ICE: asked to assemble builtin bounds of unexpected type: T non_lifetime_binders

[matthiaskrgr]

Code

#![feature(non_lifetime_binders)]
trait X<'a, T>
where
    for<T> (T,): X<'b, str>,
    for<T> T: Clone,
{
    type U: ?Sized;
     final 
}

pub fn main() {}

Meta

rustc --version --verbose:

rustc 1.69.0-nightly (276b75a84 2023-03-04)
binary: rustc
commit-hash: 276b75a843af8822ffe4e395266d9445679a57a4
commit-date: 2023-03-04
host: x86_64-unknown-linux-gnu
release: 1.69.0-nightly
LLVM version: 15.0.7

Error output

error: non-item in item list
 --> 9850c90962de060208b975f23e6328a9228e80a9.rs:8:6
  |
6 | {
  | - item list starts here
7 |     type U: ?Sized;
8 |      final
  |      ^^^^^ non-item starts here
9 | }
  | - item list ends here

error[E0261]: use of undeclared lifetime name `'b`
 --> 9850c90962de060208b975f23e6328a9228e80a9.rs:4:20
  |
4 |     for<T> (T,): X<'b, str>,
  |                    ^^ 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 `'b` lifetime
  |
4 |     for<T> (T,): for<'b> X<'b, str>,
  |                  +++++++
help: consider making the bound lifetime-generic with a new `'b` lifetime
  |
4 |     for<'b, T> (T,): X<'b, str>,
  |         +++
help: consider introducing lifetime `'b` here
  |
2 | trait X<'b, 'a, T>
  |         +++

warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes
 --> 9850c90962de060208b975f23e6328a9228e80a9.rs:1:12
  |
1 | #![feature(non_lifetime_binders)]
  |            ^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information
  = note: `#[warn(incomplete_features)]` on by default

Backtrace

error: internal compiler error: compiler/rustc_trait_selection/src/traits/select/mod.rs:2275:17: asked to assemble builtin bounds of unexpected type: T

