debug-assertion ICE: assertion failed: !value.has_escaping_bound_vars()

[DutchGhost]

Code

fn bug<'a>()
where
    [(); {
        let _: &'a ();
    }]:
{}

Meta

rustc --version --verbose:

rustc 1.45.0 (5c1f21c3b 2020-07-13)

Error output

thread 'rustc' panicked at 'assertion failed: !value.has_escaping_bound_vars()', /checkout/compiler/rustc_middle/src/ty/sty.rs:969:9

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
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 (43012395e 2021-04-01) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z emit-future-incompat-report -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0
query stack during panic:
query stack during panic:
#0 [typeck] type-checking `bug::{constant#0}`
#1 [eval_to_allocation_raw] const-evaluating + checking `bug::{constant#0}`

New backtrace: https://gist.github.com/JohnTitor/8b492f5d69b0b704d618c11da81c05ff

Backtrace

thread 'rustc' panicked at 'Box<Any>', /rustc/5c1f21c3b82297671ad3ae1e8c942d2ca92e84f2/src/libstd/macros.rs:13:23
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1076
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1537
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:198
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:218
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:490
  12: std::panicking::begin_panic
  13: rustc_errors::HandlerInner::span_bug
  14: rustc_errors::Handler::span_bug
  15: rustc_middle::util::bug::opt_span_bug_fmt::{{closure}}
  16: rustc_middle::ty::context::tls::with_opt::{{closure}}
  17: rustc_middle::ty::context::tls::with_opt
  18: rustc_middle::util::bug::opt_span_bug_fmt
  19: rustc_middle::util::bug::span_bug_fmt
  20: rustc_typeck::check::Inherited::register_predicate
  21: <rustc_typeck::check::GatherLocalsVisitor as rustc_hir::intravisit::Visitor>::visit_local
  22: rustc_hir::intravisit::walk_expr
  23: rustc_middle::ty::context::GlobalCtxt::enter_local
  24: rustc_typeck::check::typeck_tables_of
  25: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::typeck_tables_of>::compute
  26: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  27: rustc_data_structures::stack::ensure_sufficient_stack
  28: rustc_query_system::query::plumbing::get_query_impl
  29: rustc_mir::const_eval::eval_queries::const_eval_raw_provider
  30: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::const_eval_raw>::compute
  31: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  32: rustc_data_structures::stack::ensure_sufficient_stack
  33: rustc_query_system::query::plumbing::get_query_impl
  34: rustc_mir::const_eval::eval_queries::const_eval_validated_provider
  35: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::const_eval_validated>::compute
  36: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  37: rustc_data_structures::stack::ensure_sufficient_stack
  38: rustc_query_system::query::plumbing::get_query_impl
  39: rustc_mir::const_eval::eval_queries::const_eval_validated_provider
  40: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::const_eval_validated>::compute
  41: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  42: rustc_data_structures::stack::ensure_sufficient_stack
  43: rustc_query_system::query::plumbing::get_query_impl
  44: rustc_middle::mir::interpret::queries::<impl rustc_middle::ty::context::TyCtxt>::const_eval_global_id
  45: rustc_middle::mir::interpret::queries::<impl rustc_middle::ty::context::TyCtxt>::const_eval_resolve
  46: <rustc_trait_selection::traits::project::AssocTypeNormalizer as rustc_middle::ty::fold::TypeFolder>::fold_const
  47: rustc_middle::ty::structural_impls::<impl rustc_middle::ty::fold::TypeFoldable for &rustc_middle::ty::TyS>::super_fold_with
  48: <rustc_trait_selection::traits::project::AssocTypeNormalizer as rustc_middle::ty::fold::TypeFolder>::fold_ty
  49: rustc_middle::ty::fold::TypeFoldable::fold_with
  50: rustc_middle::ty::fold::TypeFoldable::fold_with
  51: rustc_data_structures::stack::ensure_sufficient_stack
  52: rustc_trait_selection::traits::fully_normalize
  53: rustc_middle::ty::context::GlobalCtxt::enter_local
  54: rustc_trait_selection::traits::do_normalize_predicates
  55: rustc_trait_selection::traits::normalize_param_env_or_error
  56: rustc_ty::ty::param_env
  57: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::param_env>::compute
  58: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  59: rustc_query_system::query::plumbing::get_query_impl
  60: rustc_typeck::check::wfcheck::check_item_well_formed
  61: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::check_item_well_formed>::compute
  62: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  63: rustc_query_system::query::plumbing::get_query_impl
  64: rustc_query_system::query::plumbing::ensure_query_impl
  65: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
  66: rustc_hir::hir::Crate::par_visit_all_item_likes
  67: rustc_typeck::check_crate
  68: rustc_interface::passes::analysis
  69: rustc_middle::ty::query::<impl rustc_query_system::query::config::QueryAccessors<rustc_middle::ty::context::TyCtxt> for rustc_middle::ty::query::queries::analysis>::compute
  70: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  71: rustc_query_system::query::plumbing::get_query_impl
  72: rustc_middle::ty::context::tls::enter_global
  73: rustc_interface::interface::run_compiler_in_existing_thread_pool
  74: rustc_ast::attr::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.45.0 (5c1f21c3b 2020-07-13) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -C codegen-units=1 -C debuginfo=2 --crate-type lib

