ICE: compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs: unexpected path

[matthiaskrgr]

Code

kinda garbish-y but it reproduces the ICE 🤷

use std::path::Path;

pub use self::imp::Lock;

#[cfg(unix)]
mod imp {
    use std::ffi::{CString, OsStr};
    use std::os::unix::prelude::*;
    use std::path::Path;
    use std::io;
    use libc;

  

    #[derive(Debug)]
    pub struct Lock {
        fd: libc::c_int,
    }

    impl Lock {
        pub fn new(p: &Path,
                   wait: bool,
                   create: bool,
                   exclusive: bool)
                   -> io::Result<Lock> {
            let os: &OsStr = p.as_ref();
            let buf = CString::new(os.as_bytes()).unwrap();
            let open_flags = if create {
                libc::O_RDWR | libc::O_CREAT
            } else {
                libc::O_RDWR
            };

            let fd = unsafe {
                libc::open(buf.as_ptr(), open_flags,
                           libc::S_IRWXU as libc::c_int)
            };

            let cmd = if wait { os::F_SETLKW } else { os::F_SETLK };
            let ret = unsafe {
                
            };
            if ret == -1 {
                let err = io::Error::last_os_error();
                unsafe { libc::close(fd); }
                Err(err)
            } else {
                Ok(Lock { fd: fd })
            }

        }
    }

}

Meta

rustc --version --verbose:

IMPORTANT: this reproduces with MASTER but not yet with NIGHTLY rustc 1.63.0-nightly (e71440575 2022-06-02)

rustc 1.63.0-nightly (e40d5e83d 2022-06-03)
binary: rustc
commit-hash: e40d5e83dc133d093c22c7ff016b10daa4f40dcf
commit-date: 2022-06-03
host: x86_64-unknown-linux-gnu
release: 1.63.0-nightly
LLVM version: 14.0.4

Error output

error[E0432]: unresolved import `libc`
  --> ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:11:9
   |
11 |     use libc;
   |         ^^^^ no `libc` in the root

error[E0433]: failed to resolve: use of undeclared crate or module `os`
  --> ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:39:33
   |
39 |             let cmd = if wait { os::F_SETLKW } else { os::F_SETLK };
   |                                 ^^ use of undeclared crate or module `os`

error[E0433]: failed to resolve: use of undeclared crate or module `os`
  --> ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:39:55
   |
39 |             let cmd = if wait { os::F_SETLKW } else { os::F_SETLK };
   |                                                       ^^ use of undeclared crate or module `os`

warning: unused import: `std::path::Path`
 --> ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:1:5
  |
1 | use std::path::Path;
  |     ^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

error[E0601]: `main` function not found in crate `510c9ceef0960a8c8b6a20e3625ee6c2e10b4052`
  --> ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:54:2
   |
54 | }
   |  ^ consider adding a `main` function to `./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs`

error[E0308]: mismatched types
  --> ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:43:23
   |
43 |             if ret == -1 {
   |                       ^^ expected `()`, found integer

error: internal compiler error: compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs:856:33: unexpected path: def=alloc::ffi::c_str::CString substs=[] path=Path { span: ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:27:23: 27:30 (#0), res: Def(TyAlias, DefId(1:2774 ~ std[4f4f]::ffi::CString)), segments: [PathSegment { ident: CString#0, hir_id: Some(HirId { owner: DefId(0:28 ~ 510c9ceef0960a8c8b6a20e3625ee6c2e10b4052[d1fc]::imp::{impl#0}::new), local_id: 22 }), res: Some(Err), args: None, infer_args: true }] }

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/compiler/rustc_errors/src/lib.rs:1335:9

Backtrace

error: internal compiler error: compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs:856:33: unexpected path: def=alloc::ffi::c_str::CString substs=[] path=Path { span: ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:27:23: 27:30 (#0), res: Def(TyAlias, DefId(1:2774 ~ std[4f4f]::ffi::CString)), segments: [PathSegment { ident: CString#0, hir_id: Some(HirId { owner: DefId(0:28 ~ 510c9ceef0960a8c8b6a20e3625ee6c2e10b4052[d1fc]::imp::{impl#0}::new), local_id: 22 }), res: Some(Err), args: None, infer_args: true }] }

