Failing to compile on nightly under branch coverage

[jayvdb]

Under both v2 and v1.13.2 branches the following occurs on the latest nightly.
It was working 24 hrs ago.
This is likely a problem that needs to be upstream in rustc as noted, but capturing it here also as other users of this crate are likely going to be seeing this.

rust-smallvec> cargo +nightly llvm-cov --branch test --all-features
warning: --branch option is unstable
info: cargo-llvm-cov currently setting cfg(coverage) and cfg(coverage_nightly); you can opt-out it by passing --no-cfg-coverage and --no-cfg-coverage-nightly
   Compiling serde v1.0.217
   Compiling bincode v1.3.3
   Compiling smallvec v2.0.0-alpha.9 (/home/jayvdb/rust/rust-smallvec)
error: internal compiler error: compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:168:90: Failed to normalize Alias(Projection, AliasTy { args: [A/#1, '{erased}], def_id: DefId(0:1610 ~ serde[72bd]::de::SeqAccess::Error), .. }), maybe try to call `try_normalize_erasing_regions` instead


thread 'rustc' panicked at compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:168:90:
Box<dyn Any>
stack backtrace:
   0:     0x7f69d9ae3a7a - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hc48a3003e72a1fb5
   1:     0x7f69da213126 - core::fmt::write::h244b471aa97315bd
   2:     0x7f69db122211 - std::io::Write::write_fmt::h63cacec38f2c7922
   3:     0x7f69d9ae38d2 - std::sys::backtrace::BacktraceLock::print::h8e88b30882062ce8
   4:     0x7f69d9ae5e77 - std::panicking::default_hook::{{closure}}::he2b2f35b61e5b6b4
   5:     0x7f69d9ae5c60 - std::panicking::default_hook::h2b9fc43053d2ca15
   6:     0x7f69d8c568a8 - std[c08ade969ea4a026]::panicking::update_hook::<alloc[ecf666bc700c7d64]::boxed::Box<rustc_driver_impl[7ccddf7307cff907]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x7f69d9ae66c3 - std::panicking::rust_panic_with_hook::h1126dbe971a7f919
   8:     0x7f69d8c8ecc1 - std[c08ade969ea4a026]::panicking::begin_panic::<rustc_errors[1eaa06d4a73dafc5]::ExplicitBug>::{closure#0}
   9:     0x7f69d8c83ea6 - std[c08ade969ea4a026]::sys::backtrace::__rust_end_short_backtrace::<std[c08ade969ea4a026]::panicking::begin_panic<rustc_errors[1eaa06d4a73dafc5]::ExplicitBug>::{closure#0}, !>
  10:     0x7f69d8c83c63 - std[c08ade969ea4a026]::panicking::begin_panic::<rustc_errors[1eaa06d4a73dafc5]::ExplicitBug>
  11:     0x7f69d8c98c21 - <rustc_errors[1eaa06d4a73dafc5]::diagnostic::BugAbort as rustc_errors[1eaa06d4a73dafc5]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x7f69d926db03 - rustc_middle[bc4ae9fc2bf4235a]::util::bug::opt_span_bug_fmt::<rustc_span[cfc513d191a8d813]::span_encoding::Span>::{closure#0}
  13:     0x7f69d9252b1a - rustc_middle[bc4ae9fc2bf4235a]::ty::context::tls::with_opt::<rustc_middle[bc4ae9fc2bf4235a]::util::bug::opt_span_bug_fmt<rustc_span[cfc513d191a8d813]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  14:     0x7f69d92529ab - rustc_middle[bc4ae9fc2bf4235a]::ty::context::tls::with_context_opt::<rustc_middle[bc4ae9fc2bf4235a]::ty::context::tls::with_opt<rustc_middle[bc4ae9fc2bf4235a]::util::bug::opt_span_bug_fmt<rustc_span[cfc513d191a8d813]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  15:     0x7f69d73d3d20 - rustc_middle[bc4ae9fc2bf4235a]::util::bug::bug_fmt
  16:     0x7f69da80f12f - <rustc_middle[bc4ae9fc2bf4235a]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder as rustc_type_ir[72683c14ceefff53]::fold::TypeFolder<rustc_middle[bc4ae9fc2bf4235a]::ty::context::TyCtxt>>::fold_ty
  17:     0x7f69db48b513 - <&rustc_middle[bc4ae9fc2bf4235a]::ty::list::RawList<(), rustc_middle[bc4ae9fc2bf4235a]::ty::generic_args::GenericArg> as rustc_type_ir[72683c14ceefff53]::fold::TypeFoldable<rustc_middle[bc4ae9fc2bf4235a]::ty::context::TyCtxt>>::try_fold_with::<rustc_middle[bc4ae9fc2bf4235a]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder>
  18:     0x7f69d97afe45 - <rustc_middle[bc4ae9fc2bf4235a]::ty::context::TyCtxt>::normalize_erasing_regions::<rustc_type_ir[72683c14ceefff53]::predicate::TraitRef<rustc_middle[bc4ae9fc2bf4235a]::ty::context::TyCtxt>>
