ice gce after unsilencing followup errors

[matthiaskrgr]

Code

#![feature(generic_const_exprs)]

const fn t<const N: usize>() -> u8 {
    N as u8
}

#[repr(u8)]
enum T<const N: u8 = { T::<0>::A as u8 + T::<0>::B as u8 }>
where
    [(); N as usize]:
{
    A = t::<N>() as u8, B
}

before #117449

error: generic parameters may not be used in enum discriminant values
  --> a.rs:12:13
   |
12 |     A = t::<N>() as u8, B
   |             ^ cannot perform const operation using `N`
   |
   = note: const parameters may not be used in enum discriminant values

warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
 --> a.rs:1:12
  |
1 | #![feature(generic_const_exprs)]
  |            ^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0601]: `main` function not found in crate `a`
  --> a.rs:13:2
   |
13 | }
   |  ^ consider adding a `main` function to `a.rs`

error[E0747]: unresolved item provided when a constant was expected
  --> a.rs:12:13
   |
12 |     A = t::<N>() as u8, B
   |             ^
   |
help: if this generic argument was intended as a const parameter, surround it with braces
   |
12 |     A = t::<{ N }>() as u8, B
   |             +   +

error: aborting due to 3 previous errors; 1 warning emitted

Some errors have detailed explanations: E0601, E0747.
For more information about an error, try `rustc --explain E0601`.

after #117449

error: generic parameters may not be used in enum discriminant values
  --> a.rs:12:13
   |
12 |     A = t::<N>() as u8, B
   |             ^ cannot perform const operation using `N`
   |
   = note: const parameters may not be used in enum discriminant values

warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
 --> a.rs:1:12
  |
1 | #![feature(generic_const_exprs)]
  |            ^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0601]: `main` function not found in crate `a`
  --> a.rs:13:2
   |
13 | }
   |  ^ consider adding a `main` function to `a.rs`

error[E0747]: unresolved item provided when a constant was expected
  --> a.rs:12:13
   |
12 |     A = t::<N>() as u8, B
   |             ^
   |
help: if this generic argument was intended as a const parameter, surround it with braces
   |
12 |     A = t::<{ N }>() as u8, B
   |             +   +

error: internal compiler error: compiler/rustc_middle/src/ty/generic_args.rs:940:9: const parameter `N/#0` (N/#0: u8/0) out of range when substituting args=[]