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/276b75a843af8822ffe4e395266d9445679a57a4/compiler/rustc_errors/src/lib.rs:1644:9
stack backtrace:
   0:     0x7fdf0e96731a - std::backtrace_rs::backtrace::libunwind::trace::ha0b5b2ec62b5f7eb
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7fdf0e96731a - std::backtrace_rs::backtrace::trace_unsynchronized::hfe092e735c972e7d
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fdf0e96731a - std::sys_common::backtrace::_print_fmt::h63b3d4522a0717d3
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7fdf0e96731a - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h8181b48b7caaac69
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7fdf0e9cab6e - core::fmt::write::h26d08fb661ce6712
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/core/src/fmt/mod.rs:1232:17
   5:     0x7fdf0e95a2c5 - std::io::Write::write_fmt::hb9eb4062a2267a70
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/io/mod.rs:1684:15
   6:     0x7fdf0e9670e5 - std::sys_common::backtrace::_print::hcd4093e79b5f3c88
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/sys_common/backtrace.rs:47:5
   7:     0x7fdf0e9670e5 - std::sys_common::backtrace::print::h3741bf27e30883c8
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/sys_common/backtrace.rs:34:9
   8:     0x7fdf0e969e5f - std::panicking::default_hook::{{closure}}::h313aeead3fa63dc9
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/panicking.rs:271:22
   9:     0x7fdf0e969b9b - std::panicking::default_hook::h741e5add290d4582
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/panicking.rs:290:9
  10:     0x7fdf11bcc745 - <rustc_driver_impl[8dfe1fc355efc7d7]::DEFAULT_HOOK::{closure#0}::{closure#0} as core[546e85f3c7d3dc7d]::ops::function::FnOnce<(&core[546e85f3c7d3dc7d]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  11:     0x7fdf0e96a69d - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h8a71253e78811240
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/alloc/src/boxed.rs:2001:9
  12:     0x7fdf0e96a69d - std::panicking::rust_panic_with_hook::ha625c2834fbe1381
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/panicking.rs:696:13
  13:     0x7fdf12128ee1 - std[c918092902fea026]::panicking::begin_panic::<rustc_errors[1bd8d0818954bdfa]::ExplicitBug>::{closure#0}
  14:     0x7fdf12121816 - std[c918092902fea026]::sys_common::backtrace::__rust_end_short_backtrace::<std[c918092902fea026]::panicking::begin_panic<rustc_errors[1bd8d0818954bdfa]::ExplicitBug>::{closure#0}, !>
  15:     0x7fdf12197a76 - std[c918092902fea026]::panicking::begin_panic::<rustc_errors[1bd8d0818954bdfa]::ExplicitBug>
  16:     0x7fdf121750c6 - std[c918092902fea026]::panic::panic_any::<rustc_errors[1bd8d0818954bdfa]::ExplicitBug>
  17:     0x7fdf12170b26 - <rustc_errors[1bd8d0818954bdfa]::HandlerInner>::bug::<&alloc[be2f7de4eeee214f]::string::String>
  18:     0x7fdf121707f0 - <rustc_errors[1bd8d0818954bdfa]::Handler>::bug::<&alloc[be2f7de4eeee214f]::string::String>
  19:     0x7fdf1216799b - rustc_middle[26362df4813740c2]::util::bug::opt_span_bug_fmt::<rustc_span[9747052e8b44f4f1]::span_encoding::Span>::{closure#0}
  20:     0x7fdf121662ea - rustc_middle[26362df4813740c2]::ty::context::tls::with_opt::<rustc_middle[26362df4813740c2]::util::bug::opt_span_bug_fmt<rustc_span[9747052e8b44f4f1]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7fdf121662b6 - rustc_middle[26362df4813740c2]::ty::context::tls::with_context_opt::<rustc_middle[26362df4813740c2]::ty::context::tls::with_opt<rustc_middle[26362df4813740c2]::util::bug::opt_span_bug_fmt<rustc_span[9747052e8b44f4f1]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7fdf121678e6 - rustc_middle[26362df4813740c2]::util::bug::opt_span_bug_fmt::<rustc_span[9747052e8b44f4f1]::span_encoding::Span>
  23:     0x7fdf102c8683 - rustc_middle[26362df4813740c2]::util::bug::bug_fmt
  24:     0x7fdf102db643 - <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::copy_clone_conditions
  25:     0x7fdf102df9ad - <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::assemble_candidates
  26:     0x7fdf106ef44e - <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::candidate_from_obligation_no_cache
