ICE: No bound vars found for "expr || 1 ...

[Badel2]

I'm seeing an internal compiler error on the following input, found by fuzz-rustc:

Code

fn main() {
    2: n([u8; || 1])
}

Error output

error[E0412]: cannot find type `n` in this scope
 --> src/main.rs:2:8
  |
2 |     2: n([u8; || 1])
  |        ^ expecting a type here because of type ascription

error: internal compiler error: compiler/rustc_middle/src/ty/context.rs:2713:21: No bound vars found for "expr || 1 (hir_id=HirId { owner: DefId(0:3 ~ playground[aec1]::main), local_id: 7 })" (HirId { owner: DefId(0:3 ~ playground[aec1]::main), local_id: 7 })

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1169:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

The ICE happens after correctly reporting the error "cannot find type n in this scope", so low priority. Affected versions: I tried nightly 2021-11-12 and stable 1.56.1 and they both show the same ICE.

Backtrace

   Compiling playground v0.0.1 (/playground)
error[E0412]: cannot find type `n` in this scope
 --> src/main.rs:2:8
  |
2 |     2: n([u8; || 1])
  |        ^ expecting a type here because of type ascription

error: internal compiler error: compiler/rustc_middle/src/ty/context.rs:2713:21: No bound vars found for "expr || 1 (hir_id=HirId { owner: DefId(0:3 ~ playground[aec1]::main), local_id: 7 })" (HirId { owner: DefId(0:3 ~ playground[aec1]::main), local_id: 7 })

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1169:9
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: std::panic::panic_any::<rustc_errors::ExplicitBug>
   2: <rustc_errors::HandlerInner>::bug
   3: <rustc_errors::Handler>::bug
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, ()>
   5: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>
   6: rustc_middle::util::bug::bug_fmt
   7: <rustc_middle::ty::context::TyCtxt>::late_bound_vars
   8: <rustc_typeck::check::fn_ctxt::FnCtxt>::supplied_sig_of_closure
   9: <rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_closure
  10: <rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  11: <rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  12: <rustc_infer::infer::InferCtxtBuilder>::enter::<&rustc_middle::ty::context::TypeckResults, <rustc_typeck::check::inherited::InheritedBuilder>::enter<rustc_typeck::check::typeck_with_fallback<rustc_typeck::check::typeck::{closure#0}>::{closure#1}, &rustc_middle::ty::context::TypeckResults>::{closure#0}>
  13: rustc_typeck::check::typeck
  14: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalDefId, &rustc_middle::ty::context::TypeckResults>>
  15: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck
  16: rustc_typeck::check::typeck
  17: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalDefId, &rustc_middle::ty::context::TypeckResults>>
  18: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck
  19: <rustc_middle::hir::map::Map>::par_body_owners::<rustc_typeck::check::typeck_item_bodies::{closure#0}>
  20: rustc_typeck::check::typeck_item_bodies
  21: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), ()>>
  22: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::typeck_item_bodies, rustc_query_impl::plumbing::QueryCtxt>
  23: <rustc_session::session::Session>::time::<(), rustc_typeck::check_crate::{closure#7}>
  24: rustc_typeck::check_crate
  25: rustc_interface::passes::analysis
  26: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), core::result::Result<(), rustc_errors::ErrorReported>>>
  27: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::analysis, rustc_query_impl::plumbing::QueryCtxt>
  28: <rustc_interface::passes::QueryContext>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}::{closure#3}, core::result::Result<(), rustc_errors::ErrorReported>>
  29: <rustc_interface::interface::Compiler>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_errors::ErrorReported>>
  30: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorReported>, rustc_interface::interface::create_compiler_and_run<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#1}>
  31: rustc_interface::interface::create_compiler_and_run::<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>
  32: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>
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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.58.0-nightly (e90c5fbbc 2021-11-12) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [typeck] type-checking `main::{constant#0}`
#1 [typeck] type-checking `main::{constant#0}::{closure#0}`
#2 [typeck_item_bodies] type-checking all item bodies
#3 [analysis] running analysis passes on this crate
end of query stack
For more information about this error, try `rustc --explain E0412`.
error: could not compile `playground` due to previous error

