Compiler panic at region constraints already solved

[ghost]

Code

<code>

Meta

rustc --version --verbose:

rustc 1.56.0-nightly (1f0a591b3 2021-07-30)
binary: rustc
commit-hash: 1f0a591b3a5963a0ab11a35dc525ad9d46f612e4
commit-date: 2021-07-30
host: x86_64-unknown-linux-musl
release: 1.56.0-nightly
LLVM version: 12.0.1

Error output

<output>

Backtrace

thread 'rustc' panicked at 'region constraints already solved', compiler/rustc_infer/src/infer/mod.rs:268:14
stack backtrace:
   0: rust_begin_unwind
             at /rustc/1f0a591b3a5963a0ab11a35dc525ad9d46f612e4/library/std/src/panicking.rs:516:5
   1: core::panicking::panic_fmt
             at /rustc/1f0a591b3a5963a0ab11a35dc525ad9d46f612e4/library/core/src/panicking.rs:93:14
   2: core::option::expect_failed
             at /rustc/1f0a591b3a5963a0ab11a35dc525ad9d46f612e4/library/core/src/option.rs:1578:5
   3: <rustc_infer::infer::canonical::canonicalizer::Canonicalizer as rustc_middle::ty::fold::TypeFolder>::fold_region
   4: rustc_middle::ty::structural_impls::<impl rustc_middle::ty::fold::TypeFoldable for &rustc_middle::ty::TyS>::super_fold_with
   5: rustc_middle::ty::fold::TypeFoldable::fold_with
   6: rustc_middle::ty::structural_impls::<impl rustc_middle::ty::fold::TypeFoldable for &rustc_middle::ty::TyS>::super_fold_with
   7: rustc_middle::ty::structural_impls::<impl rustc_middle::ty::fold::TypeFoldable for &rustc_middle::ty::TyS>::super_fold_with
   8: rustc_middle::ty::fold::TypeFoldable::fold_with
   9: rustc_middle::ty::fold::TypeFoldable::fold_with
  10: rustc_infer::infer::canonical::canonicalizer::Canonicalizer::canonicalize
  11: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::evaluate_obligation
  12: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::evaluate_obligation_no_overflow
  13: rustc_trait_selection::traits::type_known_to_meet_bound_modulo_regions
  14: rustc_mir::borrow_check::diagnostics::move_errors::<impl rustc_mir::borrow_check::MirBorrowckCtxt>::report_move_errors
  15: rustc_mir::borrow_check::do_mir_borrowck
  16: rustc_infer::infer::InferCtxtBuilder::enter
  17: rustc_mir::borrow_check::mir_borrowck
  18: core::ops::function::FnOnce::call_once
  19: rustc_query_system::query::plumbing::get_query_impl
  20: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::mir_borrowck
  21: rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::par_body_owners
  22: rustc_interface::passes::analysis
  23: rustc_query_system::query::plumbing::get_query_impl
  24: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  25: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  26: rustc_span::with_source_map
  27: rustc_interface::interface::create_compiler_and_run
  28: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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 1.56.0-nightly (1f0a591b3 2021-07-30) running on x86_64-unknown-linux-musl

note: compiler flags: -C opt-level=3 -C embed-bitcode=no --crate-type bin

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

query stack during panic:
#0 [mir_borrowck] borrow-checking `game::map::block::<impl at src/game/map/block.rs:29:1: 153:2>::get`
#1 [analysis] running analysis passes on this crate
end of query stack

[fanninpm]

Code

<code>

Are you at liberty to share the code causing this ICE?

[SkiFire13]

This is probably a duplicate of #87657