ICE: bound types encountered in super_relate_tys non_lifetime_binders

[matthiaskrgr]

Code

#![feature(non_lifetime_binders)]
#![crate_type = "lib"]

trait Trait<Input> {
    type Output;
}

async fn walk2<F: 'a>(filter: F)
where
    for<F> F: Trait<&'a u32> + 'a,
{}

fn main() {}

Meta

rustc --version --verbose:

rustc 1.69.0-nightly (9aa5c24b7 2023-02-17)
binary: rustc
commit-hash: 9aa5c24b7d763fb98d998819571128ff2eb8a3ca
commit-date: 2023-02-17
host: x86_64-unknown-linux-gnu
release: 1.69.0-nightly
LLVM version: 15.0.7

Error output

error[E0670]: `async fn` is not permitted in Rust 2015
 --> /tmp/im/2ec83234343195293d1cafeb6c8dd3911c99ba01.rs:8:1
  |
8 | async fn walk2<F: 'a>(filter: F)
  | ^^^^^ to use `async fn`, switch to Rust 2018 or later
  |
  = help: pass `--edition 2021` to `rustc`
  = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0261]: use of undeclared lifetime name `'a`
 --> /tmp/im/2ec83234343195293d1cafeb6c8dd3911c99ba01.rs:8:19
  |
8 | async fn walk2<F: 'a>(filter: F)
  |                -  ^^ undeclared lifetime
  |                |
  |                help: consider introducing lifetime `'a` here: `'a,`

error[E0261]: use of undeclared lifetime name `'a`
  --> /tmp/im/2ec83234343195293d1cafeb6c8dd3911c99ba01.rs:10:22
   |
10 |     for<F> F: Trait<&'a u32> + 'a,
   |                      ^^ undeclared lifetime
   |
   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the bound lifetime-generic with a new `'a` lifetime
   |
10 |     for<F> F: for<'a> Trait<&'a u32> + 'a,
   |               +++++++
help: consider making the bound lifetime-generic with a new `'a` lifetime
   |
10 |     for<'a, F> F: Trait<&'a u32> + 'a,
   |         +++
help: consider introducing lifetime `'a` here
   |
8  | async fn walk2<'a, F: 'a>(filter: F)
   |                +++

error[E0261]: use of undeclared lifetime name `'a`
  --> /tmp/im/2ec83234343195293d1cafeb6c8dd3911c99ba01.rs:10:32
   |
10 |     for<F> F: Trait<&'a u32> + 'a,
   |                                ^^ undeclared lifetime
   |
help: consider making the bound lifetime-generic with a new `'a` lifetime
   |
10 |     for<'a, F> F: Trait<&'a u32> + 'a,
   |         +++
help: consider introducing lifetime `'a` here
   |
8  | async fn walk2<'a, F: 'a>(filter: F)
   |                +++

warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes
 --> /tmp/im/2ec83234343195293d1cafeb6c8dd3911c99ba01.rs:1:12
  |
1 | #![feature(non_lifetime_binders)]
  |            ^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #1 <https://github.com/rust-lang/rust/issues/1> for more information
  = note: `#[warn(incomplete_features)]` on by default

Backtrace

error: internal compiler error: /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/compiler/rustc_middle/src/ty/relate.rs:412:13: bound types encountered in super_relate_tys

