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