ICE: Failed to normalize, maybe try to call `try_normalize_erasing_regions` instead

[12101111]

Code

I found this ICE while compiling bitvec 0.19.6 in release mode.

https://github.com/ferrilab/bitvec/tree/v0/19/6

Meta

rustc --version --verbose:

rustc 1.71.0-nightly (fec9adcdb 2023-04-21)
binary: rustc
commit-hash: fec9adcdbc21469ef105162cc8cabf81c72d06be
commit-date: 2023-04-21
host: aarch64-apple-darwin
release: 1.71.0-nightly
LLVM version: 16.0.2

Error output

error: internal compiler error: compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:195:90: Failed to normalize alloc::raw_vec::RawVec<<T as store::BitStore>::Mem>, maybe try to call `try_normalize_erasing_regions` instead

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/fec9adcdbc21469ef105162cc8cabf81c72d06be/compiler/rustc_errors/src/lib.rs:1643:9

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 1.71.0-nightly (fec9adcdb 2023-04-21) running on aarch64-apple-darwin

note: compiler flags: --crate-type lib -C opt-level=3 -C embed-bitcode=no -C target-cpu=apple-m1

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

query stack during panic:
#0 [mir_shims] generating MIR shim for `core::ptr::drop_in_place`
#1 [optimized_mir] optimizing MIR for `vec::ops::<impl at src/vec/ops.rs:141:1: 141:33>::drop::{closure#0}`
end of query stack

