ICE: deref projection of non-dereferenceable ty with feature(type_alias_impl_trait) and polymorphization

[Naserume]

Code

#![feature(type_alias_impl_trait)]
type Two<'a, 'b> = impl std::fmt::Debug;

fn set(x: &mut isize) -> isize {
    *x
}

fn d(x: Two) {
    let c1 = || set(x);
    c1;
}

fn main() {
}

Meta

rustc --version --verbose:

rustc 1.81.0-nightly (bcf94dec5 2024-06-23)
binary: rustc
commit-hash: bcf94dec5ba6838e435902120c0384c360126a26
commit-date: 2024-06-23
host: x86_64-apple-darwin
release: 1.81.0-nightly
LLVM version: 18.1.7

Command
/home/user/.cargo/bin/rustc ./E7BC0.rs -Zpolymorphize=on -Zinline-mir=yes

Error output

error[E0792]: expected generic lifetime parameter, found `'_`
 --> ./E7BC0.rs:9:17
  |
2 | type Two<'a, 'b> = impl std::fmt::Debug;
  |          -- this generic parameter must be used with a generic lifetime parameter
...
9 |     let c1 = || set(x);
  |                 ^^^^^^

Backtrace

error: internal compiler error: compiler/rustc_middle/src/mir/tcx.rs:83:21: deref projection of non-dereferenceable ty PlaceTy { ty: {type error}, variant_index: None }