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/compiler/rustc_errors/src/lib.rs:1642:9
stack backtrace:
   0:     0x7f36b496aa5a - std::backtrace_rs::backtrace::libunwind::trace::hf4a48a91b677bc8d
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f36b496aa5a - std::backtrace_rs::backtrace::trace_unsynchronized::h52302266f2c9e2af
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f36b496aa5a - std::sys_common::backtrace::_print_fmt::h00aaca457620efb0
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7f36b496aa5a - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h6d9f10455e422cbd
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f36b49ca9ae - core::fmt::write::h065585aa0e682316
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/core/src/fmt/mod.rs:1232:17
   5:     0x7f36b495ae05 - std::io::Write::write_fmt::h54937c0abd9a719d
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/io/mod.rs:1684:15
   6:     0x7f36b496a825 - std::sys_common::backtrace::_print::h0141838be2b7fc59
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/sys_common/backtrace.rs:47:5
   7:     0x7f36b496a825 - std::sys_common::backtrace::print::h422705047959e0cf
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/sys_common/backtrace.rs:34:9
   8:     0x7f36b496d59f - std::panicking::default_hook::{{closure}}::h04c227824228bc2c
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/panicking.rs:267:22
   9:     0x7f36b496d2db - std::panicking::default_hook::h1a17cdb165515d8b
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/panicking.rs:286:9
  10:     0x7f36b7c60224 - rustc_driver_impl[9b756e32c0d38789]::DEFAULT_HOOK::{closure#0}::{closure#0}
  11:     0x7f36b496dddd - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h7593a5eec671dafe
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/alloc/src/boxed.rs:2002:9
  12:     0x7f36b496dddd - std::panicking::rust_panic_with_hook::h815681ed9ae37db1
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/panicking.rs:692:13
  13:     0x7f36b821c361 - std[92d2792449a90a80]::panicking::begin_panic::<rustc_errors[c2c7aee1e156d1f6]::ExplicitBug>::{closure#0}
  14:     0x7f36b8213fd6 - std[92d2792449a90a80]::sys_common::backtrace::__rust_end_short_backtrace::<std[92d2792449a90a80]::panicking::begin_panic<rustc_errors[c2c7aee1e156d1f6]::ExplicitBug>::{closure#0}, !>
  15:     0x7f36b816d676 - std[92d2792449a90a80]::panicking::begin_panic::<rustc_errors[c2c7aee1e156d1f6]::ExplicitBug>
  16:     0x7f36b82128d6 - std[92d2792449a90a80]::panic::panic_any::<rustc_errors[c2c7aee1e156d1f6]::ExplicitBug>
  17:     0x7f36b82127c6 - <rustc_errors[c2c7aee1e156d1f6]::HandlerInner>::bug::<&alloc[77fdffdb8c1c6cb]::string::String>
  18:     0x7f36b8212490 - <rustc_errors[c2c7aee1e156d1f6]::Handler>::bug::<&alloc[77fdffdb8c1c6cb]::string::String>
  19:     0x7f36b827972b - rustc_middle[b5631d71f72482ee]::util::bug::opt_span_bug_fmt::<rustc_span[65551fbbac8b0f76]::span_encoding::Span>::{closure#0}
  20:     0x7f36b8278eea - rustc_middle[b5631d71f72482ee]::ty::context::tls::with_opt::<rustc_middle[b5631d71f72482ee]::util::bug::opt_span_bug_fmt<rustc_span[65551fbbac8b0f76]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7f36b8278eb6 - rustc_middle[b5631d71f72482ee]::ty::context::tls::with_context_opt::<rustc_middle[b5631d71f72482ee]::ty::context::tls::with_opt<rustc_middle[b5631d71f72482ee]::util::bug::opt_span_bug_fmt<rustc_span[65551fbbac8b0f76]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7f36b8279676 - rustc_middle[b5631d71f72482ee]::util::bug::opt_span_bug_fmt::<rustc_span[65551fbbac8b0f76]::span_encoding::Span>
  23:     0x7f36b5f35973 - rustc_middle[b5631d71f72482ee]::util::bug::bug_fmt
  24:     0x7f36b6524b03 - rustc_middle[b5631d71f72482ee]::ty::relate::super_relate_tys::<rustc_infer[e7333a217508eb8e]::infer::outlives::test_type_match::Match>
  25:     0x7f36b65246d0 - rustc_infer[e7333a217508eb8e]::infer::outlives::test_type_match::can_match_erased_ty
  26:     0x7f36b6521fae - <rustc_infer[e7333a217508eb8e]::infer::outlives::verify::VerifyBoundCx>::declared_generic_bounds_from_env_for_erased_ty
  27:     0x7f36b651af7b - <rustc_infer[e7333a217508eb8e]::infer::outlives::obligations::TypeOutlives<&mut rustc_borrowck[2bd7762540f7a794]::type_check::constraint_conversion::ConstraintConversion>>::components_must_outlive
  28:     0x7f36b6c2445a - <rustc_borrowck[2bd7762540f7a794]::type_check::constraint_conversion::ConstraintConversion>::convert_all
  29:     0x7f36b6c071d3 - <rustc_borrowck[2bd7762540f7a794]::type_check::TypeChecker>::typeck_mir
  30:     0x7f36b6b79dbf - rustc_borrowck[2bd7762540f7a794]::nll::compute_regions
  31:     0x7f36b6b4ba3c - rustc_borrowck[2bd7762540f7a794]::do_mir_borrowck
  32:     0x7f36b6b38458 - rustc_borrowck[2bd7762540f7a794]::mir_borrowck
  33:     0x7f36b65bfb6b - rustc_query_system[2b3be6912aef78d5]::query::plumbing::try_execute_query::<rustc_query_impl[a3402ef8368c6710]::queries::mir_borrowck, rustc_query_impl[a3402ef8368c6710]::plumbing::QueryCtxt>
  34:     0x7f36b765bd3d - <rustc_query_impl[a3402ef8368c6710]::Queries as rustc_middle[b5631d71f72482ee]::ty::query::QueryEngine>::mir_borrowck
  35:     0x7f36b71cf5e2 - rustc_hir_analysis[90a2d534158d44df]::collect::type_of::type_of