Backtrace

stack backtrace:
   0:        0x104a90738 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::ha9e6c436959f1b8e
   1:        0x104ae075c - core::fmt::write::h03620c265cda50c9
   2:        0x104a86658 - std::io::Write::write_fmt::h4582733544e760df
   3:        0x104a90598 - std::sys_common::backtrace::print::h52cbdd72190599ef
   4:        0x104a92f38 - std::panicking::default_hook::{{closure}}::hbd7990be14834316
   5:        0x104a92d3c - std::panicking::default_hook::hefa394ac64f6527f
   6:        0x10cfb5b58 - rustc_driver_impl[9431cfa2328e8da]::DEFAULT_HOOK::{closure#0}::{closure#0}
   7:        0x104a9352c - std::panicking::rust_panic_with_hook::h7504e9066f7b4f07
   8:        0x110d6c2e8 - std[614eb408c5fa570d]::panicking::begin_panic::<rustc_errors[c2a69e08fcd2e8bf]::ExplicitBug>::{closure#0}
   9:        0x110d69db0 - std[614eb408c5fa570d]::sys_common::backtrace::__rust_end_short_backtrace::<std[614eb408c5fa570d]::panicking::begin_panic<rustc_errors[c2a69e08fcd2e8bf]::ExplicitBug>::{closure#0}, !>
  10:        0x1113a1b44 - std[614eb408c5fa570d]::panicking::begin_panic::<rustc_errors[c2a69e08fcd2e8bf]::ExplicitBug>
  11:        0x110e2b5ac - <rustc_errors[c2a69e08fcd2e8bf]::HandlerInner>::bug::<&alloc[8ca104b1f3df9592]::string::String>
  12:        0x110e2b270 - <rustc_errors[c2a69e08fcd2e8bf]::Handler>::bug::<&alloc[8ca104b1f3df9592]::string::String>
  13:        0x110dd1124 - rustc_middle[662f54c0a25f7c56]::util::bug::opt_span_bug_fmt::<rustc_span[7733720cb78d73dd]::span_encoding::Span>::{closure#0}
  14:        0x110dd0b34 - rustc_middle[662f54c0a25f7c56]::ty::context::tls::with_opt::<rustc_middle[662f54c0a25f7c56]::util::bug::opt_span_bug_fmt<rustc_span[7733720cb78d73dd]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  15:        0x110dd0b00 - rustc_middle[662f54c0a25f7c56]::ty::context::tls::with_context_opt::<rustc_middle[662f54c0a25f7c56]::ty::context::tls::with_opt<rustc_middle[662f54c0a25f7c56]::util::bug::opt_span_bug_fmt<rustc_span[7733720cb78d73dd]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  16:        0x1113a18ac - rustc_middle[662f54c0a25f7c56]::util::bug::bug_fmt
  17:        0x110dcdea8 - <rustc_middle[662f54c0a25f7c56]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder>::normalize_generic_arg_after_erasing_regions
  18:        0x110dcdee4 - <rustc_middle[662f54c0a25f7c56]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder as rustc_type_ir[50bb8a969b2c53c]::fold::TypeFolder<rustc_middle[662f54c0a25f7c56]::ty::context::TyCtxt>>::fold_ty
  19:        0x10f6d33cc - <core[dc40836e4f3e0da7]::iter::adapters::map::Map<core[dc40836e4f3e0da7]::iter::adapters::enumerate::Enumerate<core[dc40836e4f3e0da7]::slice::iter::Iter<rustc_middle[662f54c0a25f7c56]::ty::FieldDef>>, <rustc_mir_dataflow[2ace872dcdcb608a]::elaborate_drops::DropCtxt<rustc_mir_transform[c661f0a31a836e75]::shim::DropShimElaborator>>::move_paths_for_fields::{closure#0}> as core[dc40836e4f3e0da7]::iter::traits::iterator::Iterator>::fold::<(), core[dc40836e4f3e0da7]::iter::traits::iterator::Iterator::for_each::call<(rustc_middle[662f54c0a25f7c56]::mir::syntax::Place, core[dc40836e4f3e0da7]::option::Option<()>), <alloc[8ca104b1f3df9592]::vec::Vec<(rustc_middle[662f54c0a25f7c56]::mir::syntax::Place, core[dc40836e4f3e0da7]::option::Option<()>)>>::extend_trusted<core[dc40836e4f3e0da7]::iter::adapters::map::Map<core[dc40836e4f3e0da7]::iter::adapters::enumerate::Enumerate<core[dc40836e4f3e0da7]::slice::iter::Iter<rustc_middle[662f54c0a25f7c56]::ty::FieldDef>>, <rustc_mir_dataflow[2ace872dcdcb608a]::elaborate_drops::DropCtxt<rustc_mir_transform[c661f0a31a836e75]::shim::DropShimElaborator>>::move_paths_for_fields::{closure#0}>>::{closure#0}>::{closure#0}>
  20:        0x10f7e0f04 - <alloc[8ca104b1f3df9592]::vec::Vec<(rustc_middle[662f54c0a25f7c56]::mir::syntax::Place, core[dc40836e4f3e0da7]::option::Option<()>)> as alloc[8ca104b1f3df9592]::vec::spec_from_iter::SpecFromIter<(rustc_middle[662f54c0a25f7c56]::mir::syntax::Place, core[dc40836e4f3e0da7]::option::Option<()>), core[dc40836e4f3e0da7]::iter::adapters::map::Map<core[dc40836e4f3e0da7]::iter::adapters::enumerate::Enumerate<core[dc40836e4f3e0da7]::slice::iter::Iter<rustc_middle[662f54c0a25f7c56]::ty::FieldDef>>, <rustc_mir_dataflow[2ace872dcdcb608a]::elaborate_drops::DropCtxt<rustc_mir_transform[c661f0a31a836e75]::shim::DropShimElaborator>>::move_paths_for_fields::{closure#0}>>>::from_iter
  21:        0x10f6de998 - <rustc_mir_dataflow[2ace872dcdcb608a]::elaborate_drops::DropCtxt<rustc_mir_transform[c661f0a31a836e75]::shim::DropShimElaborator>>::open_drop_for_adt
  22:        0x10f6de2e8 - <rustc_mir_dataflow[2ace872dcdcb608a]::elaborate_drops::DropCtxt<rustc_mir_transform[c661f0a31a836e75]::shim::DropShimElaborator>>::elaborate_drop
  23:        0x10f800090 - rustc_mir_transform[c661f0a31a836e75]::shim::make_shim
