Repository: rust
Issue: ICE: issue 84970, `encountered incremental compilation error with evaluate_obligation(4270e020b571106c-835a5b1013d879df)`
Labels: I-ICE,T-compiler,A-incr-comp,C-bug

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### Code
Apologies, I only filed this issue after I already changed the code so I can't remember what state it was.

### Meta
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`rustc --version --verbose`:
```
rustc 1.79.0 (129f3b996 2024-06-10)
binary: rustc
commit-hash: 129f3b9964af4d4a709d1383930ade12dfe7c081
commit-date: 2024-06-10
host: x86_64-unknown-linux-gnu
release: 1.79.0
LLVM version: 18.1.7
```

### Error output

```
error: internal compiler error: encountered incremental compilation error with evaluate_obligation(4270e020b571106c-835a5b1013d879df)
  |
  = help: This is a known issue with the compiler. Run `cargo clean -p midwest_mainline` or `cargo clean` to allow your project to compile
  = note: Please follow the instructions below to create a bug report with the provided information
  = note: See <https://github.com/rust-lang/rust/issues/84970> for more information

thread 'rustc' panicked at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/compiler/rustc_query_system/src/query/plumbing.rs:725:9:
Found unstable fingerprints for evaluate_obligation(4270e020b571106c-835a5b1013d879df): Ok(EvaluatedToAmbig)
stack backtrace:
   0:     0x7c40fa03c035 - std::backtrace_rs::backtrace::libunwind::trace::h1a07e5dba0da0cd2
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7c40fa03c035 - std::backtrace_rs::backtrace::trace_unsynchronized::h61b9b8394328c0bc
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7c40fa03c035 - std::sys_common::backtrace::_print_fmt::h1c5e18b460934cff
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7c40fa03c035 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h1e1a1972118942ad
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7c40fa08b29b - core::fmt::rt::Argument::fmt::h07af2b4071d536cd
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/core/src/fmt/rt.rs:165:63
   5:     0x7c40fa08b29b - core::fmt::write::hc090a2ffd6b28c4a
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/core/src/fmt/mod.rs:1157:21
   6:     0x7c40fa030bdf - std::io::Write::write_fmt::h8898bac6ff039a23
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/io/mod.rs:1832:15
   7:     0x7c40fa03be0e - std::sys_common::backtrace::_print::h4e80c5803d4ee35b
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7c40fa03be0e - std::sys_common::backtrace::print::ha96650907276675e
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7c40fa03e779 - std::panicking::default_hook::{{closure}}::h215c2a0a8346e0e0
  10:     0x7c40fa03e4bd - std::panicking::default_hook::h207342be97478370
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/panicking.rs:298:9
  11:     0x7c40f6c891b7 - std[3c8ba8ebcf555201]::panicking::update_hook::<alloc[bfbae7e348dce413]::boxed::Box<rustc_driver_impl[c88438ade88661f4]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7c40fa03ee76 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::ha9c3bc81d312fd83
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/alloc/src/boxed.rs:2036:9
  13:     0x7c40fa03ee76 - std::panicking::rust_panic_with_hook::hac8bdceee1e4fe2c
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/panicking.rs:799:13
  14:     0x7c40fa03ec24 - std::panicking::begin_panic_handler::{{closure}}::h00d785e82757ce3c
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/panicking.rs:664:13
  15:     0x7c40fa03c4f9 - std::sys_common::backtrace::__rust_end_short_backtrace::h1628d957bcd06996
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7c40fa03e957 - rust_begin_unwind
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/panicking.rs:652:5
  17:     0x7c40fa087763 - core::panicking::panic_fmt::hdc63834ffaaefae5
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/core/src/panicking.rs:72:14
  18:     0x7c40f74067a6 - rustc_query_system[4e189ce2c77124d]::query::plumbing::incremental_verify_ich_failed::<rustc_middle[3ff731b746e7b038]::ty::context::TyCtxt>
  19:     0x7c40f8553e58 - rustc_query_system[4e189ce2c77124d]::query::plumbing::try_execute_query::<rustc_query_impl[a12402620de91e8]::DynamicConfig<rustc_query_system[4e189ce2c77124d]::query::caches::DefaultCache<rustc_type_ir[a145be3c51398263]::canonical::Canonical<rustc_middle[3ff731b746e7b038]::ty::context::TyCtxt, rustc_middle[3ff731b746e7b038]::ty::ParamEnvAnd<rustc_middle[3ff731b746e7b038]::ty::predicate::Predicate>>, rustc_middle[3ff731b746e7b038]::query::erase::Erased<[u8; 2usize]>>, false, false, false>, rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt, true>
  20:     0x7c40f85525e0 - rustc_query_impl[a12402620de91e8]::query_impl::evaluate_obligation::get_query_incr::__rust_end_short_backtrace
  21:     0x7c40f4d7b644 - <rustc_trait_selection[173dcaf5d960508e]::traits::fulfill::FulfillProcessor as rustc_data_structures[52ff41d7b92c45f3]::obligation_forest::ObligationProcessor>::process_obligation