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/compiler/rustc_errors/src/lib.rs:1335:9
stack backtrace:
   0:     0x7f6b6ec9decd - std::backtrace_rs::backtrace::libunwind::trace::hfcd45b45ae488cd5
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f6b6ec9decd - std::backtrace_rs::backtrace::trace_unsynchronized::h405dac851f6cc6a8
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f6b6ec9decd - std::sys_common::backtrace::_print_fmt::h5f6c74a63449dd3f
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x7f6b6ec9decd - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h7d487462c277bf24
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x7f6b6ecf9bac - core::fmt::write::h832d0c8909aada18
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/core/src/fmt/mod.rs:1196:17
   5:     0x7f6b6ec8f5c1 - std::io::Write::write_fmt::h65c8c1822edc4894
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/io/mod.rs:1654:15
   6:     0x7f6b6eca0bb5 - std::sys_common::backtrace::_print::h560a0f4f262236c1
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x7f6b6eca0bb5 - std::sys_common::backtrace::print::h0080326ddadae76c
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x7f6b6eca0bb5 - std::panicking::default_hook::{{closure}}::hc726d21ea0224885
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/panicking.rs:295:22
   9:     0x7f6b6eca08d6 - std::panicking::default_hook::hdcc52b852804bb0b
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/panicking.rs:314:9
  10:     0x7f6b6f4f9f11 - rustc_driver[c7c8f2fedff45b54]::DEFAULT_HOOK::{closure#0}::{closure#0}
  11:     0x7f6b6eca128a - std::panicking::rust_panic_with_hook::h48930cf2efbb5ae2
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/panicking.rs:702:17
  12:     0x7f6b705e7ae1 - std[4f4f1627d3880017]::panicking::begin_panic::<rustc_errors[65331a6f7e432222]::ExplicitBug>::{closure#0}
  13:     0x7f6b705e7556 - std[4f4f1627d3880017]::sys_common::backtrace::__rust_end_short_backtrace::<std[4f4f1627d3880017]::panicking::begin_panic<rustc_errors[65331a6f7e432222]::ExplicitBug>::{closure#0}, !>
  14:     0x7f6b7054ecf6 - std[4f4f1627d3880017]::panicking::begin_panic::<rustc_errors[65331a6f7e432222]::ExplicitBug>
  15:     0x7f6b70572b26 - std[4f4f1627d3880017]::panic::panic_any::<rustc_errors[65331a6f7e432222]::ExplicitBug>
  16:     0x7f6b705722e5 - <rustc_errors[65331a6f7e432222]::HandlerInner>::bug::<&alloc[31c74b9f3315cbc6]::string::String>
  17:     0x7f6b70571dc0 - <rustc_errors[65331a6f7e432222]::Handler>::bug::<&alloc[31c74b9f3315cbc6]::string::String>
  18:     0x7f6b705e4acd - rustc_middle[83233ac63f698a09]::ty::context::tls::with_opt::<rustc_middle[83233ac63f698a09]::util::bug::opt_span_bug_fmt<rustc_span[b73b5b7a1d5e4b08]::span_encoding::Span>::{closure#0}, ()>
  19:     0x7f6b705e4bc6 - rustc_middle[83233ac63f698a09]::util::bug::opt_span_bug_fmt::<rustc_span[b73b5b7a1d5e4b08]::span_encoding::Span>
  20:     0x7f6b705e4b43 - rustc_middle[83233ac63f698a09]::util::bug::bug_fmt
  21:     0x7f6b704a82ba - <rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor>::path_inferred_subst_iter
  22:     0x7f6b704a8833 - <rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[a9ca4d4e6c54b339]::intravisit::Visitor>::visit_expr
  23:     0x7f6b704a86cc - <rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[a9ca4d4e6c54b339]::intravisit::Visitor>::visit_expr
  24:     0x7f6b704beb92 - rustc_hir[a9ca4d4e6c54b339]::intravisit::walk_expr::<rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor>
  25:     0x7f6b704a86de - <rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[a9ca4d4e6c54b339]::intravisit::Visitor>::visit_expr
  26:     0x7f6b704bb80c - rustc_hir[a9ca4d4e6c54b339]::intravisit::walk_local::<rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor>
  27:     0x7f6b704a8348 - <rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[a9ca4d4e6c54b339]::intravisit::Visitor>::visit_local
  28:     0x7f6b704bb657 - rustc_hir[a9ca4d4e6c54b339]::intravisit::walk_block::<rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor>
  29:     0x7f6b704a86de - <rustc_infer[78bfaa2976d36a75]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[a9ca4d4e6c54b339]::intravisit::Visitor>::visit_expr
  30:     0x7f6b70460f84 - <rustc_infer[78bfaa2976d36a75]::infer::InferCtxt>::emit_inference_failure_err
  31:     0x7f6b703b30c2 - <rustc_infer[78bfaa2976d36a75]::infer::InferCtxt as rustc_trait_selection[ae7a9636b275321f]::traits::error_reporting::InferCtxtPrivExt>::maybe_report_ambiguity
  32:     0x7f6b703a6c87 - <rustc_infer[78bfaa2976d36a75]::infer::InferCtxt as rustc_trait_selection[ae7a9636b275321f]::traits::error_reporting::InferCtxtExt>::report_fulfillment_errors
  33:     0x7f6b70af7af3 - <rustc_infer[78bfaa2976d36a75]::infer::InferCtxtBuilder>::enter::<&rustc_middle[83233ac63f698a09]::ty::context::TypeckResults, <rustc_typeck[412d93c49a5cfb7d]::check::inherited::InheritedBuilder>::enter<rustc_typeck[412d93c49a5cfb7d]::check::typeck_with_fallback<rustc_typeck[412d93c49a5cfb7d]::check::typeck::{closure#0}>::{closure#1}, &rustc_middle[83233ac63f698a09]::ty::context::TypeckResults>::{closure#0}>