thread 'rustc' panicked at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/compiler/rustc_errors/src/lib.rs:937:30:
Box<dyn Any>
stack backtrace:
   0:     0x7f3378b8c7e6 - std::backtrace_rs::backtrace::libunwind::trace::h0c9ea26daee6c947
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f3378b8c7e6 - std::backtrace_rs::backtrace::trace_unsynchronized::hb1bc1aeb5f61b551
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f3378b8c7e6 - std::sys_common::backtrace::_print_fmt::h094aad19be8ebe6d
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f3378b8c7e6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc6874234e7762746
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f3378bdeec0 - core::fmt::rt::Argument::fmt::hdf2968bdc2925a9e
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/core/src/fmt/rt.rs:142:9
   5:     0x7f3378bdeec0 - core::fmt::write::h8664bf9edaaf2694
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/core/src/fmt/mod.rs:1120:17
   6:     0x7f3378b8014f - std::io::Write::write_fmt::h0eaa39fdf46de86b
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/io/mod.rs:1810:15
   7:     0x7f3378b8c5c4 - std::sys_common::backtrace::_print::hbef740e19ca9f8df
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f3378b8c5c4 - std::sys_common::backtrace::print::h632ce963033ff6b9
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f3378b8f357 - std::panicking::default_hook::{{closure}}::h60c33aff8a33c9d6
  10:     0x7f3378b8f0b9 - std::panicking::default_hook::h5afa325d341c9143
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/panicking.rs:292:9
  11:     0x7f337b958d7c - std[999b1d78adc0d845]::panicking::update_hook::<alloc[69c273dd4ce48d0d]::boxed::Box<rustc_driver_impl[dbdcdc7d37d3e64f]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f3378b8faa6 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h16a7189283919a61
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/alloc/src/boxed.rs:2030:9
  13:     0x7f3378b8faa6 - std::panicking::rust_panic_with_hook::hca001e421e65617b
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/panicking.rs:785:13
  14:     0x7f337b98add4 - std[999b1d78adc0d845]::panicking::begin_panic::<rustc_errors[d7e4352a7b753d34]::ExplicitBug>::{closure#0}
  15:     0x7f337b9876c6 - std[999b1d78adc0d845]::sys_common::backtrace::__rust_end_short_backtrace::<std[999b1d78adc0d845]::panicking::begin_panic<rustc_errors[d7e4352a7b753d34]::ExplicitBug>::{closure#0}, !>
  16:     0x7f337b987336 - std[999b1d78adc0d845]::panicking::begin_panic::<rustc_errors[d7e4352a7b753d34]::ExplicitBug>
  17:     0x7f337b995d21 - <rustc_errors[d7e4352a7b753d34]::diagnostic_builder::BugAbort as rustc_errors[d7e4352a7b753d34]::diagnostic_builder::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7f337bd5d59e - <rustc_errors[d7e4352a7b753d34]::DiagCtxt>::bug::<alloc[69c273dd4ce48d0d]::string::String>
  19:     0x7f337bdf5f8b - rustc_middle[c0a27e9ee4b37138]::util::bug::opt_span_bug_fmt::<rustc_span[1a57749618183ecc]::span_encoding::Span>::{closure#0}
  20:     0x7f337bddeb7a - rustc_middle[c0a27e9ee4b37138]::ty::context::tls::with_opt::<rustc_middle[c0a27e9ee4b37138]::util::bug::opt_span_bug_fmt<rustc_span[1a57749618183ecc]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7f337bddea18 - rustc_middle[c0a27e9ee4b37138]::ty::context::tls::with_context_opt::<rustc_middle[c0a27e9ee4b37138]::ty::context::tls::with_opt<rustc_middle[c0a27e9ee4b37138]::util::bug::opt_span_bug_fmt<rustc_span[1a57749618183ecc]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7f3379d8d1c0 - rustc_middle[c0a27e9ee4b37138]::util::bug::bug_fmt
  23:     0x7f337bdec246 - <rustc_middle[c0a27e9ee4b37138]::ty::generic_args::ArgFolder>::const_param_out_of_range
  24:     0x7f337cc35b76 - <rustc_middle[c0a27e9ee4b37138]::ty::generic_args::ArgFolder as rustc_type_ir[4c7c7cd896c28536]::fold::TypeFolder<rustc_middle[c0a27e9ee4b37138]::ty::context::TyCtxt>>::fold_const
