ICE: assertion failed: storage.data.is_empty()

[matthiaskrgr]

trait b {
    type c;
}
impl<d> b for &a {
    type c;
}
struct e<f: b> {
    g: f::c,
}
fn h(i: Box<e<&()>>) {}

Version information

rustc 1.87.0-nightly (ed49386d3 2025-02-19)
binary: rustc
commit-hash: ed49386d3aa3a445a9889707fd405df01723eced
commit-date: 2025-02-19
host: x86_64-unknown-linux-gnu
release: 1.87.0-nightly
LLVM version: 20.1.0

Possibly related line of code:

rust/compiler/rustc_infer/src/infer/mod.rs

Lines 947 to 959 in ed49386

	/// Clone the list of variable regions. This is used only during NLL processing
	/// to put the set of region variables into the NLL region context.
	pub fn get_region_var_infos(&self) -> VarInfos {
	let inner = self.inner.borrow();
	assert!(!UndoLogs::<UndoLog<'_>>::in_snapshot(&inner.undo_log));
	let storage = inner.region_constraint_storage.as_ref().expect("regions already resolved");
	assert!(storage.data.is_empty());
	// We clone instead of taking because borrowck still wants to use the
	// inference context after calling this for diagnostics and the new
	// trait solver.
	storage.var_infos.clone()
	}

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc

Program output

error: expected unsuffixed literal, found `,`
 --> /tmp/icemaker_global_tempdir.bnN1TH0mO5US/rustc_testrunner_tmpdir_reporting.eanazHCQiRTn/mvce.rs:2:5
  |
2 |     ,
  |     ^

error[E0261]: use of undeclared lifetime name `'a`
  --> /tmp/icemaker_global_tempdir.bnN1TH0mO5US/rustc_testrunner_tmpdir_reporting.eanazHCQiRTn/mvce.rs:57:25
   |
57 | impl<FN, F, T> Foo for &'a () {
   |      -                  ^^ undeclared lifetime
   |      |
   |      help: consider introducing lifetime `'a` here: `'a,`

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.bnN1TH0mO5US/rustc_testrunner_tmpdir_reporting.eanazHCQiRTn/mvce.rs:99:2
   |
99 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.bnN1TH0mO5US/rustc_testrunner_tmpdir_reporting.eanazHCQiRTn/mvce.rs`

error[E0599]: no method named `foo` found for struct `Box<A>` in the current scope
  --> /tmp/icemaker_global_tempdir.bnN1TH0mO5US/rustc_testrunner_tmpdir_reporting.eanazHCQiRTn/mvce.rs:98:7
   |
98 |     x.foo();
   |       ^^^ method not found in `Box<A>`