  34:     0x7f6b70aa6efa - rustc_typeck[412d93c49a5cfb7d]::check::typeck
  35:     0x7f6b7109bbb4 - rustc_query_system[cd54684135f7aede]::query::plumbing::try_execute_query::<rustc_query_impl[5d43592eeec5f58a]::plumbing::QueryCtxt, rustc_query_system[cd54684135f7aede]::query::caches::DefaultCache<rustc_span[b73b5b7a1d5e4b08]::def_id::LocalDefId, &rustc_middle[83233ac63f698a09]::ty::context::TypeckResults>>
  36:     0x7f6b7107623e - <rustc_query_impl[5d43592eeec5f58a]::Queries as rustc_middle[83233ac63f698a09]::ty::query::QueryEngine>::typeck
  37:     0x7f6b70b55ee8 - <rustc_middle[83233ac63f698a09]::hir::map::Map>::par_body_owners::<rustc_typeck[412d93c49a5cfb7d]::check::typeck_item_bodies::{closure#0}>
  38:     0x7f6b71936a7c - rustc_typeck[412d93c49a5cfb7d]::check::typeck_item_bodies
  39:     0x7f6b71c303ac - rustc_query_system[cd54684135f7aede]::query::plumbing::try_execute_query::<rustc_query_impl[5d43592eeec5f58a]::plumbing::QueryCtxt, rustc_query_system[cd54684135f7aede]::query::caches::DefaultCache<(), ()>>
  40:     0x7f6b71c5a8b1 - rustc_query_system[cd54684135f7aede]::query::plumbing::get_query::<rustc_query_impl[5d43592eeec5f58a]::queries::typeck_item_bodies, rustc_query_impl[5d43592eeec5f58a]::plumbing::QueryCtxt>
  41:     0x7f6b7196d3f3 - <rustc_session[3dcad23083b71834]::session::Session>::time::<(), rustc_typeck[412d93c49a5cfb7d]::check_crate::{closure#7}>
  42:     0x7f6b7194a77b - rustc_typeck[412d93c49a5cfb7d]::check_crate
  43:     0x7f6b716e3a57 - rustc_interface[d21641337a9fbe3]::passes::analysis
  44:     0x7f6b71c2649f - rustc_query_system[cd54684135f7aede]::query::plumbing::try_execute_query::<rustc_query_impl[5d43592eeec5f58a]::plumbing::QueryCtxt, rustc_query_system[cd54684135f7aede]::query::caches::DefaultCache<(), core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>>
  45:     0x7f6b71c6ce2e - rustc_query_system[cd54684135f7aede]::query::plumbing::get_query::<rustc_query_impl[5d43592eeec5f58a]::queries::analysis, rustc_query_impl[5d43592eeec5f58a]::plumbing::QueryCtxt>
  46:     0x7f6b716c6a07 - <rustc_interface[d21641337a9fbe3]::passes::QueryContext>::enter::<rustc_driver[c7c8f2fedff45b54]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>
  47:     0x7f6b716b0cc8 - <rustc_interface[d21641337a9fbe3]::interface::Compiler>::enter::<rustc_driver[c7c8f2fedff45b54]::run_compiler::{closure#1}::{closure#2}, core[e20aa153a98323b0]::result::Result<core[e20aa153a98323b0]::option::Option<rustc_interface[d21641337a9fbe3]::queries::Linker>, rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>
  48:     0x7f6b716d44df - rustc_span[b73b5b7a1d5e4b08]::with_source_map::<core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>, rustc_interface[d21641337a9fbe3]::interface::create_compiler_and_run<core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>, rustc_driver[c7c8f2fedff45b54]::run_compiler::{closure#1}>::{closure#1}>
  49:     0x7f6b716b18f2 - <scoped_tls[f8b3eb90e665007e]::ScopedKey<rustc_span[b73b5b7a1d5e4b08]::SessionGlobals>>::set::<rustc_interface[d21641337a9fbe3]::interface::run_compiler<core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>, rustc_driver[c7c8f2fedff45b54]::run_compiler::{closure#1}>::{closure#0}, core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>
  50:     0x7f6b716c708f - std[4f4f1627d3880017]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[d21641337a9fbe3]::util::run_in_thread_pool_with_globals<rustc_interface[d21641337a9fbe3]::interface::run_compiler<core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>, rustc_driver[c7c8f2fedff45b54]::run_compiler::{closure#1}>::{closure#0}, core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>::{closure#0}, core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>
  51:     0x7f6b716c71c9 - <<std[4f4f1627d3880017]::thread::Builder>::spawn_unchecked_<rustc_interface[d21641337a9fbe3]::util::run_in_thread_pool_with_globals<rustc_interface[d21641337a9fbe3]::interface::run_compiler<core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>, rustc_driver[c7c8f2fedff45b54]::run_compiler::{closure#1}>::{closure#0}, core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>::{closure#0}, core[e20aa153a98323b0]::result::Result<(), rustc_errors[65331a6f7e432222]::ErrorGuaranteed>>::{closure#1} as core[e20aa153a98323b0]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  52:     0x7f6b6ecab1b3 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h3752e20e7af2922b
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/alloc/src/boxed.rs:1951:9
  53:     0x7f6b6ecab1b3 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hea44272e5391750e
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/alloc/src/boxed.rs:1951:9
  54:     0x7f6b6ecab1b3 - std::sys::unix::thread::Thread::new::thread_start::h6d31b3f92a2b25ea
                               at /rustc/e40d5e83dc133d093c22c7ff016b10daa4f40dcf/library/std/src/sys/unix/thread.rs:108:17
  55:     0x7f6b6ea835c2 - start_thread
  56:     0x7f6b6eb08584 - __clone
  57:                0x0 - <unknown>

