Internal Error When Using maturin develop

[vedantroy]

Don't have time to create a minimal reproducible example, just reporting this in case it is useful.

I think compiling should fail on this commit: automerge/automerge-py@e8d529c

Version: rustc 1.53.0-nightly (d0695c908 2021-04-12)

Backtrace:

🔗 Found pyo3 bindings
🐍 Found CPython 3.9 at python
   Compiling pythonize v0.13.0
   Compiling automerge-frontend v0.1.0 (/home/vedantroy/Desktop/projects/automerge-rs/automerge-frontend)
   Compiling automerge-backend v0.0.1 (/home/vedantroy/Desktop/projects/automerge-rs/automerge-backend)
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(16673432981703479282, 1467797803568624759))`,
 right: `Some(Fingerprint(5975806888970250212, 8218834813059712322))`: found unstable fingerprints for predicates_of(core[ec89]::ops::function::Fn): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Self as std::ops::FnMut<Args>>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:67:21: 67:32 (#0)), (Binder(TraitPredicate(<Args as std::marker::Sized>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:67:14: 67:18 (#0)), (Binder(TraitPredicate(<Self as std::ops::Fn<Args>>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:67:1: 67:32 (#0))] }', /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/compiler/rustc_query_system/src/query/plumbing.rs:593:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/core/src/panicking.rs:92:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: rustc_query_system::query::plumbing::incremental_verify_ich
   5: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory
   6: rustc_query_system::query::plumbing::get_query_impl
   7: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
   8: rustc_typeck::outlives::explicit::ExplicitPredicatesMap::explicit_predicates_of
   9: rustc_typeck::outlives::implicit_infer::check_explicit_predicates
  10: <rustc_typeck::outlives::implicit_infer::InferVisitor as rustc_hir::itemlikevisit::ItemLikeVisitor>::visit_item
  11: rustc_hir::hir::Crate::visit_all_item_likes
  12: rustc_typeck::outlives::inferred_outlives_crate
  13: rustc_query_impl::<impl rustc_query_system::query::config::QueryAccessors<rustc_query_impl::plumbing::QueryCtxt> for rustc_query_impl::queries::inferred_outlives_crate>::compute
  14: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  15: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  16: rustc_data_structures::stack::ensure_sufficient_stack
  17: rustc_query_system::query::plumbing::force_query_with_job
  18: rustc_query_system::query::plumbing::get_query_impl
  19: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::inferred_outlives_crate
  20: rustc_typeck::outlives::inferred_outlives_of
  21: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  22: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  23: rustc_data_structures::stack::ensure_sufficient_stack
  24: rustc_query_system::query::plumbing::force_query_with_job
  25: rustc_query_system::query::plumbing::force_query_impl
  26: rustc_query_impl::query_callbacks::inferred_outlives_of::force_from_dep_node
  27: rustc_query_system::dep_graph::graph::DepGraph<K>::try_mark_previous_green
  28: rustc_query_system::dep_graph::graph::DepGraph<K>::try_mark_previous_green
  29: rustc_query_system::dep_graph::graph::DepGraph<K>::try_mark_green_and_read
  30: rustc_query_system::query::plumbing::ensure_must_run
  31: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
  32: rustc_typeck::collect::convert_item
  33: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_item
  34: rustc_middle::hir::map::Map::visit_item_likes_in_module
  35: rustc_typeck::collect::collect_mod_item_types
  36: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  37: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  38: rustc_query_system::query::plumbing::force_query_with_job
  39: rustc_query_system::query::plumbing::get_query_impl
  40: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::collect_mod_item_types
  41: rustc_session::session::Session::track_errors
  42: rustc_typeck::check_crate
  43: rustc_interface::passes::analysis
  44: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  45: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  46: rustc_data_structures::stack::ensure_sufficient_stack
  47: rustc_query_system::query::plumbing::force_query_with_job
  48: rustc_query_system::query::plumbing::get_query_impl
  49: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  50: rustc_interface::passes::QueryContext::enter
  51: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  52: rustc_span::with_source_map
  53: rustc_interface::interface::create_compiler_and_run
  54: 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 1.53.0-nightly (d0695c908 2021-04-12) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [predicates_of] computing predicates of `std::ops::Fn`
#1 [inferred_outlives_crate] computing the inferred outlives predicates for items in this crate
#2 [inferred_outlives_of] computing inferred outlives predicates of `Frontend`
#3 [collect_mod_item_types] collecting item types in top-level module
#4 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `automerge-frontend`