  25:     0x7f337d0619c7 - <&rustc_middle[c0a27e9ee4b37138]::ty::list::List<rustc_middle[c0a27e9ee4b37138]::ty::generic_args::GenericArg> as rustc_type_ir[4c7c7cd896c28536]::fold::TypeFoldable<rustc_middle[c0a27e9ee4b37138]::ty::context::TyCtxt>>::try_fold_with::<rustc_middle[c0a27e9ee4b37138]::ty::generic_args::ArgFolder>
  26:     0x7f337cc35a77 - <rustc_middle[c0a27e9ee4b37138]::ty::generic_args::ArgFolder as rustc_type_ir[4c7c7cd896c28536]::fold::TypeFolder<rustc_middle[c0a27e9ee4b37138]::ty::context::TyCtxt>>::fold_const
  27:     0x7f337cc05af0 - <rustc_middle[c0a27e9ee4b37138]::ty::generic_args::ArgFolder as rustc_type_ir[4c7c7cd896c28536]::fold::TypeFolder<rustc_middle[c0a27e9ee4b37138]::ty::context::TyCtxt>>::fold_ty
  28:     0x7f337cc02364 - <rustc_middle[c0a27e9ee4b37138]::ty::generic_args::GenericArg as rustc_type_ir[4c7c7cd896c28536]::fold::TypeFoldable<rustc_middle[c0a27e9ee4b37138]::ty::context::TyCtxt>>::try_fold_with::<rustc_middle[c0a27e9ee4b37138]::ty::generic_args::ArgFolder>
  29:     0x7f337cc35565 - <rustc_middle[c0a27e9ee4b37138]::ty::Clause as rustc_type_ir[4c7c7cd896c28536]::fold::TypeFoldable<rustc_middle[c0a27e9ee4b37138]::ty::context::TyCtxt>>::try_fold_with::<rustc_middle[c0a27e9ee4b37138]::ty::generic_args::ArgFolder>
  30:     0x7f337cc334ba - <rustc_middle[c0a27e9ee4b37138]::ty::generics::GenericPredicates>::instantiate_into
  31:     0x7f337cdd76ba - <rustc_trait_selection[eaa2cb578abf01d8]::traits::wf::WfPredicates>::nominal_obligations
  32:     0x7f337ce771d0 - <rustc_trait_selection[eaa2cb578abf01d8]::traits::wf::WfPredicates>::compute
  33:     0x7f3379c6b9a2 - <rustc_trait_selection[eaa2cb578abf01d8]::traits::fulfill::FulfillProcessor as rustc_data_structures[b1e775e348ad0e62]::obligation_forest::ObligationProcessor>::process_obligation
  34:     0x7f337cc1517b - <rustc_data_structures[b1e775e348ad0e62]::obligation_forest::ObligationForest<rustc_trait_selection[eaa2cb578abf01d8]::traits::fulfill::PendingPredicateObligation>>::process_obligations::<rustc_trait_selection[eaa2cb578abf01d8]::traits::fulfill::FulfillProcessor>
  35:     0x7f337d2b3ca8 - <rustc_trait_selection[eaa2cb578abf01d8]::traits::engine::ObligationCtxt>::select_all_or_error
  36:     0x7f337cd62b44 - rustc_hir_analysis[f99769aaf9fbe3be]::check::wfcheck::check_type_defn
  37:     0x7f337d30030b - rustc_hir_analysis[f99769aaf9fbe3be]::check::wfcheck::check_well_formed
  38:     0x7f337d2fefb3 - rustc_query_impl[57fa99c9f9bc5eb5]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[57fa99c9f9bc5eb5]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[c0a27e9ee4b37138]::query::erase::Erased<[u8; 1usize]>>
  39:     0x7f337d2fe6b1 - rustc_query_system[a4bae605c4fc5fe8]::query::plumbing::try_execute_query::<rustc_query_impl[57fa99c9f9bc5eb5]::DynamicConfig<rustc_query_system[a4bae605c4fc5fe8]::query::caches::VecCache<rustc_hir[ec81b7385329ac7f]::hir_id::OwnerId, rustc_middle[c0a27e9ee4b37138]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[57fa99c9f9bc5eb5]::plumbing::QueryCtxt, false>
  40:     0x7f337d2fe41b - rustc_query_impl[57fa99c9f9bc5eb5]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  41:     0x7f337d2fbdb7 - rustc_hir_analysis[f99769aaf9fbe3be]::check::wfcheck::check_mod_type_wf
  42:     0x7f337d2fbcfb - rustc_query_impl[57fa99c9f9bc5eb5]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[57fa99c9f9bc5eb5]::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[c0a27e9ee4b37138]::query::erase::Erased<[u8; 1usize]>>
  43:     0x7f337d2faebb - rustc_query_system[a4bae605c4fc5fe8]::query::plumbing::try_execute_query::<rustc_query_impl[57fa99c9f9bc5eb5]::DynamicConfig<rustc_query_system[a4bae605c4fc5fe8]::query::caches::DefaultCache<rustc_span[1a57749618183ecc]::def_id::LocalModDefId, rustc_middle[c0a27e9ee4b37138]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[57fa99c9f9bc5eb5]::plumbing::QueryCtxt, false>
  44:     0x7f337d2fac53 - rustc_query_impl[57fa99c9f9bc5eb5]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