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 1.63.0-nightly (e40d5e83d 2022-06-03) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `imp::<impl at ./510c9ceef0960a8c8b6a20e3625ee6c2e10b4052.rs:20:5: 52:6>::new`
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 6 previous errors; 1 warning emitted

Some errors have detailed explanations: E0308, E0432, E0433, E0601.
For more information about an error, try `rustc --explain E0308`.

[matthiaskrgr]

the assert was added in #89862 which just merged, cc @lcnr

[matthiaskrgr]

reduced a bit further

use std::ffi::CString;

impl Lock {
    pub fn new() {
        if () == -1 {
            CString::new();
        }
    }
}

[dtolnay]

Regression in nightly-2022-06-04. Bisects to #89862.

@rustbot label +regression-from-stable-to-nightly

[dtolnay]

I hit a slightly different manifestation of this in the cxx crate. The minimized repro is:

trait Ambiguous<A> {
    fn method() {}
}

struct One;
struct Two;
struct Struct;

impl Ambiguous<One> for Struct {}
impl Ambiguous<Two> for Struct {}

fn main() {
    <Struct as Ambiguous<_>>::method();
}

$ cargo check
thread 'rustc' panicked at 'range end index 2 out of range for slice of length 1', library/core/src/slice/index.rs:73:5
…

I confirmed that this also bisects to #89862, and is also fixed by #97703, and also occurs in need_type_info::FindInferSourceVisitor, which is why I haven't made a separate issue. But the panic in this case is index out of bounds whereas the original one in this issue involves "unexpected path". @lcnr feel free to grab this test case for #97703 if it's legitimately different from the ones you have already.