  24:        0x11027591c - <std[614eb408c5fa570d]::thread::local::LocalKey<core[dc40836e4f3e0da7]::cell::Cell<*const ()>>>::with::<rustc_middle[662f54c0a25f7c56]::ty::context::tls::enter_context<rustc_query_system[2ed44d2bc999b7a]::query::plumbing::execute_job_non_incr<rustc_query_impl[eba986b151bf483e]::queries::mir_shims, rustc_query_impl[eba986b151bf483e]::plumbing::QueryCtxt>::{closure#0}, rustc_middle[662f54c0a25f7c56]::query::erase::Erased<[u8; 8usize]>>::{closure#0}, rustc_middle[662f54c0a25f7c56]::query::erase::Erased<[u8; 8usize]>>
  25:        0x11014ccd0 - rustc_query_system[2ed44d2bc999b7a]::query::plumbing::try_execute_query::<rustc_query_impl[eba986b151bf483e]::queries::mir_shims, rustc_query_impl[eba986b151bf483e]::plumbing::QueryCtxt>
  26:        0x110347614 - <rustc_query_impl[eba986b151bf483e]::Queries as rustc_middle[662f54c0a25f7c56]::ty::query::QueryEngine>::mir_shims
  27:        0x110eba434 - <rustc_middle[662f54c0a25f7c56]::ty::context::TyCtxt>::instance_mir
  28:        0x10f7cb2c4 - <rustc_mir_transform[c661f0a31a836e75]::inline::Inliner>::try_inlining
  29:        0x10f7cac2c - <rustc_mir_transform[c661f0a31a836e75]::inline::Inliner>::process_blocks
  30:        0x10f7cad14 - <rustc_mir_transform[c661f0a31a836e75]::inline::Inliner>::process_blocks
  31:        0x10f7ca6f0 - <rustc_mir_transform[c661f0a31a836e75]::inline::Inline as rustc_middle[662f54c0a25f7c56]::mir::MirPass>::run_pass
  32:        0x10f7c3dd0 - rustc_mir_transform[c661f0a31a836e75]::pass_manager::run_passes_inner
  33:        0x10f6f15a8 - rustc_mir_transform[c661f0a31a836e75]::optimized_mir
  34:        0x1100dd060 - rustc_query_system[2ed44d2bc999b7a]::query::plumbing::try_execute_query::<rustc_query_impl[eba986b151bf483e]::queries::optimized_mir, rustc_query_impl[eba986b151bf483e]::plumbing::QueryCtxt>
  35:        0x11033e7b8 - <rustc_query_impl[eba986b151bf483e]::Queries as rustc_middle[662f54c0a25f7c56]::ty::query::QueryEngine>::optimized_mir
  36:        0x1106e1654 - <rustc_metadata[f2a84a8141f6c436]::rmeta::encoder::EncodeContext>::encode_crate_root
  37:        0x1106eeb08 - rustc_metadata[f2a84a8141f6c436]::rmeta::encoder::encode_metadata_impl
  38:        0x110695d88 - rustc_data_structures[240cd432e77d6b7b]::sync::join::<rustc_metadata[f2a84a8141f6c436]::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata[f2a84a8141f6c436]::rmeta::encoder::encode_metadata::{closure#1}, (), ()>
  39:        0x1106ee348 - rustc_metadata[f2a84a8141f6c436]::rmeta::encoder::encode_metadata
  40:        0x11068928c - rustc_metadata[f2a84a8141f6c436]::fs::encode_and_write_metadata
  41:        0x10d066d9c - rustc_interface[5a3a908aa1aef180]::passes::start_codegen
  42:        0x10d052850 - <rustc_middle[662f54c0a25f7c56]::ty::context::GlobalCtxt>::enter::<<rustc_interface[5a3a908aa1aef180]::queries::Queries>::ongoing_codegen::{closure#0}::{closure#0}, core[dc40836e4f3e0da7]::result::Result<alloc[8ca104b1f3df9592]::boxed::Box<dyn core[dc40836e4f3e0da7]::any::Any>, rustc_span[7733720cb78d73dd]::ErrorGuaranteed>>
  43:        0x10d01ea18 - <rustc_interface[5a3a908aa1aef180]::queries::Queries>::ongoing_codegen
  44:        0x10cf8ec74 - <rustc_interface[5a3a908aa1aef180]::interface::Compiler>::enter::<rustc_driver_impl[9431cfa2328e8da]::run_compiler::{closure#1}::{closure#2}, core[dc40836e4f3e0da7]::result::Result<core[dc40836e4f3e0da7]::option::Option<rustc_interface[5a3a908aa1aef180]::queries::Linker>, rustc_span[7733720cb78d73dd]::ErrorGuaranteed>>
  45:        0x10cf52ca4 - rustc_span[7733720cb78d73dd]::set_source_map::<core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>, rustc_interface[5a3a908aa1aef180]::interface::run_compiler<core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>, rustc_driver_impl[9431cfa2328e8da]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  46:        0x10cf58250 - <scoped_tls[4e67b4d1df739e32]::ScopedKey<rustc_span[7733720cb78d73dd]::SessionGlobals>>::set::<rustc_interface[5a3a908aa1aef180]::interface::run_compiler<core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>, rustc_driver_impl[9431cfa2328e8da]::run_compiler::{closure#1}>::{closure#0}, core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>>
  47:        0x10cf49a1c - std[614eb408c5fa570d]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[5a3a908aa1aef180]::util::run_in_thread_pool_with_globals<rustc_interface[5a3a908aa1aef180]::interface::run_compiler<core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>, rustc_driver_impl[9431cfa2328e8da]::run_compiler::{closure#1}>::{closure#0}, core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>>
  48:        0x10cf5d42c - <<std[614eb408c5fa570d]::thread::Builder>::spawn_unchecked_<rustc_interface[5a3a908aa1aef180]::util::run_in_thread_pool_with_globals<rustc_interface[5a3a908aa1aef180]::interface::run_compiler<core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>, rustc_driver_impl[9431cfa2328e8da]::run_compiler::{closure#1}>::{closure#0}, core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[dc40836e4f3e0da7]::result::Result<(), rustc_span[7733720cb78d73dd]::ErrorGuaranteed>>::{closure#1} as core[dc40836e4f3e0da7]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  49:        0x104a9bcd0 - std::sys::unix::thread::Thread::new::thread_start::h02c2263b1a3b4fc6
  50:        0x19840bfa8 - __pthread_joiner_wake

