Clippy panics at `NormalizeAfterErasingRegionsFolder:: normalize_generic_arg_after_erasing_regions` when run on RustPython

[Tyrubias]

When I run cargo clippy on the RustPython project, Clippy panics while compiling RustPython in the NormalizeAfterErasingRegionsFolder:: normalize_generic_arg_after_erasing_regions of rustc. I'm on the M1 Max MacBook Pro running macOS Monterey 12.4.

Edit: the above method is being called from clippy_utils/src/ty.rs#L71

Here is the full backtrace

    Checking rustpython-vm v0.1.2 (/Users/vsong/Downloads/RustPython/vm)
warning: unknown lint: `clippy::needless_match`
   --> vm/src/builtins/function.rs:509:17
    |
509 |         #[allow(clippy::needless_match)] // False positive on nightly
    |                 ^^^^^^^^^^^^^^^^^^^^^^ help: did you mean: `clippy::needless_bool`
    |
    = note: `#[warn(unknown_lints)]` on by default

error: internal compiler error: compiler/rustc_middle/src/ty/normalize_erasing_regions.rs:179:90: Failed to normalize <std::option::Option<&std::option::Option<object::core::PyRef<builtins::pystr::PyStr>>> as std::iter::Iterator>::Item, maybe try to call `try_normalize_erasing_regions` instead