  27:     0x7fdf106ee82f - <rustc_query_system[880cf4cc5243faaf]::dep_graph::graph::DepGraph<rustc_middle[26362df4813740c2]::dep_graph::dep_node::DepKind>>::with_anon_task::<rustc_middle[26362df4813740c2]::ty::context::TyCtxt, <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::in_task<<rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::candidate_from_obligation::{closure#0}::{closure#0}, core[546e85f3c7d3dc7d]::result::Result<core[546e85f3c7d3dc7d]::option::Option<rustc_middle[26362df4813740c2]::traits::select::SelectionCandidate>, rustc_middle[26362df4813740c2]::traits::SelectionError>>::{closure#0}, core[546e85f3c7d3dc7d]::result::Result<core[546e85f3c7d3dc7d]::option::Option<rustc_middle[26362df4813740c2]::traits::select::SelectionCandidate>, rustc_middle[26362df4813740c2]::traits::SelectionError>>
  28:     0x7fdf106e9b81 - <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::evaluate_stack
  29:     0x7fdf106e7f4f - <rustc_query_system[880cf4cc5243faaf]::dep_graph::graph::DepGraph<rustc_middle[26362df4813740c2]::dep_graph::dep_node::DepKind>>::with_anon_task::<rustc_middle[26362df4813740c2]::ty::context::TyCtxt, <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::in_task<<rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::evaluate_trait_predicate_recursively::{closure#0}::{closure#2}, core[546e85f3c7d3dc7d]::result::Result<rustc_middle[26362df4813740c2]::traits::select::EvaluationResult, rustc_middle[26362df4813740c2]::traits::select::OverflowError>>::{closure#0}, core[546e85f3c7d3dc7d]::result::Result<rustc_middle[26362df4813740c2]::traits::select::EvaluationResult, rustc_middle[26362df4813740c2]::traits::select::OverflowError>>
  30:     0x7fdf107fa001 - <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::evaluate_predicate_recursively
  31:     0x7fdf107f7b23 - <rustc_infer[69b66cd70457bffb]::infer::InferCtxt>::probe::<core[546e85f3c7d3dc7d]::result::Result<rustc_middle[26362df4813740c2]::traits::select::EvaluationResult, rustc_middle[26362df4813740c2]::traits::select::OverflowError>, <rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::evaluation_probe<<rustc_trait_selection[fb7b454a414b0aef]::traits::select::SelectionContext>::evaluate_root_obligation::{closure#0}>::{closure#0}>
  32:     0x7fdf101d833e - rustc_traits[aa201a8a808e32a4]::evaluate_obligation::evaluate_obligation
  33:     0x7fdf101d4977 - rustc_query_system[880cf4cc5243faaf]::query::plumbing::try_execute_query::<rustc_query_impl[3d069ec1855645b3]::queries::evaluate_obligation, rustc_query_impl[3d069ec1855645b3]::plumbing::QueryCtxt>
  34:     0x7fdf102f9ff3 - <rustc_infer[69b66cd70457bffb]::infer::InferCtxt as rustc_trait_selection[fb7b454a414b0aef]::traits::query::evaluate_obligation::InferCtxtExt>::predicate_must_hold_considering_regions
  35:     0x7fdf10285826 - <rustc_trait_selection[fb7b454a414b0aef]::traits::fulfill::FulfillProcessor as rustc_data_structures[4afc62e9276c9f3a]::obligation_forest::ObligationProcessor>::process_obligation
  36:     0x7fdf1027d194 - <rustc_data_structures[4afc62e9276c9f3a]::obligation_forest::ObligationForest<rustc_trait_selection[fb7b454a414b0aef]::traits::fulfill::PendingPredicateObligation>>::process_obligations::<rustc_trait_selection[fb7b454a414b0aef]::traits::fulfill::FulfillProcessor>
  37:     0x7fdf10806e70 - <rustc_trait_selection[fb7b454a414b0aef]::traits::engine::ObligationCtxt>::select_all_or_error
  38:     0x7fdf109d4dd0 - rustc_hir_analysis[e3526768c08ece23]::check::wfcheck::check_trait
  39:     0x7fdf109af880 - rustc_hir_analysis[e3526768c08ece23]::check::wfcheck::check_well_formed
  40:     0x7fdf1021bffc - rustc_query_system[880cf4cc5243faaf]::query::plumbing::try_execute_query::<rustc_query_impl[3d069ec1855645b3]::queries::check_well_formed, rustc_query_impl[3d069ec1855645b3]::plumbing::QueryCtxt>
  41:     0x7fdf11053b4f - rustc_data_structures[4afc62e9276c9f3a]::sync::par_for_each_in::<&[rustc_hir[edb09612bbfbfb3b]::hir::ImplItemId], <rustc_middle[26362df4813740c2]::hir::ModuleItems>::par_impl_items<rustc_hir_analysis[e3526768c08ece23]::check::wfcheck::check_mod_type_wf::{closure#1}>::{closure#0}>
  42:     0x7fdf11053720 - rustc_hir_analysis[e3526768c08ece23]::check::wfcheck::check_mod_type_wf