  36:     0x7f36b66c0ad1 - rustc_query_system[2b3be6912aef78d5]::query::plumbing::get_query::<rustc_query_impl[a3402ef8368c6710]::queries::type_of, rustc_query_impl[a3402ef8368c6710]::plumbing::QueryCtxt, rustc_middle[b5631d71f72482ee]::dep_graph::dep_node::DepKind>
  37:     0x7f36b65c5314 - rustc_hir_analysis[90a2d534158d44df]::check::check::check_mod_item_types
  38:     0x7f36b722229f - rustc_query_system[2b3be6912aef78d5]::query::plumbing::try_execute_query::<rustc_query_impl[a3402ef8368c6710]::queries::check_mod_item_types, rustc_query_impl[a3402ef8368c6710]::plumbing::QueryCtxt>
  39:     0x7f36b765b32d - <rustc_query_impl[a3402ef8368c6710]::Queries as rustc_middle[b5631d71f72482ee]::ty::query::QueryEngine>::check_mod_item_types
  40:     0x7f36b610781d - <rustc_middle[b5631d71f72482ee]::hir::map::Map>::for_each_module::<rustc_hir_analysis[90a2d534158d44df]::check_crate::{closure#6}::{closure#0}>
  41:     0x7f36b61052ad - rustc_hir_analysis[90a2d534158d44df]::check_crate
  42:     0x7f36b60fad72 - rustc_interface[828b714f964ce1da]::passes::analysis
  43:     0x7f36b744d4f2 - rustc_query_system[2b3be6912aef78d5]::query::plumbing::try_execute_query::<rustc_query_impl[a3402ef8368c6710]::queries::analysis, rustc_query_impl[a3402ef8368c6710]::plumbing::QueryCtxt>
  44:     0x7f36b76550fa - <rustc_query_impl[a3402ef8368c6710]::Queries as rustc_middle[b5631d71f72482ee]::ty::query::QueryEngine>::analysis
  45:     0x7f36b6e75a23 - <rustc_interface[828b714f964ce1da]::queries::QueryResult<&rustc_middle[b5631d71f72482ee]::ty::context::GlobalCtxt>>::enter::<core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>, rustc_driver_impl[9b756e32c0d38789]::run_compiler::{closure#1}::{closure#2}::{closure#3}>
  46:     0x7f36b6e74bf4 - <rustc_interface[828b714f964ce1da]::interface::Compiler>::enter::<rustc_driver_impl[9b756e32c0d38789]::run_compiler::{closure#1}::{closure#2}, core[d0f7fc72c0be1fb4]::result::Result<core[d0f7fc72c0be1fb4]::option::Option<rustc_interface[828b714f964ce1da]::queries::Linker>, rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>>
  47:     0x7f36b6e6fe14 - rustc_span[65551fbbac8b0f76]::with_source_map::<core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>, rustc_interface[828b714f964ce1da]::interface::run_compiler<core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>, rustc_driver_impl[9b756e32c0d38789]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  48:     0x7f36b6e6f924 - <scoped_tls[18b6b4dd1216e2e8]::ScopedKey<rustc_span[65551fbbac8b0f76]::SessionGlobals>>::set::<rustc_interface[828b714f964ce1da]::interface::run_compiler<core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>, rustc_driver_impl[9b756e32c0d38789]::run_compiler::{closure#1}>::{closure#0}, core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>>
  49:     0x7f36b6e6f022 - std[92d2792449a90a80]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[828b714f964ce1da]::util::run_in_thread_pool_with_globals<rustc_interface[828b714f964ce1da]::interface::run_compiler<core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>, rustc_driver_impl[9b756e32c0d38789]::run_compiler::{closure#1}>::{closure#0}, core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>>
  50:     0x7f36b6e6edcc - <<std[92d2792449a90a80]::thread::Builder>::spawn_unchecked_<rustc_interface[828b714f964ce1da]::util::run_in_thread_pool_with_globals<rustc_interface[828b714f964ce1da]::interface::run_compiler<core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>, rustc_driver_impl[9b756e32c0d38789]::run_compiler::{closure#1}>::{closure#0}, core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d0f7fc72c0be1fb4]::result::Result<(), rustc_errors[c2c7aee1e156d1f6]::ErrorGuaranteed>>::{closure#1} as core[d0f7fc72c0be1fb4]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  51:     0x7f36b4977c63 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h24b1cedbd344db9f
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/alloc/src/boxed.rs:1988:9
  52:     0x7f36b4977c63 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb7ac28b0dfacf269
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/alloc/src/boxed.rs:1988:9
  53:     0x7f36b4977c63 - std::sys::unix::thread::Thread::new::thread_start::h67c8d237baa6ad51
                               at /rustc/9aa5c24b7d763fb98d998819571128ff2eb8a3ca/library/std/src/sys/unix/thread.rs:108:17
  54:     0x7f36b4707bb5 - <unknown>
  55:     0x7f36b4789d90 - <unknown>
  56:                0x0 - <unknown>

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 1.69.0-nightly (9aa5c24b7 2023-02-17) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [mir_borrowck] borrow-checking `walk2`
#1 [type_of] computing type of `walk2::{opaque#0}`
#2 [check_mod_item_types] checking item types in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 5 previous errors; 1 warning emitted

Some errors have detailed explanations: E0261, E0670.

[compiler-errors]

Most of the error messages are superfluous, this still ICEs if you use edition 2021 and add a 'a to the generics:

#![feature(non_lifetime_binders)]
#![crate_type = "lib"]

async fn walk2<'a, T: 'a>(_: T)
where
    for<F> F: 'a,
{}

fn main() {}