  19:     0x7f69d97bcb75 - <rustc_symbol_mangling[403ef980f7f2d81]::v0::SymbolMangler as rustc_middle[bc4ae9fc2bf4235a]::ty::print::Printer>::print_impl_path
  20:     0x7f69d97bc0b9 - <rustc_symbol_mangling[403ef980f7f2d81]::v0::SymbolMangler as rustc_middle[bc4ae9fc2bf4235a]::ty::print::Printer>::print_def_path
  21:     0x7f69d97bc7a5 - <rustc_symbol_mangling[403ef980f7f2d81]::v0::SymbolMangler as rustc_middle[bc4ae9fc2bf4235a]::ty::print::Printer>::print_def_path
  22:     0x7f69d97bbbd0 - rustc_symbol_mangling[403ef980f7f2d81]::v0::mangle
  23:     0x7f69dad226ae - rustc_symbol_mangling[403ef980f7f2d81]::symbol_name_provider
  24:     0x7f69dad2112a - rustc_query_impl[9bbd9b92042adb73]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[9bbd9b92042adb73]::query_impl::symbol_name::dynamic_query::{closure#2}::{closure#0}, rustc_middle[bc4ae9fc2bf4235a]::query::erase::Erased<[u8; 16usize]>>
  25:     0x7f69dad200b7 - rustc_query_system[7c1448542a492b7f]::query::plumbing::try_execute_query::<rustc_query_impl[9bbd9b92042adb73]::DynamicConfig<rustc_query_system[7c1448542a492b7f]::query::caches::DefaultCache<rustc_middle[bc4ae9fc2bf4235a]::ty::instance::Instance, rustc_middle[bc4ae9fc2bf4235a]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[9bbd9b92042adb73]::plumbing::QueryCtxt, false>
  26:     0x7f69dad1fd22 - rustc_query_impl[9bbd9b92042adb73]::query_impl::symbol_name::get_query_non_incr::__rust_end_short_backtrace
  27:     0x7f69dada968c - rustc_middle[bc4ae9fc2bf4235a]::query::plumbing::query_get_at::<rustc_query_system[7c1448542a492b7f]::query::caches::DefaultCache<rustc_middle[bc4ae9fc2bf4235a]::ty::instance::Instance, rustc_middle[bc4ae9fc2bf4235a]::query::erase::Erased<[u8; 16usize]>>>
  28:     0x7f69d8add915 - rustc_codegen_llvm[cf0745383bf2fa70]::coverageinfo::mapgen::finalize
  29:     0x7f69dad3e458 - rustc_codegen_llvm[cf0745383bf2fa70]::base::compile_codegen_unit::module_codegen
  30:     0x7f69db1e9dc8 - <rustc_codegen_llvm[cf0745383bf2fa70]::LlvmCodegenBackend as rustc_codegen_ssa[8aad7319a10dd306]::traits::backend::ExtraBackendMethods>::compile_codegen_unit
  31:     0x7f69db1e612c - <rustc_codegen_llvm[cf0745383bf2fa70]::LlvmCodegenBackend as rustc_codegen_ssa[8aad7319a10dd306]::traits::backend::CodegenBackend>::codegen_crate
  32:     0x7f69db1ee124 - <rustc_interface[9ea0a400d5371a28]::queries::Linker>::codegen_and_build_linker
  33:     0x7f69db158892 - rustc_interface[9ea0a400d5371a28]::passes::create_and_enter_global_ctxt::<core[6b5cbebef9c0da3b]::option::Option<rustc_interface[9ea0a400d5371a28]::queries::Linker>, rustc_driver_impl[7ccddf7307cff907]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  34:     0x7f69db1cba64 - rustc_interface[9ea0a400d5371a28]::interface::run_compiler::<(), rustc_driver_impl[7ccddf7307cff907]::run_compiler::{closure#0}>::{closure#1}
  35:     0x7f69db02d651 - std[c08ade969ea4a026]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[9ea0a400d5371a28]::util::run_in_thread_with_globals<rustc_interface[9ea0a400d5371a28]::util::run_in_thread_pool_with_globals<rustc_interface[9ea0a400d5371a28]::interface::run_compiler<(), rustc_driver_impl[7ccddf7307cff907]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  36:     0x7f69db02db08 - <<std[c08ade969ea4a026]::thread::Builder>::spawn_unchecked_<rustc_interface[9ea0a400d5371a28]::util::run_in_thread_with_globals<rustc_interface[9ea0a400d5371a28]::util::run_in_thread_pool_with_globals<rustc_interface[9ea0a400d5371a28]::interface::run_compiler<(), rustc_driver_impl[7ccddf7307cff907]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[6b5cbebef9c0da3b]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  37:     0x7f69db02f0af - std::sys::pal::unix::thread::Thread::new::thread_start::h2f2b51e924b57f78
  38:     0x7f69d52983b2 - start_thread
  39:     0x7f69d531d5fc - __clone3
  40:                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 make sure that you have updated to the latest nightly