  43:     0x7fdf11251be1 - rustc_query_system[880cf4cc5243faaf]::query::plumbing::try_execute_query::<rustc_query_impl[3d069ec1855645b3]::queries::check_mod_type_wf, rustc_query_impl[3d069ec1855645b3]::plumbing::QueryCtxt>
  44:     0x7fdf1125178a - <rustc_query_impl[3d069ec1855645b3]::Queries as rustc_middle[26362df4813740c2]::ty::query::QueryEngine>::check_mod_type_wf
  45:     0x7fdf1001f818 - rustc_data_structures[4afc62e9276c9f3a]::sync::par_for_each_in::<&[rustc_hir[edb09612bbfbfb3b]::hir_id::OwnerId], <rustc_middle[26362df4813740c2]::hir::map::Map>::par_for_each_module<rustc_hir_analysis[e3526768c08ece23]::check_crate::{closure#5}::{closure#0}::{closure#0}>::{closure#0}>
  46:     0x7fdf1001f6a0 - <rustc_session[225f4463efaf2720]::session::Session>::track_errors::<rustc_hir_analysis[e3526768c08ece23]::check_crate::{closure#5}, ()>
  47:     0x7fdf1001c430 - rustc_hir_analysis[e3526768c08ece23]::check_crate
  48:     0x7fdf100121c2 - rustc_interface[d9b7636f56c3f156]::passes::analysis
  49:     0x7fdf1142bd9d - rustc_query_system[880cf4cc5243faaf]::query::plumbing::try_execute_query::<rustc_query_impl[3d069ec1855645b3]::queries::analysis, rustc_query_impl[3d069ec1855645b3]::plumbing::QueryCtxt>
  50:     0x7fdf1142ba9f - <rustc_query_impl[3d069ec1855645b3]::Queries as rustc_middle[26362df4813740c2]::ty::query::QueryEngine>::analysis
  51:     0x7fdf11256166 - <rustc_middle[26362df4813740c2]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[8dfe1fc355efc7d7]::run_compiler::{closure#1}::{closure#2}::{closure#4}, core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>>
  52:     0x7fdf10e3baa8 - rustc_span[9747052e8b44f4f1]::with_source_map::<core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>, rustc_interface[d9b7636f56c3f156]::interface::run_compiler<core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>, rustc_driver_impl[8dfe1fc355efc7d7]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  53:     0x7fdf10e3312c - std[c918092902fea026]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[d9b7636f56c3f156]::util::run_in_thread_pool_with_globals<rustc_interface[d9b7636f56c3f156]::interface::run_compiler<core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>, rustc_driver_impl[8dfe1fc355efc7d7]::run_compiler::{closure#1}>::{closure#0}, core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>>
  54:     0x7fdf10e32b5a - <<std[c918092902fea026]::thread::Builder>::spawn_unchecked_<rustc_interface[d9b7636f56c3f156]::util::run_in_thread_pool_with_globals<rustc_interface[d9b7636f56c3f156]::interface::run_compiler<core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>, rustc_driver_impl[8dfe1fc355efc7d7]::run_compiler::{closure#1}>::{closure#0}, core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[546e85f3c7d3dc7d]::result::Result<(), rustc_span[9747052e8b44f4f1]::ErrorGuaranteed>>::{closure#1} as core[546e85f3c7d3dc7d]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  55:     0x7fdf0e974593 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h60b30d695443d159
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/alloc/src/boxed.rs:1987:9
  56:     0x7fdf0e974593 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h8728245852e6989e
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/alloc/src/boxed.rs:1987:9
  57:     0x7fdf0e974593 - std::sys::unix::thread::Thread::new::thread_start::h960d7bf108545d46
                               at /rustc/276b75a843af8822ffe4e395266d9445679a57a4/library/std/src/sys/unix/thread.rs:108:17
  58:     0x7fdf0e706bb5 - <unknown>
  59:     0x7fdf0e788d90 - <unknown>
  60:                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 (276b75a84 2023-03-04) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [evaluate_obligation] evaluating trait selection obligation `T: core::clone::Clone`
#1 [check_well_formed] checking that `X` is well-formed
#2 [check_mod_type_wf] checking that types are well-formed in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 3 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0261`.

[compiler-errors]

Minimal:

#![feature(non_lifetime_binders)]

fn foo() where for<T> T: Copy {}

fn main() {
    foo();
}

@rustbot claim