Backtrace

thread 'rustc' panicked at 'range end index 2 out of range for slice of length 1', library/core/src/slice/index.rs:73:5
stack backtrace:
   0:     0x7f5bdfb5324d - std::backtrace_rs::backtrace::libunwind::trace::h5ecf6d3c2f2dbed3
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f5bdfb5324d - std::backtrace_rs::backtrace::trace_unsynchronized::h1f34ec78f43478d1
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f5bdfb5324d - std::sys_common::backtrace::_print_fmt::h5eb133ec83ff86d3
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x7f5bdfb5324d - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc8814d47922b5f5b
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x7f5bdfbaefec - core::fmt::write::h871772ca8ace1475
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/core/src/fmt/mod.rs:1196:17
   5:     0x7f5bdfb449e1 - std::io::Write::write_fmt::he514622e09de3df5
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/io/mod.rs:1654:15
   6:     0x7f5bdfb55f35 - std::sys_common::backtrace::_print::hd629e2d6c07b6e79
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x7f5bdfb55f35 - std::sys_common::backtrace::print::h6bddafb613b6308d
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x7f5bdfb55f35 - std::panicking::default_hook::{{closure}}::hf8d6097c4866d273
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/panicking.rs:295:22
   9:     0x7f5bdfb55c56 - std::panicking::default_hook::h44331fd67f31aee4
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/panicking.rs:314:9
  10:     0x7f5be032c6b1 - rustc_driver[7b89ea061d8aedc7]::DEFAULT_HOOK::{closure#0}::{closure#0}
  11:     0x7f5bdfb5660a - std::panicking::rust_panic_with_hook::h51126dbc27bfe5a6
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/panicking.rs:702:17
  12:     0x7f5bdfb56447 - std::panicking::begin_panic_handler::{{closure}}::ha0ed88016ebdcd1e
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/panicking.rs:588:13
  13:     0x7f5bdfb53704 - std::sys_common::backtrace::__rust_end_short_backtrace::h05a84a7ce4d2e529
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/sys_common/backtrace.rs:138:18
  14:     0x7f5bdfb56179 - rust_begin_unwind
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/panicking.rs:584:5
  15:     0x7f5bdfb1b443 - core::panicking::panic_fmt::hc7f457b7c7e09a46
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/core/src/panicking.rs:142:14
  16:     0x7f5bdfbb1816 - core::slice::index::slice_end_index_len_fail_rt::h04ca4b0b6ddf070e
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/core/src/slice/index.rs:73:5
  17:     0x7f5bdfba3707 - core::ops::function::FnOnce::call_once::hb4cbec441e0e0d97
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/core/src/ops/function.rs:248:5
  18:     0x7f5bdfbaa516 - core::intrinsics::const_eval_select::h2fab5eaa67d7a905
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/core/src/intrinsics.rs:2375:5
  19:     0x7f5bdfb1b556 - core::slice::index::slice_end_index_len_fail::ha1557d304be1c61e
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/core/src/slice/index.rs:67:9
  20:     0x7f5be129e20f - <rustc_infer[9b42245fee805938]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[5dbb21eaf9590c92]::intravisit::Visitor>::visit_expr
  21:     0x7f5be129cedc - <rustc_infer[9b42245fee805938]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[5dbb21eaf9590c92]::intravisit::Visitor>::visit_expr
  22:     0x7f5be12afe37 - rustc_hir[5dbb21eaf9590c92]::intravisit::walk_block::<rustc_infer[9b42245fee805938]::infer::error_reporting::need_type_info::FindInferSourceVisitor>
  23:     0x7f5be129ceee - <rustc_infer[9b42245fee805938]::infer::error_reporting::need_type_info::FindInferSourceVisitor as rustc_hir[5dbb21eaf9590c92]::intravisit::Visitor>::visit_expr