bisect command:

cargo bisect-rustc --start 2023-04-17 --end 2023-04-18 --without-cargo -- build --release

bisect result: #109247

---

Regression in 5546cb6

---

[matthiaskrgr]

uuh cc @saethlin

[matthiaskrgr]

For repro:
git clone https://github.com/ferrilab/bitvec/ ; cd bitvec ; git checkout 20e2d68 ; cargo build --release

[saethlin]

You're right that this ICEs after my PR but not before, but this looks like an issue related to type system code or ElaborateDrops, not MIR inlining itself, so I don't think I can't help here.

[matthiaskrgr]

Ah so it would have iced before if we had forced inlining before?

[saethlin]

Yes, with enough application of #[inline(always)] this code should ICE before that PR. I couldn't tell you where to apply the attribute though, just squinting at the ICE message it looks like this closure#0 is significant, though I don't know enough to track down where that closure is.

[matthiaskrgr]

Is there some rustc flag I can use to force inlining of like ~ everything ~ for testing purposes? 👀

edit: -Zinline-mir-threshold=0 or something like that? :D

[saethlin]

-Zinline-mir-threshold=10000 -Zinline-mir-hint-threshold=10000 You need to set both thresholds, and I don't think we have a magic value for "always", just use a big number. The defaults are 50 and 100 I think.

Also just FYI there's also an inlining depth limit that's not configurable, but it shouldn't be relevant for this PR. But if you see unexpected missed inlinings even with passing those flags, that threshold might be why.

[saethlin]

Oh, those flags won't help you before the PR in question, because functions without #[inline] are simply not considered for inlining at all, no matter their size. Fixing this odd ignoring of size was the whole point of that PR.

You can pass -Zmir-opt-level=3 to lift that "must have #[inline]" requirement, but of course that turns on other passes, but the check you're trying to dodge is an explicit check for the MIR opt level inside the Inline pass so... yeah just you might also hit other bugs. You could try turning off the passes that are enabled at mir-opt-level=3 but that would be messy.

[matthiaskrgr]

The mir opt level is cranked up already anyway https://github.com/matthiaskrgr/icemaker/blob/master/src/flags.rs#L137
Maybe I can find some snippet that somehow reassembles what we are seeing here :)

I'll be able to report back in an hour or so I guess ^^

[matthiaskrgr]

Meh besides a couple more "hangs" (process timeouts) nothing new in the standard rustc test set :/