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

query stack during panic:
#0 [typeck_tables_of] type-checking `bug::{{constant}}#0`
#1 [const_eval_raw] const-evaluating `bug::{{constant}}#0`
#2 [const_eval_validated] const-evaluating + checking `bug::{{constant}}#0`
#3 [const_eval_validated] const-evaluating + checking `bug::{{constant}}#0`
#4 [param_env] computing normalized predicates of `bug`
#5 [check_item_well_formed] checking that `bug` is well-formed
#6 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

error: could not compile `playground`.

This probably is the same as found in #70292, except this hits on stable :)

[DutchGhost]

https://godbolt.org/z/8ns3Kq
1.17 - now ICE's
1.9 - 1.16 just error normally
1.6 - 1.8 also produce an ICE (unreachable code in const_eval.rs)
1.0 - 1.5 just error normally

[lcnr]

This is has a similar cause to #56445.

[spastorino]

Assigning P-high as discussed as part of the Prioritization Working Group procedure and removing I-prioritize.

[Alexendoo]

Since min_const_generics stabilisation this now requires #![feature(const_generics)]

#![feature(const_generics)]

fn bug<'a>()
where
    [(); {
        let _: &'a ();
    }]: ,
{
}

fn main() {}

[JohnTitor]

Seems it has been fixed (finally) in the latest nightly, marking as E-needs-test

[JohnTitor]

Triage: This still triggers ICE with a debug assertion, see #83746 for details.

[carado]

Is there a known workaround to this ? I'm getting this error with the following:

#![feature(const_generics, const_evaluatable_checked)]

pub trait Trait {
    const N: usize;
}

impl<'a> Trait for &'a mut i32 {}

pub fn f<'a>() where [(); <&'a mut i32 as Trait>::N]: {}

[chengniansun]

I think I have found a duplicate.

Code

fn test_ref(x: &u32) -> std::future::Future<Output = u32> + '_ {}
fn u() {
    test_ref & u
}

Meta

rustc --version --verbose:

rustc 1.56.0-nightly (9c25eb7aa 2021-07-25)
binary: rustc
commit-hash: 9c25eb7aa3a71fb951564b0ddf131be59c2c951d
commit-date: 2021-07-25
host: x86_64-unknown-linux-gnu
release: 1.56.0-nightly
LLVM version: 12.0.1

Error output

warning: trait objects without an explicit `dyn` are deprecated
 --> mutant.rs:1:25
  |
1 | fn test_ref(x: &u32) -> std::future::Future<Output = u32> + '_ {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn std::future::Future<Output = u32> + '_`
  |
  = note: `#[warn(bare_trait_objects)]` on by default
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>

error[E0601]: `main` function not found in crate `mutant`
 --> mutant.rs:1:1
  |
1 | / fn test_ref(x: &u32) -> std::future::Future<Output = u32> + '_ {}
2 | | fn u() {
3 | |     test_ref & u
4 | | }
  | |_^ consider adding a `main` function to `mutant.rs`

error[E0746]: return type cannot have an unboxed trait object
 --> mutant.rs:1:25
  |
1 | fn test_ref(x: &u32) -> std::future::Future<Output = u32> + '_ {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
  |
help: use some type `T` that is `T: Sized` as the return type if all return paths have the same type
  |
1 | fn test_ref(x: &u32) -> T {}
  |                         ^
help: use `impl std::future::Future<Output = u32> + '_` as the return type if all return paths have the same type but you want to expose only the trait in the signature
  |
1 | fn test_ref(x: &u32) -> impl std::future::Future<Output = u32> + '_ {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: use a boxed trait object if all return paths implement trait `std::future::Future<Output = u32> + '_`
  |
1 | fn test_ref(x: &u32) -> Box<dyn std::future::Future<Output = u32> + '_> {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