thread 'rustc' panicked at compiler/rustc_infer/src/infer/mod.rs:953:9:
assertion failed: storage.data.is_empty()
stack backtrace:
   0:     0x70fac9b9a8e4 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h8474fc63c522d8ef
   1:     0x70faca41a2ac - core::fmt::write::h807495cdc673c9ad
   2:     0x70facb38d291 - std::io::Write::write_fmt::ha095d9f81ce0ab0f
   3:     0x70fac9b9a742 - std::sys::backtrace::BacktraceLock::print::h6697e7571ddb1a7a
   4:     0x70fac9b9cf4e - std::panicking::default_hook::{{closure}}::h809b6cc791b58376
   5:     0x70fac9b9cb24 - std::panicking::default_hook::h552e31dd2ff71c94
   6:     0x70fac8ce8d17 - std[751aac3a1d4a21ec]::panicking::update_hook::<alloc[e70108a9cb6abf43]::boxed::Box<rustc_driver_impl[2db46e11a3788224]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x70fac9b9d7c3 - std::panicking::rust_panic_with_hook::h31b9a9fc06967d1a
   8:     0x70fac9b9d486 - std::panicking::begin_panic_handler::{{closure}}::he085f2b5958febbd
   9:     0x70fac9b9ada9 - std::sys::backtrace::__rust_end_short_backtrace::h3acec7353f287c7e
  10:     0x70fac9b9d17d - rust_begin_unwind
  11:     0x70fac6847050 - core::panicking::panic_fmt::h088f650de8922fae
  12:     0x70fac73a233c - core::panicking::panic::h0c2dbbe9c00f16f5
  13:     0x70fac6b9f498 - rustc_borrowck[8d8027f8fded1919]::nll::compute_regions
  14:     0x70facb536ffe - rustc_borrowck[8d8027f8fded1919]::do_mir_borrowck
  15:     0x70facb52a4ee - rustc_query_impl[db8619f7f72bce84]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[db8619f7f72bce84]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[cad254c74eefe1b7]::query::erase::Erased<[u8; 8usize]>>
  16:     0x70faca7c42cc - rustc_query_system[61afea02fdc7dc5c]::query::plumbing::try_execute_query::<rustc_query_impl[db8619f7f72bce84]::DynamicConfig<rustc_data_structures[7f723801f239d808]::vec_cache::VecCache<rustc_span[3242d24a3aa68a91]::def_id::LocalDefId, rustc_middle[cad254c74eefe1b7]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[61afea02fdc7dc5c]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[db8619f7f72bce84]::plumbing::QueryCtxt, false>
  17:     0x70faca7c3dcc - rustc_query_impl[db8619f7f72bce84]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  18:     0x70faca7cc47a - rustc_interface[8d7befe99ce7adde]::passes::run_required_analyses
  19:     0x70facb38923a - rustc_interface[8d7befe99ce7adde]::passes::analysis
  20:     0x70facb389219 - rustc_query_impl[db8619f7f72bce84]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[db8619f7f72bce84]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[cad254c74eefe1b7]::query::erase::Erased<[u8; 0usize]>>
  21:     0x70facb416883 - rustc_query_system[61afea02fdc7dc5c]::query::plumbing::try_execute_query::<rustc_query_impl[db8619f7f72bce84]::DynamicConfig<rustc_query_system[61afea02fdc7dc5c]::query::caches::SingleCache<rustc_middle[cad254c74eefe1b7]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[db8619f7f72bce84]::plumbing::QueryCtxt, false>
  22:     0x70facb416553 - rustc_query_impl[db8619f7f72bce84]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  23:     0x70facb448f3c - rustc_interface[8d7befe99ce7adde]::passes::create_and_enter_global_ctxt::<core[5038f2ec8886dbab]::option::Option<rustc_interface[8d7befe99ce7adde]::queries::Linker>, rustc_driver_impl[2db46e11a3788224]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  24:     0x70facb43c8ab - rustc_interface[8d7befe99ce7adde]::interface::run_compiler::<(), rustc_driver_impl[2db46e11a3788224]::run_compiler::{closure#0}>::{closure#1}
  25:     0x70facb302dc8 - std[751aac3a1d4a21ec]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[8d7befe99ce7adde]::util::run_in_thread_with_globals<rustc_interface[8d7befe99ce7adde]::util::run_in_thread_pool_with_globals<rustc_interface[8d7befe99ce7adde]::interface::run_compiler<(), rustc_driver_impl[2db46e11a3788224]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  26:     0x70facb3031f4 - <<std[751aac3a1d4a21ec]::thread::Builder>::spawn_unchecked_<rustc_interface[8d7befe99ce7adde]::util::run_in_thread_with_globals<rustc_interface[8d7befe99ce7adde]::util::run_in_thread_pool_with_globals<rustc_interface[8d7befe99ce7adde]::interface::run_compiler<(), rustc_driver_impl[2db46e11a3788224]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[5038f2ec8886dbab]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  27:     0x70facb303baf - std::sys::pal::unix::thread::Thread::new::thread_start::ha52e702df20ec6b5
  28:     0x70fac54a370a - <unknown>
  29:     0x70fac5527aac - <unknown>
  30:                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: please make sure that you have updated to the latest nightly

note: rustc 1.87.0-nightly (ed49386d3 2025-02-19) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [mir_borrowck] borrow-checking `new`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors

Some errors have detailed explanations: E0261, E0599, E0601.
For more information about an error, try `rustc --explain E0261`.

[matthiaskrgr]

smaller

trait b {
    type c;
}
impl<d> b for &a {
    type c;
}
struct e<f: b> {
    g: f::c,
}
fn h(i: Box<e<&()>>) {}