  22:     0x7c40f800ea00 - <rustc_data_structures[52ff41d7b92c45f3]::obligation_forest::ObligationForest<rustc_trait_selection[173dcaf5d960508e]::traits::fulfill::PendingPredicateObligation>>::process_obligations::<rustc_trait_selection[173dcaf5d960508e]::traits::fulfill::FulfillProcessor>
  23:     0x7c40f4ea3cff - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_method_argument_types
  24:     0x7c40f8abc1d5 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  25:     0x7c40f8aba6a4 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  26:     0x7c40f8ab4aec - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_block_with_expected
  27:     0x7c40f8aba64d - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  28:     0x7c40f8abe662 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  29:     0x7c40f8ab5bb6 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_block_with_expected
  30:     0x7c40f8ac06a5 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  31:     0x7c40f8abe662 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  32:     0x7c40f8abd580 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  33:     0x7c40f8ab5bb6 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_block_with_expected
  34:     0x7c40f8aba64d - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  35:     0x7c40f8ab4bc6 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_block_with_expected
  36:     0x7c40f8aba64d - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  37:     0x7c40f84ddc8c - rustc_hir_typeck[e95414a4bbf7473d]::check::check_fn
  38:     0x7c40f8746b96 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_closure
  39:     0x7c40f8abfc0a - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  40:     0x7c40f8482980 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_decl
  41:     0x7c40f8ab5c4c - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_block_with_expected
  42:     0x7c40f8aba64d - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  43:     0x7c40f8abd580 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  44:     0x7c40f8ab4bc6 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_block_with_expected
  45:     0x7c40f8aba64d - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  46:     0x7c40f84ddc8c - rustc_hir_typeck[e95414a4bbf7473d]::check::check_fn
  47:     0x7c40f8746b96 - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_closure
  48:     0x7c40f8abfc0a - <rustc_hir_typeck[e95414a4bbf7473d]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  49:     0x7c40f84ddc8c - rustc_hir_typeck[e95414a4bbf7473d]::check::check_fn
  50:     0x7c40f84d2baf - rustc_hir_typeck[e95414a4bbf7473d]::typeck
  51:     0x7c40f84d188d - rustc_query_impl[a12402620de91e8]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a12402620de91e8]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3ff731b746e7b038]::query::erase::Erased<[u8; 8usize]>>
  52:     0x7c40f81182b8 - rustc_query_system[4e189ce2c77124d]::query::plumbing::try_execute_query::<rustc_query_impl[a12402620de91e8]::DynamicConfig<rustc_query_system[4e189ce2c77124d]::query::caches::VecCache<rustc_span[8c7415e9d33ddd75]::def_id::LocalDefId, rustc_middle[3ff731b746e7b038]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt, true>
  53:     0x7c40f8116dd8 - rustc_query_impl[a12402620de91e8]::plumbing::force_from_dep_node::<rustc_query_impl[a12402620de91e8]::DynamicConfig<rustc_query_system[4e189ce2c77124d]::query::caches::VecCache<rustc_span[8c7415e9d33ddd75]::def_id::LocalDefId, rustc_middle[3ff731b746e7b038]::query::erase::Erased<[u8; 8usize]>>, false, false, false>>
  54:     0x7c40f8ee0ced - <rustc_query_impl[a12402620de91e8]::plumbing::query_callback<rustc_query_impl[a12402620de91e8]::query_impl::typeck::QueryType>::{closure#0} as core[868bc93c3f2beb33]::ops::function::FnOnce<(rustc_middle[3ff731b746e7b038]::ty::context::TyCtxt, rustc_query_system[4e189ce2c77124d]::dep_graph::dep_node::DepNode)>>::call_once
  55:     0x7c40f80299df - <rustc_query_system[4e189ce2c77124d]::dep_graph::graph::DepGraphData<rustc_middle[3ff731b746e7b038]::dep_graph::DepsType>>::try_mark_previous_green::<rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt>
  56:     0x7c40f802994b - <rustc_query_system[4e189ce2c77124d]::dep_graph::graph::DepGraphData<rustc_middle[3ff731b746e7b038]::dep_graph::DepsType>>::try_mark_previous_green::<rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt>
  57:     0x7c40f802994b - <rustc_query_system[4e189ce2c77124d]::dep_graph::graph::DepGraphData<rustc_middle[3ff731b746e7b038]::dep_graph::DepsType>>::try_mark_previous_green::<rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt>
  58:     0x7c40f802994b - <rustc_query_system[4e189ce2c77124d]::dep_graph::graph::DepGraphData<rustc_middle[3ff731b746e7b038]::dep_graph::DepsType>>::try_mark_previous_green::<rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt>
  59:     0x7c40f80291c4 - <rustc_query_system[4e189ce2c77124d]::dep_graph::graph::DepGraphData<rustc_middle[3ff731b746e7b038]::dep_graph::DepsType>>::try_mark_green::<rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt>