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(8011764188665035206, 11945345768445458077))`,
 right: `Some(Fingerprint(3473410266020365412, 4442319614701104323))`: found unstable fingerprints for predicates_of(core[ec89]::fmt::Debug): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Self as std::fmt::Debug>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/fmt/mod.rs:552:1: 552:16 (#0))] }', /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/compiler/rustc_query_system/src/query/plumbing.rs:593:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/core/src/panicking.rs:92:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: rustc_query_system::query::plumbing::incremental_verify_ich
   5: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory
   6: rustc_query_system::query::plumbing::get_query_impl
   7: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
   8: rustc_trait_selection::traits::wf::WfPredicates::nominal_obligations
   9: rustc_trait_selection::traits::wf::WfPredicates::compute_trait_ref
  10: rustc_trait_selection::traits::wf::trait_obligations
  11: rustc_infer::infer::InferCtxtBuilder::enter
  12: rustc_typeck::check::wfcheck::check_item_well_formed
  13: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  14: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  15: rustc_query_system::query::plumbing::force_query_with_job
  16: rustc_query_system::query::plumbing::get_query_impl
  17: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_item_well_formed
  18: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::intravisit::Visitor>::visit_item
  19: rustc_data_structures::sync::par_for_each_in
  20: rustc_hir::hir::Crate::par_visit_all_item_likes
  21: rustc_session::session::Session::track_errors
  22: rustc_typeck::check_crate
  23: rustc_interface::passes::analysis
  24: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  25: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  26: rustc_data_structures::stack::ensure_sufficient_stack
  27: rustc_query_system::query::plumbing::force_query_with_job
  28: rustc_query_system::query::plumbing::get_query_impl
  29: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  30: rustc_interface::passes::QueryContext::enter
  31: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  32: rustc_span::with_source_map
  33: rustc_interface::interface::create_compiler_and_run
  34: 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 1.53.0-nightly (d0695c908 2021-04-12) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [predicates_of] computing predicates of `std::fmt::Debug`
#1 [check_item_well_formed] checking that `backend::<impl at /home/vedantroy/Desktop/projects/automerge-rs/automerge-backend/src/backend.rs:13:10: 13:15>` is well-formed
#2 [analysis] running analysis passes on this crate
end of query stack
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(4645450520973734680, 8900769266816580686))`,
 right: `Some(Fingerprint(1277234981224438905, 11121703156189715810))`: found unstable fingerprints for predicates_of(core[ec89]::marker::StructuralPartialEq): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Self as std::marker::StructuralPartialEq>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/marker.rs:152:1: 152:30 (#0))] }', /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/compiler/rustc_query_system/src/query/plumbing.rs:593:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/core/src/panicking.rs:92:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: rustc_query_system::query::plumbing::incremental_verify_ich
   5: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory
   6: rustc_query_system::query::plumbing::get_query_impl
   7: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
   8: rustc_trait_selection::traits::wf::WfPredicates::nominal_obligations
   9: rustc_trait_selection::traits::wf::WfPredicates::compute_trait_ref
  10: rustc_trait_selection::traits::wf::trait_obligations
  11: rustc_infer::infer::InferCtxtBuilder::enter
  12: rustc_typeck::check::wfcheck::check_item_well_formed
  13: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  14: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  15: rustc_query_system::query::plumbing::force_query_with_job
  16: rustc_query_system::query::plumbing::get_query_impl
  17: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_item_well_formed
  18: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::intravisit::Visitor>::visit_item
  19: rustc_data_structures::sync::par_for_each_in
  20: rustc_hir::hir::Crate::par_visit_all_item_likes
  21: rustc_session::session::Session::track_errors
  22: rustc_typeck::check_crate
  23: rustc_interface::passes::analysis
  24: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  25: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  26: rustc_data_structures::stack::ensure_sufficient_stack
  27: rustc_query_system::query::plumbing::force_query_with_job
  28: rustc_query_system::query::plumbing::get_query_impl
  29: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  30: rustc_interface::passes::QueryContext::enter
  31: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  32: rustc_span::with_source_map
  33: rustc_interface::interface::create_compiler_and_run
  34: 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 1.53.0-nightly (d0695c908 2021-04-12) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [predicates_of] computing predicates of `std::marker::StructuralPartialEq`
#1 [check_item_well_formed] checking that `backend::<impl at /home/vedantroy/Desktop/projects/automerge-rs/automerge-backend/src/backend.rs:13:17: 13:26>` is well-formed
#2 [analysis] running analysis passes on this crate
end of query stack
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(11785395142427440122, 11218906968484794210))`,