  24:     0x7f5be1255714 - <rustc_infer[9b42245fee805938]::infer::InferCtxt>::emit_inference_failure_err
  25:     0x7f5be11a72bb - <rustc_infer[9b42245fee805938]::infer::InferCtxt as rustc_trait_selection[af2ed82902f8af73]::traits::error_reporting::InferCtxtPrivExt>::maybe_report_ambiguity
  26:     0x7f5be119af87 - <rustc_infer[9b42245fee805938]::infer::InferCtxt as rustc_trait_selection[af2ed82902f8af73]::traits::error_reporting::InferCtxtExt>::report_fulfillment_errors
  27:     0x7f5be18f3cb4 - <rustc_infer[9b42245fee805938]::infer::InferCtxtBuilder>::enter::<&rustc_middle[c4bb946b42085c78]::ty::context::TypeckResults, <rustc_typeck[4b1a1a7c06e44333]::check::inherited::InheritedBuilder>::enter<rustc_typeck[4b1a1a7c06e44333]::check::typeck_with_fallback<rustc_typeck[4b1a1a7c06e44333]::check::typeck::{closure#0}>::{closure#1}, &rustc_middle[c4bb946b42085c78]::ty::context::TypeckResults>::{closure#0}>
  28:     0x7f5be188570a - rustc_typeck[4b1a1a7c06e44333]::check::typeck
  29:     0x7f5be29835f0 - <rustc_query_system[a1cbf340ec6d6f93]::dep_graph::graph::DepGraph<rustc_middle[c4bb946b42085c78]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c4bb946b42085c78]::ty::context::TyCtxt, rustc_span[c774ced8c61a5d44]::def_id::LocalDefId, &rustc_middle[c4bb946b42085c78]::ty::context::TypeckResults>
  30:     0x7f5be1eac380 - rustc_query_system[a1cbf340ec6d6f93]::query::plumbing::try_execute_query::<rustc_query_impl[f03dd36fb3d62396]::plumbing::QueryCtxt, rustc_query_system[a1cbf340ec6d6f93]::query::caches::DefaultCache<rustc_span[c774ced8c61a5d44]::def_id::LocalDefId, &rustc_middle[c4bb946b42085c78]::ty::context::TypeckResults>>
  31:     0x7f5be1dd7c0e - <rustc_query_impl[f03dd36fb3d62396]::Queries as rustc_middle[c4bb946b42085c78]::ty::query::QueryEngine>::typeck
  32:     0x7f5be1945708 - <rustc_middle[c4bb946b42085c78]::hir::map::Map>::par_body_owners::<rustc_typeck[4b1a1a7c06e44333]::check::typeck_item_bodies::{closure#0}>
  33:     0x7f5be274218c - rustc_typeck[4b1a1a7c06e44333]::check::typeck_item_bodies
  34:     0x7f5be29a2823 - <rustc_query_system[a1cbf340ec6d6f93]::dep_graph::graph::DepGraph<rustc_middle[c4bb946b42085c78]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c4bb946b42085c78]::ty::context::TyCtxt, (), ()>
  35:     0x7f5be2a4d1d5 - rustc_query_system[a1cbf340ec6d6f93]::query::plumbing::try_execute_query::<rustc_query_impl[f03dd36fb3d62396]::plumbing::QueryCtxt, rustc_query_system[a1cbf340ec6d6f93]::query::caches::DefaultCache<(), ()>>
  36:     0x7f5be2a77331 - rustc_query_system[a1cbf340ec6d6f93]::query::plumbing::get_query::<rustc_query_impl[f03dd36fb3d62396]::queries::typeck_item_bodies, rustc_query_impl[f03dd36fb3d62396]::plumbing::QueryCtxt>
  37:     0x7f5be2778473 - <rustc_session[d1b76e352c1a3b5b]::session::Session>::time::<(), rustc_typeck[4b1a1a7c06e44333]::check_crate::{closure#7}>
  38:     0x7f5be276509b - rustc_typeck[4b1a1a7c06e44333]::check_crate
  39:     0x7f5be251f017 - rustc_interface[94703aee012e7483]::passes::analysis
  40:     0x7f5be299e595 - <rustc_query_system[a1cbf340ec6d6f93]::dep_graph::graph::DepGraph<rustc_middle[c4bb946b42085c78]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c4bb946b42085c78]::ty::context::TyCtxt, (), core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>
  41:     0x7f5be2a431fd - rustc_query_system[a1cbf340ec6d6f93]::query::plumbing::try_execute_query::<rustc_query_impl[f03dd36fb3d62396]::plumbing::QueryCtxt, rustc_query_system[a1cbf340ec6d6f93]::query::caches::DefaultCache<(), core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>>