  45:     0x7f337d0e331a - <rustc_middle[c0a27e9ee4b37138]::hir::map::Map>::try_par_for_each_module::<rustc_hir_analysis[f99769aaf9fbe3be]::check_crate::{closure#4}::{closure#0}>::{closure#0}
  46:     0x7f337d0e3b50 - rustc_hir_analysis[f99769aaf9fbe3be]::check_crate
  47:     0x7f337d615619 - rustc_interface[8630123b344ba534]::passes::analysis
  48:     0x7f337d61525f - rustc_query_impl[57fa99c9f9bc5eb5]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[57fa99c9f9bc5eb5]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[c0a27e9ee4b37138]::query::erase::Erased<[u8; 1usize]>>
  49:     0x7f337dbc9524 - rustc_query_system[a4bae605c4fc5fe8]::query::plumbing::try_execute_query::<rustc_query_impl[57fa99c9f9bc5eb5]::DynamicConfig<rustc_query_system[a4bae605c4fc5fe8]::query::caches::SingleCache<rustc_middle[c0a27e9ee4b37138]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[57fa99c9f9bc5eb5]::plumbing::QueryCtxt, false>
  50:     0x7f337dbc9315 - rustc_query_impl[57fa99c9f9bc5eb5]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  51:     0x7f337d950008 - rustc_interface[8630123b344ba534]::interface::run_compiler::<core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>, rustc_driver_impl[dbdcdc7d37d3e64f]::run_compiler::{closure#0}>::{closure#0}
  52:     0x7f337dbee746 - std[999b1d78adc0d845]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[8630123b344ba534]::util::run_in_thread_with_globals<rustc_interface[8630123b344ba534]::util::run_in_thread_pool_with_globals<rustc_interface[8630123b344ba534]::interface::run_compiler<core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>, rustc_driver_impl[dbdcdc7d37d3e64f]::run_compiler::{closure#0}>::{closure#0}, core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>>::{closure#0}, core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>>
  53:     0x7f337dbee573 - <<std[999b1d78adc0d845]::thread::Builder>::spawn_unchecked_<rustc_interface[8630123b344ba534]::util::run_in_thread_with_globals<rustc_interface[8630123b344ba534]::util::run_in_thread_pool_with_globals<rustc_interface[8630123b344ba534]::interface::run_compiler<core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>, rustc_driver_impl[dbdcdc7d37d3e64f]::run_compiler::{closure#0}>::{closure#0}, core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>>::{closure#0}, core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[1ecfc9c7dbf148b3]::result::Result<(), rustc_span[1a57749618183ecc]::ErrorGuaranteed>>::{closure#1} as core[1ecfc9c7dbf148b3]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  54:     0x7f3378b999d5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h75905edabd5878b2
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/alloc/src/boxed.rs:2016:9
  55:     0x7f3378b999d5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hbed8035343ffa301
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/alloc/src/boxed.rs:2016:9
  56:     0x7f3378b999d5 - std::sys::unix::thread::Thread::new::thread_start::hde523d9576990e45
                               at /rustc/94807670a6a3834cc9b71b0b803d49d307c9ba5d/library/std/src/sys/unix/thread.rs:108:17
  57:     0x7f33789459eb - <unknown>
  58:     0x7f33789c97cc - <unknown>
  59:                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: please attach the file at `/tmp/im/rustc-ice-2024-01-10T17_44_55-3921591.txt` to your bug report

query stack during panic:
#0 [check_well_formed] checking that `T` is well-formed
#1 [check_mod_type_wf] checking that types are well-formed in top-level module
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors; 1 warning emitted

Some errors have detailed explanations: E0601, E0747.
For more information about an error, try `rustc --explain E0601`.

cc @oli-obk

[compiler-errors]

This is just another manifestation of the "default param can't reference generics/associated types form the same item". I don't think this needs fixing as long as GCE remains super broken.