thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value'

[Systemcluster]

This issue appears in the nightly compiler since toolchain version nightly-2020-08-14 (rustc 1.47.0-nightly (81dc88f88 2020-08-13)). It does not appear with toolchain nightly-2020-08-13 (rustc 1.47.0-nightly (576d27c5a 2020-08-12)) or earlier.

Code

Create an empty project and add the following dependency.

[dependencies]
naga = {git = "https://github.com/gfx-rs/naga", rev = "1eb637038dd15fc1dad770eca8e6943424dbc122"}

Upon cargo run, rustc panics with the below output.

Meta

rustc --version --verbose:

rustc 1.47.0-nightly (8e21bd063 2020-08-14)
binary: rustc
commit-hash: 8e21bd0633b8d970646ee6eb706c9e8acfad19af
commit-date: 2020-08-14
host: x86_64-pc-windows-msvc
release: 1.47.0-nightly
LLVM version: 10.0

Error output

Compiling naga v0.1.0 (https://github.com/gfx-rs/naga?rev=1eb637038dd15fc1dad770eca8e6943424dbc122#1eb63703)
     Running `rustc --crate-name naga --edition=2018 C:\Users\Chris\.cargo\git\checkouts\naga-dbb2b19faed49210\1eb6370\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -Cembed-bitcode=no -C debuginfo=2 --cfg "feature=\"default\"" -C metadata=b78cb55e6bbf7f02 -C extra-filename=-b78cb55e6bbf7f02 --out-dir C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps -L dependency=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps --extern bitflags=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libbitflags-b3aa381b8c8a158c.rmeta --extern fxhash=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libfxhash-abd942eca949d6c8.rmeta --extern log=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\liblog-5edde9ce5ee6a1cc.rmeta --extern num_traits=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libnum_traits-55b459a906b3f58a.rmeta --extern thiserror=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libthiserror-cd69ea1eee32f495.rmeta --cap-lints allow`
thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', src\librustc_mir\transform\match_branches.rs:54:81
stack backtrace:
   0:     0x7fff5d918ff9 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hfae6a97726d8b736
   1:     0x7fff5d94599c - core::fmt::write::hce2ddfec834877b8
   2:     0x7fff5d90ad9c - <std::io::IoSlice as core::fmt::Debug>::fmt::h57a15d9f0ff2a3bc
   3:     0x7fff5d91e5cb - std::panicking::take_hook::h1925373a96008b93
   4:     0x7fff5d91e218 - std::panicking::take_hook::h1925373a96008b93
   5:     0x7fff246954fa - rustc_driver::report_ice::h91547ccde81af24e
   6:     0x7fff5d91ef70 - std::panicking::rust_panic_with_hook::h7f7de81d557f54d3
   7:     0x7fff5d91eaa5 - rust_begin_unwind
   8:     0x7fff5d9198af - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hfae6a97726d8b736
   9:     0x7fff5d91ea59 - rust_begin_unwind
  10:     0x7fff5d9422e0 - core::panicking::panic_fmt::h599cc82b32e741b9
  11:     0x7fff5d94222c - core::panicking::panic::h4d7ada597da16bd9
  12:     0x7fff27526e42 - <rustc_mir::transform::match_branches::MatchBranchSimplification as rustc_mir::transform::MirPass>::run_pass::hb91e63ab8948ed14
  13:     0x7fff2766e0d9 - rustc_mir::transform::run_passes::hc006433f70a0d186
  14:     0x7fff27670942 - rustc_mir::transform::run_passes::hc006433f70a0d186
  15:     0x7fff27670eac - rustc_mir::transform::run_passes::hc006433f70a0d186
  16:     0x7fff27670bf3 - rustc_mir::transform::run_passes::hc006433f70a0d186
  17:     0x7fff2855369d - rustc_feature::UnstableFeatures::is_nightly_build::hf20f74c3bb454638
  18:     0x7fff286135e9 - ZN12rustc_middle2ty5print6pretty66_DERIVE_rustc_middle_ty_Lift_lifted_FOR_TraitRefPrintOnlyTraitPath121_$LT$impl$u20$rustc_middle..ty..context..Lift$u20$for$u20$rustc_middle..ty..print..pretty..TraitRefPrintOnlyTraitPath$GT$11lift_to_tcx17h98c3c4fb98b9687
  19:     0x7fff28419e29 - rustc_feature::UnstableFeatures::is_nightly_build::hf20f74c3bb454638
  20:     0x7fff28709dbb - rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::instance_mir::h76dbaaa3af662a3c