[JohnTitor]

Regressed since #76814, cc @jackh726

[JohnTitor]

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

[Badel2]

Another input with a slightly different error message: No bound vars found for "type fn() (hir_id=HirId...

fn main() {
    2: n([u8; 3:fn()])
}

Backtrace

   Compiling playground v0.0.1 (/playground)
error[E0412]: cannot find type `n` in this scope
 --> src/main.rs:2:8
  |
2 |     2: n([u8; 3:fn()])
  |        ^ expecting a type here because of type ascription

error: internal compiler error: compiler/rustc_middle/src/ty/context.rs:2713:21: No bound vars found for "type fn() (hir_id=HirId { owner: DefId(0:3 ~ playground[7419]::main), local_id: 7 })" (HirId { owner: DefId(0:3 ~ playground[7419]::main), local_id: 7 })

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1169:9
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: std::panic::panic_any::<rustc_errors::ExplicitBug>
   2: <rustc_errors::HandlerInner>::bug
   3: <rustc_errors::Handler>::bug
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, ()>
   5: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>
   6: rustc_middle::util::bug::bug_fmt
   7: <rustc_middle::ty::context::TyCtxt>::late_bound_vars
   8: <dyn rustc_typeck::astconv::AstConv>::ty_of_fn
   9: <dyn rustc_typeck::astconv::AstConv>::ast_ty_to_ty_inner
  10: <rustc_typeck::check::fn_ctxt::FnCtxt>::to_ty_saving_user_provided_ty
  11: <rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  12: <rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  13: <rustc_infer::infer::InferCtxtBuilder>::enter::<&rustc_middle::ty::context::TypeckResults, <rustc_typeck::check::inherited::InheritedBuilder>::enter<rustc_typeck::check::typeck_with_fallback<rustc_typeck::check::typeck::{closure#0}>::{closure#1}, &rustc_middle::ty::context::TypeckResults>::{closure#0}>
  14: rustc_typeck::check::typeck
  15: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalDefId, &rustc_middle::ty::context::TypeckResults>>
  16: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck
  17: <rustc_middle::hir::map::Map>::par_body_owners::<rustc_typeck::check::typeck_item_bodies::{closure#0}>
  18: rustc_typeck::check::typeck_item_bodies
  19: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), ()>>
  20: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::typeck_item_bodies, rustc_query_impl::plumbing::QueryCtxt>
  21: <rustc_session::session::Session>::time::<(), rustc_typeck::check_crate::{closure#7}>
  22: rustc_typeck::check_crate
  23: rustc_interface::passes::analysis
  24: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), core::result::Result<(), rustc_errors::ErrorReported>>>
  25: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::analysis, rustc_query_impl::plumbing::QueryCtxt>
  26: <rustc_interface::passes::QueryContext>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}::{closure#3}, core::result::Result<(), rustc_errors::ErrorReported>>
  27: <rustc_interface::interface::Compiler>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_errors::ErrorReported>>
  28: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorReported>, rustc_interface::interface::create_compiler_and_run<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#1}>
  29: rustc_interface::interface::create_compiler_and_run::<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>
  30: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[dwrensha]

searched nightlies: from nightly-2021-01-07 to nightly-2021-12-24
regressed nightly: nightly-2021-07-26
searched commits: from d9aa287 to 9c25eb7
regressed commit: 478126c

bisected with cargo-bisect-rustc v0.6.0

Host triple: x86_64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --start=2021-1-7 --end=2021-12-24 --regress ice 

[dwrensha]

This regressed in #86438. cc @FabianWolff

[Alexendoo]

No longer ICEs since 2643b16