 right: `Some(Fingerprint(8320454547743849577, 966053870340683749))`: found unstable fingerprints for predicates_of(core[ec89]::cmp::PartialEq): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Self as std::cmp::PartialEq<Rhs>>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/cmp.rs:202:1: 202:40 (#0))] }', /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/compiler/rustc_query_system/src/query/plumbing.rs:593:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/core/src/panicking.rs:92:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: rustc_query_system::query::plumbing::incremental_verify_ich
   5: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory
   6: rustc_query_system::query::plumbing::get_query_impl
   7: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
   8: rustc_trait_selection::traits::wf::WfPredicates::nominal_obligations
   9: rustc_trait_selection::traits::wf::WfPredicates::compute_trait_ref
  10: rustc_trait_selection::traits::wf::trait_obligations
  11: rustc_infer::infer::InferCtxtBuilder::enter
  12: rustc_typeck::check::wfcheck::check_item_well_formed
  13: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  14: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  15: rustc_query_system::query::plumbing::force_query_with_job
  16: rustc_query_system::query::plumbing::get_query_impl
  17: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_item_well_formed
  18: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::intravisit::Visitor>::visit_item
  19: rustc_data_structures::sync::par_for_each_in
  20: rustc_hir::hir::Crate::par_visit_all_item_likes
  21: rustc_session::session::Session::track_errors
  22: rustc_typeck::check_crate
  23: rustc_interface::passes::analysis
  24: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  25: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  26: rustc_data_structures::stack::ensure_sufficient_stack
  27: rustc_query_system::query::plumbing::force_query_with_job
  28: rustc_query_system::query::plumbing::get_query_impl
  29: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  30: rustc_interface::passes::QueryContext::enter
  31: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  32: rustc_span::with_source_map
  33: rustc_interface::interface::create_compiler_and_run
  34: 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 1.53.0-nightly (d0695c908 2021-04-12) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [predicates_of] computing predicates of `std::cmp::PartialEq`
#1 [check_item_well_formed] checking that `backend::<impl at /home/vedantroy/Desktop/projects/automerge-rs/automerge-backend/src/backend.rs:13:17: 13:26>` is well-formed
#2 [analysis] running analysis passes on this crate
end of query stack
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(16189884022057882967, 10770003292536782650))`,
 right: `Some(Fingerprint(8611502385710304100, 15966338659422354936))`: found unstable fingerprints for predicates_of(core[ec89]::clone::Clone): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Self as std::marker::Sized>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/clone.rs:108:18: 108:23 (#0)), (Binder(TraitPredicate(<Self as std::clone::Clone>), []), /home/vedantroy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/clone.rs:108:1: 108:23 (#0))] }', /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/compiler/rustc_query_system/src/query/plumbing.rs:593:5
stack backtrace:
   0: rust_begin_unwind
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /rustc/d0695c9081b16077d0aed368bccaf437d77ff497/library/core/src/panicking.rs:92:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: rustc_query_system::query::plumbing::incremental_verify_ich
   5: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory
   6: rustc_query_system::query::plumbing::get_query_impl
   7: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
   8: rustc_trait_selection::traits::wf::WfPredicates::nominal_obligations
   9: rustc_trait_selection::traits::wf::WfPredicates::compute_trait_ref
  10: rustc_trait_selection::traits::wf::trait_obligations
  11: rustc_infer::infer::InferCtxtBuilder::enter
  12: rustc_typeck::check::wfcheck::check_item_well_formed
  13: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  14: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  15: rustc_query_system::query::plumbing::force_query_with_job
  16: rustc_query_system::query::plumbing::get_query_impl
  17: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_item_well_formed
  18: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::intravisit::Visitor>::visit_item
  19: rustc_data_structures::sync::par_for_each_in
  20: rustc_hir::hir::Crate::par_visit_all_item_likes
  21: rustc_session::session::Session::track_errors
  22: rustc_typeck::check_crate
  23: rustc_interface::passes::analysis
  24: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  25: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  26: rustc_data_structures::stack::ensure_sufficient_stack
  27: rustc_query_system::query::plumbing::force_query_with_job
  28: rustc_query_system::query::plumbing::get_query_impl
  29: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  30: rustc_interface::passes::QueryContext::enter
  31: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  32: rustc_span::with_source_map
  33: rustc_interface::interface::create_compiler_and_run
  34: 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 1.53.0-nightly (d0695c908 2021-04-12) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [predicates_of] computing predicates of `std::clone::Clone`
#1 [check_item_well_formed] checking that `backend::<impl at /home/vedantroy/Desktop/projects/automerge-rs/automerge-backend/src/backend.rs:13:28: 13:33>` is well-formed
#2 [analysis] running analysis passes on this crate
end of query stack
error: build failed
💥 maturin failed
  Caused by: Failed to build a native library through cargo
  Caused by: Failed to build a native library through cargo
  Caused by: Cargo build finished with "exit code: 101": `cargo rustc --message-format json --manifest-path Cargo.toml --lib --`

[vedantroy]

A cargo clean fixed the issue. Not sure what happened, but maybe not that important?

[Aaron1011]

Duplicate of #84341

[Aaron1011]

This is fixed in the latest nightly