  42:     0x7f5be2a898ee - rustc_query_system[a1cbf340ec6d6f93]::query::plumbing::get_query::<rustc_query_impl[f03dd36fb3d62396]::queries::analysis, rustc_query_impl[f03dd36fb3d62396]::plumbing::QueryCtxt>
  43:     0x7f5be24dc2a7 - <rustc_interface[94703aee012e7483]::passes::QueryContext>::enter::<rustc_driver[7b89ea061d8aedc7]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>
  44:     0x7f5be24c634f - <rustc_interface[94703aee012e7483]::interface::Compiler>::enter::<rustc_driver[7b89ea061d8aedc7]::run_compiler::{closure#1}::{closure#2}, core[c8091fc9dea0c6cf]::result::Result<core[c8091fc9dea0c6cf]::option::Option<rustc_interface[94703aee012e7483]::queries::Linker>, rustc_errors[ae611370a546922c]::ErrorGuaranteed>>
  45:     0x7f5be24efd3f - rustc_span[c774ced8c61a5d44]::with_source_map::<core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>, rustc_interface[94703aee012e7483]::interface::create_compiler_and_run<core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>, rustc_driver[7b89ea061d8aedc7]::run_compiler::{closure#1}>::{closure#1}>
  46:     0x7f5be24c71e2 - <scoped_tls[a35f89285f520bf3]::ScopedKey<rustc_span[c774ced8c61a5d44]::SessionGlobals>>::set::<rustc_interface[94703aee012e7483]::interface::run_compiler<core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>, rustc_driver[7b89ea061d8aedc7]::run_compiler::{closure#1}>::{closure#0}, core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>
  47:     0x7f5be24dc93f - std[f19dd7bb03296d5c]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[94703aee012e7483]::util::run_in_thread_pool_with_globals<rustc_interface[94703aee012e7483]::interface::run_compiler<core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>, rustc_driver[7b89ea061d8aedc7]::run_compiler::{closure#1}>::{closure#0}, core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>::{closure#0}, core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>
  48:     0x7f5be24dca99 - <<std[f19dd7bb03296d5c]::thread::Builder>::spawn_unchecked_<rustc_interface[94703aee012e7483]::util::run_in_thread_pool_with_globals<rustc_interface[94703aee012e7483]::interface::run_compiler<core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>, rustc_driver[7b89ea061d8aedc7]::run_compiler::{closure#1}>::{closure#0}, core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>::{closure#0}, core[c8091fc9dea0c6cf]::result::Result<(), rustc_errors[ae611370a546922c]::ErrorGuaranteed>>::{closure#1} as core[c8091fc9dea0c6cf]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  49:     0x7f5bdfb60533 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb3d14b8461bee867
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/alloc/src/boxed.rs:1951:9
  50:     0x7f5bdfb60533 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h528c1f598bc32c8b
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/alloc/src/boxed.rs:1951:9
  51:     0x7f5bdfb60533 - std::sys::unix::thread::Thread::new::thread_start::h9efddab2b9d9a6d4
                               at /rustc/a6b8c6954829669a5c4fa320c3e6132edf04fcfc/library/std/src/sys/unix/thread.rs:108:17
  52:     0x7f5bdfa5d609 - start_thread
                               at /build/glibc-SzIz7B/glibc-2.31/nptl/pthread_create.c:477:8
  53:     0x7f5bdf980133 - clone
                               at /build/glibc-SzIz7B/glibc-2.31/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95
  54:                0x0 - <unknown>

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 1.63.0-nightly (a6b8c6954 2022-06-03) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [typeck] type-checking `main`
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
end of query stack

[Dylan-DPC]

Labeling it as p-medium based on the discussion here