thread 'rustc' panicked at 'assertion failed: !value.has_escaping_bound_vars()', compiler/rustc_middle/src/ty/sty.rs:968:9
note: run with `RUST_BACKTRACE=1` environment variable to display a 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 1.56.0-nightly (9c25eb7aa 2021-07-25) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `u`
#1 [typeck_item_bodies] type-checking all item bodies
end of query stack
error: aborting due to 2 previous errors; 1 warning emitted

Some errors have detailed explanations: E0601, E0746.
For more information about an error, try `rustc --explain E0601`.

Backtrace

warning: trait objects without an explicit `dyn` are deprecated
 --> mutant.rs:1:25
  |
1 | fn test_ref(x: &u32) -> std::future::Future<Output = u32> + '_ {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn std::future::Future<Output = u32> + '_`
  |
  = note: `#[warn(bare_trait_objects)]` on by default
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>

error[E0601]: `main` function not found in crate `mutant`
 --> mutant.rs:1:1
  |
1 | / fn test_ref(x: &u32) -> std::future::Future<Output = u32> + '_ {}
2 | | fn u() {
3 | |     test_ref & u
4 | | }
  | |_^ consider adding a `main` function to `mutant.rs`

error[E0746]: return type cannot have an unboxed trait object
 --> mutant.rs:1:25
  |
1 | fn test_ref(x: &u32) -> std::future::Future<Output = u32> + '_ {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
  |
help: use some type `T` that is `T: Sized` as the return type if all return paths have the same type
  |
1 | fn test_ref(x: &u32) -> T {}
  |                         ^
help: use `impl std::future::Future<Output = u32> + '_` as the return type if all return paths have the same type but you want to expose only the trait in the signature
  |
1 | fn test_ref(x: &u32) -> impl std::future::Future<Output = u32> + '_ {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: use a boxed trait object if all return paths implement trait `std::future::Future<Output = u32> + '_`
  |
1 | fn test_ref(x: &u32) -> Box<dyn std::future::Future<Output = u32> + '_> {}
  |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

thread 'rustc' panicked at 'assertion failed: !value.has_escaping_bound_vars()', compiler/rustc_middle/src/ty/sty.rs:968:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/9c25eb7aa3a71fb951564b0ddf131be59c2c951d/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/9c25eb7aa3a71fb951564b0ddf131be59c2c951d/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/9c25eb7aa3a71fb951564b0ddf131be59c2c951d/library/core/src/panicking.rs:50:5
   3: <rustc_middle::ty::sty::TraitRef as rustc_middle::ty::ToPolyTraitRef>::to_poly_trait_ref
   4: rustc_typeck::check::method::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::lookup_method_in_trait
   5: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::lookup_op_method
   6: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::add_type_neq_err_label
   7: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_overloaded_binop
   8: rustc_typeck::check::op::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_binop
   9: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  10: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  11: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  12: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_return_expr
  13: rustc_typeck::check::check::check_fn
  14: rustc_infer::infer::InferCtxtBuilder::enter
  15: rustc_typeck::check::typeck
  16: rustc_query_system::query::plumbing::get_query_impl
  17: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck
  18: rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::par_body_owners
  19: rustc_typeck::check::typeck_item_bodies
  20: rustc_query_system::query::plumbing::get_query_impl
  21: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck_item_bodies
  22: rustc_session::utils::<impl rustc_session::session::Session>::time
  23: rustc_typeck::check_crate
  24: rustc_interface::passes::analysis
  25: rustc_query_system::query::plumbing::get_query_impl
  26: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  27: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  28: rustc_span::with_source_map
  29: rustc_interface::interface::create_compiler_and_run
  30: 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 1.56.0-nightly (9c25eb7aa 2021-07-25) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `u`
#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 2 previous errors; 1 warning emitted

Some errors have detailed explanations: E0601, E0746.
For more information about an error, try `rustc --explain E0601`.

[lcnr]

from what I can tell this now works even with debug assertions? marking as needs-test.