  60:     0x7c40f89821f7 - rustc_query_system[4e189ce2c77124d]::query::plumbing::ensure_must_run::<rustc_query_impl[a12402620de91e8]::DynamicConfig<rustc_query_system[4e189ce2c77124d]::query::caches::DefaultCache<rustc_span[8c7415e9d33ddd75]::def_id::LocalModDefId, rustc_middle[3ff731b746e7b038]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt>
  61:     0x7c40f8982716 - rustc_query_impl[a12402620de91e8]::query_impl::check_mod_type_wf::get_query_incr::__rust_end_short_backtrace
  62:     0x7c40f87ca1d0 - rustc_hir_analysis[46a17d8846b4335f]::check_crate
  63:     0x7c40f89890e0 - rustc_interface[640972162e3c086f]::passes::analysis
  64:     0x7c40f8988aef - rustc_query_impl[a12402620de91e8]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a12402620de91e8]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3ff731b746e7b038]::query::erase::Erased<[u8; 1usize]>>
  65:     0x7c40f8e71e53 - rustc_query_system[4e189ce2c77124d]::query::plumbing::try_execute_query::<rustc_query_impl[a12402620de91e8]::DynamicConfig<rustc_query_system[4e189ce2c77124d]::query::caches::SingleCache<rustc_middle[3ff731b746e7b038]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[a12402620de91e8]::plumbing::QueryCtxt, true>
  66:     0x7c40f8e71a9c - rustc_query_impl[a12402620de91e8]::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
  67:     0x7c40f8b83149 - rustc_interface[640972162e3c086f]::interface::run_compiler::<core[868bc93c3f2beb33]::result::Result<(), rustc_span[8c7415e9d33ddd75]::ErrorGuaranteed>, rustc_driver_impl[c88438ade88661f4]::run_compiler::{closure#0}>::{closure#1}
  68:     0x7c40f8b40f8b - std[3c8ba8ebcf555201]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[640972162e3c086f]::util::run_in_thread_with_globals<rustc_interface[640972162e3c086f]::interface::run_compiler<core[868bc93c3f2beb33]::result::Result<(), rustc_span[8c7415e9d33ddd75]::ErrorGuaranteed>, rustc_driver_impl[c88438ade88661f4]::run_compiler::{closure#0}>::{closure#1}, core[868bc93c3f2beb33]::result::Result<(), rustc_span[8c7415e9d33ddd75]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[868bc93c3f2beb33]::result::Result<(), rustc_span[8c7415e9d33ddd75]::ErrorGuaranteed>>
  69:     0x7c40f8b40d80 - <<std[3c8ba8ebcf555201]::thread::Builder>::spawn_unchecked_<rustc_interface[640972162e3c086f]::util::run_in_thread_with_globals<rustc_interface[640972162e3c086f]::interface::run_compiler<core[868bc93c3f2beb33]::result::Result<(), rustc_span[8c7415e9d33ddd75]::ErrorGuaranteed>, rustc_driver_impl[c88438ade88661f4]::run_compiler::{closure#0}>::{closure#1}, core[868bc93c3f2beb33]::result::Result<(), rustc_span[8c7415e9d33ddd75]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[868bc93c3f2beb33]::result::Result<(), rustc_span[8c7415e9d33ddd75]::ErrorGuaranteed>>::{closure#2} as core[868bc93c3f2beb33]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  70:     0x7c40fa048cab - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h09e5a4c541afa800
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/alloc/src/boxed.rs:2022:9
  71:     0x7c40fa048cab - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h9c8b03c22f4e7026
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/alloc/src/boxed.rs:2022:9
  72:     0x7c40fa048cab - std::sys::pal::unix::thread::Thread::new::thread_start::h522bc89a54da820a
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/sys/pal/unix/thread.rs:108:17
  73:     0x7c40f3ca6ded - <unknown>
  74:     0x7c40f3d2a0dc - <unknown>
  75:                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: rustc 1.79.0 (129f3b996 2024-06-10) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED]

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [evaluate_obligation] evaluating trait selection obligation `&'a str: core::marker::Send`
#1 [typeck] type-checking `dht_service::<impl at src/dht_service.rs:179:1: 179:11>::bootstrap_with_random_id`
#2 [analysis] running analysis passes on this crate
end of query stack
there was a panic while trying to force a dep node
try_mark_green dep node stack:
#0 type_of_opaque(midwest_mainline[083c]::dht_service::{impl#7}::bootstrap_with_random_id::{opaque#0})
#1 type_of(midwest_mainline[083c]::dht_service::{impl#7}::bootstrap_with_random_id::{opaque#0})
#2 check_well_formed(midwest_mainline[083c]::dht_service::{impl#7}::bootstrap_with_random_id::{opaque#0})
#3 check_mod_type_wf(midwest_mainline[083c]::dht_service)
end of try_mark_green dep node stack

```

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<details><summary><strong>Backtrace</strong></summary>
<p>

```
<backtrace>
```

</p>
</details>

### Other info
I was using unstable feature of tokio and this was my `.cargo/config.toml`

Note the comments are intentional. I already commented out the lines about mold a few days ago before I hit the ICE so may or may not be related.
```toml
[build]
rustflags = ["--cfg", "tokio_unstable"]

# [target.x86_64-unknown-linux-gnu]
# linker = "clang"
# rustflags = ["-C", "link-arg=-fuse-ld=/usr/bin/mold"]
```