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1160:9
stack backtrace:
   0:        0x1057b3118 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h10cf06316d33e2a9
   1:        0x1057ff808 - core::fmt::write::h1faf18c959c3a8df
   2:        0x1057a5104 - std::io::Write::write_fmt::h86ab231360bc97d2
   3:        0x1057b6e44 - std::panicking::default_hook::{{closure}}::h36e628ffaf3cd44f
   4:        0x1057b6abc - std::panicking::default_hook::h3ee1564a7544e58f
   5:        0x1047eccc8 - clippy_driver[d0264e908c5afe0f]::ICE_HOOK::{closure#0}::{closure#0}
   6:        0x1057b7634 - std::panicking::rust_panic_with_hook::h191339fbd2fe2360
   7:        0x1107d2930 - std[8541ff70ccfedbb0]::panicking::begin_panic::<rustc_errors[677d6d214e1093d1]::ExplicitBug>::{closure#0}
   8:        0x1107d28e8 - std[8541ff70ccfedbb0]::sys_common::backtrace::__rust_end_short_backtrace::<std[8541ff70ccfedbb0]::panicking::begin_panic<rustc_errors[677d6d214e1093d1]::ExplicitBug>::{closure#0}, !>
   9:        0x110aa7238 - std[8541ff70ccfedbb0]::panicking::begin_panic::<rustc_errors[677d6d214e1093d1]::ExplicitBug>
  10:        0x110803df8 - std[8541ff70ccfedbb0]::panic::panic_any::<rustc_errors[677d6d214e1093d1]::ExplicitBug>
  11:        0x110801460 - <rustc_errors[677d6d214e1093d1]::HandlerInner>::bug
  12:        0x1107ff7f4 - <rustc_errors[677d6d214e1093d1]::Handler>::bug
  13:        0x110549224 - rustc_middle[48a4de8117124789]::ty::context::tls::with_opt::<rustc_middle[48a4de8117124789]::util::bug::opt_span_bug_fmt<rustc_span[dd8cd730fd24a84e]::span_encoding::Span>::{closure#0}, ()>
  14:        0x110549298 - rustc_middle[48a4de8117124789]::util::bug::opt_span_bug_fmt::<rustc_span[dd8cd730fd24a84e]::span_encoding::Span>
  15:        0x110a987ec - rustc_middle[48a4de8117124789]::util::bug::bug_fmt
  16:        0x1106af400 - <rustc_middle[48a4de8117124789]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder>::normalize_generic_arg_after_erasing_regions
  17:        0x1106adbdc - <rustc_middle[48a4de8117124789]::ty::normalize_erasing_regions::NormalizeAfterErasingRegionsFolder as rustc_middle[48a4de8117124789]::ty::fold::TypeFolder>::fold_ty
  18:        0x104b014f0 - clippy_utils[df06801d8f7bb650]::ty::get_associated_type
  19:        0x104a1fc6c - clippy_lints[503b9a17ac460ecf]::methods::iter_overeager_cloned::check
  20:        0x10493cd28 - <clippy_lints[503b9a17ac460ecf]::methods::Methods as rustc_lint[5173b4f512a1398f]::passes::LateLintPass>::check_expr
  21:        0x1102b4c0c - <rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects as rustc_lint[5173b4f512a1398f]::passes::LateLintPass>::check_expr
  22:        0x10cc41ef0 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_body::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  23:        0x10cc3de7c - <rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects> as rustc_hir[e48eef9567c76cb6]::intravisit::Visitor>::visit_nested_body
  24:        0x10cc48b04 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_expr::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  25:        0x10cc48688 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_expr::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  26:        0x10cc47c48 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_block::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  27:        0x10cc48b88 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_expr::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  28:        0x10cc41efc - rustc_hir[e48eef9567c76cb6]::intravisit::walk_body::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  29:        0x10cc3de7c - <rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects> as rustc_hir[e48eef9567c76cb6]::intravisit::Visitor>::visit_nested_body
  30:        0x10cc4776c - rustc_hir[e48eef9567c76cb6]::intravisit::walk_impl_item::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  31:        0x10cc3cf60 - <rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects> as rustc_hir[e48eef9567c76cb6]::intravisit::Visitor>::visit_nested_impl_item
  32:        0x10cc42cc4 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_item::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  33:        0x10cc3bff0 - <rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects> as rustc_hir[e48eef9567c76cb6]::intravisit::Visitor>::visit_nested_item
  34:        0x10cc426f4 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_item::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  35:        0x10cc3bff0 - <rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects> as rustc_hir[e48eef9567c76cb6]::intravisit::Visitor>::visit_nested_item
  36:        0x10cc426f4 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_item::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  37:        0x10cc3bff0 - <rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects> as rustc_hir[e48eef9567c76cb6]::intravisit::Visitor>::visit_nested_item
  38:        0x10cc426f4 - rustc_hir[e48eef9567c76cb6]::intravisit::walk_item::<rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>>
  39:        0x10cc3bff0 - <rustc_lint[5173b4f512a1398f]::late::LateContextAndPass<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects> as rustc_hir[e48eef9567c76cb6]::intravisit::Visitor>::visit_nested_item
  40:        0x10cc3ea08 - rustc_lint[5173b4f512a1398f]::late::late_lint_pass_crate::<rustc_lint[5173b4f512a1398f]::late::LateLintPassObjects>
  41:        0x10cc3ef00 - rustc_lint[5173b4f512a1398f]::late::late_lint_crate::<rustc_lint[5173b4f512a1398f]::BuiltinCombinedLateLintPass>
  42:        0x10cce4974 - <rustc_session[d383daeae0c11292]::session::Session>::time::<(), rustc_lint[5173b4f512a1398f]::late::check_crate<rustc_lint[5173b4f512a1398f]::BuiltinCombinedLateLintPass, rustc_interface[2280aded15839b11]::passes::analysis::{closure#5}::{closure#0}::{closure#3}::{closure#0}::{closure#0}>::{closure#0}::{closure#0}>
  43:        0x10ccf8d20 - <core[e180da0f2c78f25f]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[2280aded15839b11]::passes::analysis::{closure#5}::{closure#0}::{closure#3}> as core[e180da0f2c78f25f]::ops::function::FnOnce<()>>::call_once
  44:        0x10ccfa3e0 - <core[e180da0f2c78f25f]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[2280aded15839b11]::passes::analysis::{closure#5}::{closure#0}> as core[e180da0f2c78f25f]::ops::function::FnOnce<()>>::call_once
  45:        0x10cce67ac - <rustc_session[d383daeae0c11292]::session::Session>::time::<(), rustc_interface[2280aded15839b11]::passes::analysis::{closure#5}>
  46:        0x10cc720b4 - rustc_interface[2280aded15839b11]::passes::analysis
  47:        0x10fb53df0 - <rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepGraph<rustc_middle[48a4de8117124789]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[48a4de8117124789]::ty::context::TyCtxt, (), core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>
  48:        0x10fc74a34 - rustc_data_structures[6a7bec35f5e261c6]::stack::ensure_sufficient_stack::<(core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_query_system[91d58cadb6adb151]::dep_graph::graph::DepNodeIndex), rustc_query_system[91d58cadb6adb151]::query::plumbing::execute_job<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, (), core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#3}>
  49:        0x10f94d464 - rustc_query_system[91d58cadb6adb151]::query::plumbing::try_execute_query::<rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt, rustc_query_system[91d58cadb6adb151]::query::caches::DefaultCache<(), core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>>
  50:        0x10f9ecdc4 - rustc_query_system[91d58cadb6adb151]::query::plumbing::get_query::<rustc_query_impl[9309ed91bf96ef41]::queries::analysis, rustc_query_impl[9309ed91bf96ef41]::plumbing::QueryCtxt>
  51:        0x10cb7fd38 - <rustc_interface[2280aded15839b11]::passes::QueryContext>::enter::<rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>
  52:        0x10cb3344c - rustc_interface[2280aded15839b11]::interface::create_compiler_and_run::<core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}>
  53:        0x10cb1acb0 - std[8541ff70ccfedbb0]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[2280aded15839b11]::util::run_in_thread_pool_with_globals<rustc_interface[2280aded15839b11]::interface::run_compiler<core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>
  54:        0x10cb94648 - <<std[8541ff70ccfedbb0]::thread::Builder>::spawn_unchecked_<rustc_interface[2280aded15839b11]::util::run_in_thread_pool_with_globals<rustc_interface[2280aded15839b11]::interface::run_compiler<core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>, rustc_driver[3e35567b0507961a]::run_compiler::{closure#1}>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#0}, core[e180da0f2c78f25f]::result::Result<(), rustc_errors[677d6d214e1093d1]::ErrorReported>>::{closure#1} as core[e180da0f2c78f25f]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  55:        0x1057c2b70 - std::sys::unix::thread::Thread::new::thread_start::h8ccdabc567c5eee0
  56:        0x19768426c - __pthread_deallocate

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.60 (7737e0b5 2022-04-04)

query stack during panic:
#0 [analysis] running analysis passes on this crate
end of query stack
warning: `rustpython-vm` (lib) generated 1 warning
error: could not compile `rustpython-vm`; 1 warning emitted

If there's anything else I can do to help debug this, please let me know! I'm new to Rust and would love to contribute.

[Tyrubias]

I just realize the solution was mentioned in #8662 (comment) and this issue was fixed in #8602