  21:     0x7fff27443394 - <rustc_mir::monomorphize::collector::RootCollector as rustc_hir::itemlikevisit::ItemLikeVisitor>::visit_impl_item::h5cd1c489b5156be3
  22:     0x7fff2743df69 - rustc_mir::monomorphize::collector::collect_crate_mono_items::h353c8d9ad96cacce
  23:     0x7fff275546d6 - <rustc_mir::dataflow::impls::borrows::BorrowIndex as core::fmt::Debug>::fmt::h983c54cf04b64bf1
  24:     0x7fff2743c7ac - rustc_mir::monomorphize::collector::collect_crate_mono_items::h353c8d9ad96cacce
  25:     0x7fff27707ef0 - rustc_mir::monomorphize::partitioning::compute_codegen_unit_name::h5212d0f143645fd4
  26:     0x7fff27854537 - <rustc_codegen_ssa::meth::VirtualIndex as core::fmt::Debug>::fmt::he98a319022b78233
  27:     0x7fff278324f3 - <rustc_codegen_ssa::mir::block::<impl rustc_codegen_ssa::mir::FunctionCx<Bx>>::codegen_panic_intrinsic::AssertIntrinsic as core::fmt::Debug>::fmt::hf03f9321433764a5
  28:     0x7fff277d77d0 - <rustc_codegen_ssa::coverageinfo::map::ExpressionRegion as core::fmt::Debug>::fmt::h6ac1c379b5cb3970
  29:     0x7fff278145b3 - <rustc_codegen_ssa::mir::block::<impl rustc_codegen_ssa::mir::FunctionCx<Bx>>::codegen_panic_intrinsic::AssertIntrinsic as core::fmt::Debug>::fmt::hf03f9321433764a5
  30:     0x7fff278613c1 - rustc_codegen_ssa::back::symbol_export::crates_export_threshold::h701789d39c12c5bb
  31:     0x7fff27a0a88e - rustc_plugin_impl::build::provide::h31aa2c45a0b2beac
  32:     0x7fff27bd213e - ZN14rustc_metadata5rmeta7decoder17__ty_decoder_impl186_$LT$impl$u20$rustc_serialize..serialize..SpecializedDecoder$LT$$RF$rustc_middle..mir..interpret..allocation..Allocation$GT$$u20$for$u20$rustc_metadata..rmeta..decoder..DecodeContext$GT$18specialized_d
  33:     0x7fff27be1b10 - ZN14rustc_metadata5rmeta7decoder17__ty_decoder_impl186_$LT$impl$u20$rustc_serialize..serialize..SpecializedDecoder$LT$$RF$rustc_middle..mir..interpret..allocation..Allocation$GT$$u20$for$u20$rustc_metadata..rmeta..decoder..DecodeContext$GT$18specialized_d
  34:     0x7fff27b42987 - <u32 as rustc_metadata::rmeta::table::FixedSizeEncoding>::write_to_bytes_at::ha75ed890010d59b5
  35:     0x7fff27a1d0c6 - <rustc_metadata::rmeta::encoder::EncodeContext as rustc_serialize::serialize::SpecializedEncoder<rustc_data_structures::fingerprint::Fingerprint>>::specialized_encode::h27f2383a265888ea
  36:     0x7fff27a2c9b2 - <rustc_metadata::rmeta::encoder::PrefetchVisitor as rustc_hir::itemlikevisit::ParItemLikeVisitor>::visit_impl_item::h41f95b5bba7b4361
  37:     0x7fff27acc6cd - rustc_metadata::dynamic_lib::DynamicLibrary::open::hd9e07ef0fa8b5dfe
  38:     0x7fff27bf3e62 - rustc_metadata::rmeta::decoder::cstore_impl::<impl rustc_middle::middle::cstore::CrateStore for rustc_metadata::creader::CStore>::encode_metadata::h5b49c2aa9357f24e
  39:     0x7fff28702bce - rustc_middle::ty::context::TyCtxt::encode_metadata::he08193cbd631d4ff
  40:     0x7fff24a348bf - rustc_interface::passes::BoxedResolver::to_resolver_outputs::h1d6186a99825b11e
  41:     0x7fff24961176 - rustc_interface::queries::Queries::ongoing_codegen::h43c89a54be4efc35
  42:     0x7fff246d40e3 - <rustc_infer::infer::canonical::canonicalizer::Canonicalizer as rustc_middle::ty::fold::TypeFolder>::tcx::h4ddcddb18f09f250
  43:     0x7fff2469aa7c - <rustc_driver::DEFAULT_HOOK as core::ops::deref::Deref>::deref::h75f1e721d5dee9b1
  44:     0x7fff246d609c - <rustc_infer::infer::canonical::canonicalizer::Canonicalizer as rustc_middle::ty::fold::TypeFolder>::tcx::h4ddcddb18f09f250
  45:     0x7fff246c1fb0 - <regex::sparse::SparseSet as core::ops::deref::Deref>::deref::hcab2bfd369f1a834
  46:     0x7fff246c4989 - <regex::sparse::SparseSet as core::ops::deref::Deref>::deref::hcab2bfd369f1a834
  47:     0x7fff24679953 - <aho_corasick::prefilter::RareByteOffset as core::default::Default>::default::hd78c1f669c18c07d
  48:     0x7fff5d92ee4a - std::sys::windows::thread::Thread::new::h84550e08827b3a3a
  49:     0x7fffdb216fd4 - BaseThreadInitThunk
  50:     0x7fffdccbcec1 - RtlUserThreadStart