note: please attach the file at `/home/jayvdb/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/serde-1.0.217/rustc-ice-2025-01-09T10_59_17-2792671.txt` to your bug report

note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2 -C instrument-coverage -Z coverage-options=branch

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [symbol_name] computing the symbol for `de::value::<impl at /home/jayvdb/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/serde-1.0.217/src/de/value.rs:1212:1: 1214:27>::into_deserializer`
end of query stack
error: could not compile `serde` (lib)

Caused by:
  process didn't exit successfully: `/home/jayvdb/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc --crate-name serde --edition=2018 /home/jayvdb/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/serde-1.0.217/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=190 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="std"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("alloc", "default", "derive", "rc", "serde_derive", "std", "unstable"))' -C metadata=0f48dfd3ac74974d -C extra-filename=-5a4c666c14890bf8 --out-dir /home/jayvdb/rust/rust-smallvec/target/llvm-cov-target/debug/deps -L dependency=/home/jayvdb/rust/rust-smallvec/target/llvm-cov-target/debug/deps --cap-lints allow -C instrument-coverage -Z coverage-options=branch --cfg=coverage --cfg=coverage_nightly --cfg=trybuild_no_target --check-cfg 'cfg(no_core_cstr)' --check-cfg 'cfg(no_core_error)' --check-cfg 'cfg(no_core_net)' --check-cfg 'cfg(no_core_num_saturating)' --check-cfg 'cfg(no_core_try_from)' --check-cfg 'cfg(no_diagnostic_namespace)' --check-cfg 'cfg(no_float_copysign)' --check-cfg 'cfg(no_num_nonzero_signed)' --check-cfg 'cfg(no_relaxed_trait_bounds)' --check-cfg 'cfg(no_serde_derive)' --check-cfg 'cfg(no_std_atomic)' --check-cfg 'cfg(no_std_atomic64)' --check-cfg 'cfg(no_systemtime_checked_add)' --check-cfg 'cfg(no_target_has_atomic)'` (exit status: 101)
warning: build failed, waiting for other jobs to finish...
error: process didn't exit successfully: `/home/jayvdb/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/cargo test --tests --manifest-path /home/jayvdb/rust/rust-smallvec/Cargo.toml --target-dir /home/jayvdb/rust/rust-smallvec/target/llvm-cov-target --all-features` (exit status: 101)

[jayvdb]

tracking issue upstream: rust-lang/rust#135235

[jayvdb]

Fixed in latest nightly.