8dd27929da
   2:     0x7a4ec19846d1 - std::io::Write::write_fmt::h28497d2928023bec
   3:     0x7a4ec02fa722 - std::sys::backtrace::BacktraceLock::print::h113e8531332c9d1a
   4:     0x7a4ec02fcba2 - std::panicking::default_hook::{{closure}}::h511fb590fa3e0372
   5:     0x7a4ec02fca2a - std::panicking::default_hook::h9dd552201bc7892d
   6:     0x7a4ebf45ad0b - std[99f071fb7bf80049]::panicking::update_hook::<alloc[8b0936adf4c1bb8e]::boxed::Box<rustc_driver_impl[520997e00060abd5]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x7a4ec02fd723 - std::panicking::rust_panic_with_hook::hdf22da07ff72d33d
   8:     0x7a4ec02fd41a - std::panicking::begin_panic_handler::{{closure}}::h6388cd95efa89156
   9:     0x7a4ec02fada9 - std::sys::backtrace::__rust_end_short_backtrace::ha958cfab6971d37c
  10:     0x7a4ec02fd0dd - rust_begin_unwind
  11:     0x7a4ebcfa9690 - core::panicking::panic_fmt::hba7dd8f296a53b9a
  12:     0x7a4ebfe994aa - rustc_query_system[3ed4f24c27dcb839]::query::job::break_query_cycles
  13:     0x7a4ebf4515cc - std[99f071fb7bf80049]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[686a4ed24023fb80]::util::run_in_thread_pool_with_globals<rustc_interface[686a4ed24023fb80]::interface::run_compiler<(), rustc_driver_impl[520997e00060abd5]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#2}::{closure#1}, ()>
  14:     0x7a4ebf462938 - <<std[99f071fb7bf80049]::thread::Builder>::spawn_unchecked_<rustc_interface[686a4ed24023fb80]::util::run_in_thread_pool_with_globals<rustc_interface[686a4ed24023fb80]::interface::run_compiler<(), rustc_driver_impl[520997e00060abd5]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#2}::{closure#1}, ()>::{closure#1} as core[fe4dc82ac4f8e512]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  15:     0x7a4ec185352b - std::sys::pal::unix::thread::Thread::new::thread_start::h3a1166e57f630f50
  16:     0x7a4ebba94ac3 - <unknown>
  17:     0x7a4ebbb26850 - <unknown>
  18:                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 make sure that you have updated to the latest nightly

note: please attach the file at `/app/rustc-ice-2025-01-22T15_12_31-1.txt` to your bug report

note: compiler flags: -C debuginfo=2 -C llvm-args=--x86-asm-syntax=intel --crate-type rlib -Z threads=4

query stack during panic:
end of query stack
query cycle handler thread panicked, aborting process
error: rustc interrupted by SIGSEGV, printing backtrace

/opt/compiler-explorer/rust-nightly/lib/librustc_driver-51e8a964a3a70cd7.so(+0x367f363)[0x7a4ebf47f363]
/lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7a4ebba42520]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x178)[0x7a4ebba28898]
/opt/compiler-explorer/rust-nightly/lib/librustc_driver-51e8a964a3a70cd7.so(+0x2ad801a)[0x7a4ebe8d801a]
/opt/compiler-explorer/rust-nightly/lib/librustc_driver-51e8a964a3a70cd7.so(+0x44f89da)[0x7a4ec02f89da]
/opt/compiler-explorer/rust-nightly/lib/librustc_driver-51e8a964a3a70cd7.so(_RINvNtNtCsddpJ6axtn8j_3std3sys9backtrace28___rust_begin_short_backtraceNCNCINvNtCs8XNBdZ1EPrU_15rustc_interface4util31run_in_thread_pool_with_globalsNCINvNtB1g_9interface12run_compileruNCNvCs72GnytMAHAL_17rustc_driver_impl12run_compiler0Es_0uEs0_0s_0uEB31_+0x79)[0x7a4ebf451619]
/opt/compiler-explorer/rust-nightly/lib/librustc_driver-51e8a964a3a70cd7.so(+0x3662938)[0x7a4ebf462938]
/opt/compiler-explorer/rust-nightly/lib/librustc_driver-51e8a964a3a70cd7.so(+0x5a5352b)[0x7a4ec185352b]
/lib/x86_64-linux-gnu/libc.so.6(+0x94ac3)[0x7a4ebba94ac3]
/lib/x86_64-linux-gnu/libc.so.6(+0x126850)[0x7a4ebbb26850]

note: we would appreciate a report at https://github.com/rust-lang/rust
help: you can increase rustc's stack size by setting RUST_MIN_STACK=16777216
Program terminated with signal: SIGSEGV
Compiler returned: 139

[ehuss]

Another oddity is that I get SIGSEGV on aarch64-apple-darwin and STATUS_ACCESS_VIOLATION on x86_64-pc-windows-msvc, but I get the deadlock detection on x86_64-apple-darwin.

[cyrgani]

Reduction (rustc -Zthreads=2):

const FOO: usize = FOO;

Bisection:

searched nightlies: from nightly-2024-12-16 to nightly-2025-01-22
regressed nightly: nightly-2024-12-18
searched commit range: 6d9f6ae...a4cb3c8
regressed commit: 978c659

bisected with cargo-bisect-rustc v0.6.9

Host triple: x86_64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --start=2024-12-16 --script run.sh 

@rustbot label:S-has-mcve WG-compiler-parallel S-has-bisection

[lqd]

That bisects to removing driver queries? @bjorn3

[bjorn3]

That PR touched some code around handling of fatal error when they were emitted from inside a TyCtxt.