error: internal compiler error: unexpected panic

note: 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 1.47.0-nightly (8e21bd063 2020-08-14) running on x86_64-pc-windows-msvc

note: compiler flags: -C embed-bitcode=no -C debuginfo=2 --crate-type lib

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

query stack during panic:
#0 [optimized_mir] optimizing MIR for `proc::validator::Validator::validate`
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items
#2 [exported_symbols] exported_symbols
end of query stack
error: could not compile `naga`.

Caused by:
  process didn't exit successfully: `rustc --crate-name naga --edition=2018 C:\Users\Chris\.cargo\git\checkouts\naga-dbb2b19faed49210\1eb6370\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -Cembed-bitcode=no -C debuginfo=2 --cfg "feature=\"default\"" -C metadata=b78cb55e6bbf7f02 -C extra-filename=-b78cb55e6bbf7f02 --out-dir C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps -L dependency=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps --extern bitflags=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libbitflags-b3aa381b8c8a158c.rmeta --extern fxhash=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libfxhash-abd942eca949d6c8.rmeta --extern log=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\liblog-5edde9ce5ee6a1cc.rmeta --extern num_traits=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libnum_traits-55b459a906b3f58a.rmeta --extern thiserror=C:\Users\Chris\Development\ice-test-2020-08-15\target\debug\deps\libthiserror-cd69ea1eee32f495.rmeta --cap-lints allow` (exit code: 101)

[JulianKnodt]

Copying this over from the other duplicate issue:

• should be fixed by MatchBranchSimplification: fix equal const bool assignments #75537

[JulianKnodt]

I've just checked a crate which depends on naga on the latest nightly, and it no longer errors here.

rustc 1.47.0-nightly (9b88e0a86 2020-08-15)

[Systemcluster]

I can confirm it working now with the most recent nightly.