thread 'rustc' panicked at compiler/rustc_middle/src/mir/tcx.rs:83:21:
Box<dyn Any>
stack backtrace:
   0:        0x10bae6b43 - <std::sys::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::he71f7af0ddafc64d
   1:        0x10bb3225b - core::fmt::write::h30d0e266faff29b6
   2:        0x10badcace - std::io::Write::write_fmt::he666ca78eb4b8406
   3:        0x10bae6931 - std::sys::backtrace::print::h22721f9ab9a2749a
   4:        0x10bae9709 - std::panicking::default_hook::{{closure}}::h145e29ed875d8021
   5:        0x10bae948a - std::panicking::default_hook::h5d437c7e6bf0e3b5
   6:        0x114d8147c - std[8efa578c02603ef9]::panicking::update_hook::<alloc[135510a28be92df]::boxed::Box<rustc_driver_impl[63f2171535a6fe49]::install_ice_hook::{closure#0}>>::{closure#0}
   7:        0x10baea326 - std::panicking::rust_panic_with_hook::h6889093a56e48d04
   8:        0x114df0337 - std[8efa578c02603ef9]::panicking::begin_panic::<rustc_errors[8995f93e9c4bcc9a]::ExplicitBug>::{closure#0}
   9:        0x114ddc949 - std[8efa578c02603ef9]::sys::backtrace::__rust_end_short_backtrace::<std[8efa578c02603ef9]::panicking::begin_panic<rustc_errors[8995f93e9c4bcc9a]::ExplicitBug>::{closure#0}, !>
  10:        0x1197e2f09 - std[8efa578c02603ef9]::panicking::begin_panic::<rustc_errors[8995f93e9c4bcc9a]::ExplicitBug>
  11:        0x114e02276 - <rustc_errors[8995f93e9c4bcc9a]::diagnostic::BugAbort as rustc_errors[8995f93e9c4bcc9a]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:        0x115a9c95e - rustc_middle[4384e439927f71dd]::util::bug::opt_span_bug_fmt::<rustc_span[aed5394308446158]::span_encoding::Span>::{closure#0}
  13:        0x115a522b7 - rustc_middle[4384e439927f71dd]::ty::context::tls::with_opt::<rustc_middle[4384e439927f71dd]::util::bug::opt_span_bug_fmt<rustc_span[aed5394308446158]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  14:        0x115a51d75 - rustc_middle[4384e439927f71dd]::ty::context::tls::with_context_opt::<rustc_middle[4384e439927f71dd]::ty::context::tls::with_opt<rustc_middle[4384e439927f71dd]::util::bug::opt_span_bug_fmt<rustc_span[aed5394308446158]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  15:        0x1198a57eb - rustc_middle[4384e439927f71dd]::util::bug::bug_fmt
  16:        0x115a118af - <rustc_middle[4384e439927f71dd]::mir::tcx::PlaceTy>::projection_ty
  17:        0x115dfe1b0 - <rustc_mir_transform[6fada3a7f62d9c6e]::remove_zsts::Replacer as rustc_middle[4384e439927f71dd]::mir::visit::MutVisitor>::visit_operand
  18:        0x115dfdbf1 - <rustc_mir_transform[6fada3a7f62d9c6e]::remove_zsts::RemoveZsts as rustc_middle[4384e439927f71dd]::mir::MirPass>::run_pass
  19:        0x115d76f44 - rustc_mir_transform[6fada3a7f62d9c6e]::pass_manager::run_passes_inner
  20:        0x115e2a633 - rustc_mir_transform[6fada3a7f62d9c6e]::optimized_mir
  21:        0x11641c908 - rustc_query_impl[a24e9023943e74ab]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a24e9023943e74ab]::query_impl::optimized_mir::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4384e439927f71dd]::query::erase::Erased<[u8; 8usize]>>
  22:        0x1161f724f - rustc_query_system[30bd0146b5104221]::query::plumbing::try_execute_query::<rustc_query_impl[a24e9023943e74ab]::DynamicConfig<rustc_query_system[30bd0146b5104221]::query::caches::DefIdCache<rustc_middle[4384e439927f71dd]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[a24e9023943e74ab]::plumbing::QueryCtxt, false>
  23:        0x116435849 - rustc_query_impl[a24e9023943e74ab]::query_impl::optimized_mir::get_query_non_incr::__rust_end_short_backtrace
  24:        0x115e5faef - rustc_middle[4384e439927f71dd]::query::plumbing::query_get_at::<rustc_query_system[30bd0146b5104221]::query::caches::DefIdCache<rustc_middle[4384e439927f71dd]::query::erase::Erased<[u8; 8usize]>>>
  25:        0x115e9bf18 - rustc_monomorphize[7e44dc73c1b07443]::polymorphize::unused_generic_params
  26:        0x116420333 - rustc_query_impl[a24e9023943e74ab]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a24e9023943e74ab]::query_impl::unused_generic_params::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4384e439927f71dd]::query::erase::Erased<[u8; 4usize]>>
  27:        0x1163d4c0f - <rustc_query_impl[a24e9023943e74ab]::query_impl::unused_generic_params::dynamic_query::{closure#2} as core[9412a59d758dca42]::ops::function::FnOnce<(rustc_middle[4384e439927f71dd]::ty::context::TyCtxt, rustc_middle[4384e439927f71dd]::ty::instance::InstanceKind)>>::call_once
  28:        0x11625c12c - rustc_query_system[30bd0146b5104221]::query::plumbing::try_execute_query::<rustc_query_impl[a24e9023943e74ab]::DynamicConfig<rustc_query_system[30bd0146b5104221]::query::caches::DefaultCache<rustc_middle[4384e439927f71dd]::ty::instance::InstanceKind, rustc_middle[4384e439927f71dd]::query::erase::Erased<[u8; 4usize]>>, false, false, false>, rustc_query_impl[a24e9023943e74ab]::plumbing::QueryCtxt, false>
  29:        0x11647a486 - rustc_query_impl[a24e9023943e74ab]::query_impl::unused_generic_params::get_query_non_incr::__rust_end_short_backtrace
  30:        0x1156dac81 - rustc_interface[73216d77aad0c3a5]::passes::run_required_analyses
  31:        0x1156dccb3 - rustc_interface[73216d77aad0c3a5]::passes::analysis
  32:        0x116422dec - rustc_query_impl[a24e9023943e74ab]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[a24e9023943e74ab]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4384e439927f71dd]::query::erase::Erased<[u8; 1usize]>>
  33:        0x11620249e - rustc_query_system[30bd0146b5104221]::query::plumbing::try_execute_query::<rustc_query_impl[a24e9023943e74ab]::DynamicConfig<rustc_query_system[30bd0146b5104221]::query::caches::SingleCache<rustc_middle[4384e439927f71dd]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[a24e9023943e74ab]::plumbing::QueryCtxt, false>
  34:        0x11642d307 - rustc_query_impl[a24e9023943e74ab]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  35:        0x114d258d7 - <rustc_interface[73216d77aad0c3a5]::queries::QueryResult<&rustc_middle[4384e439927f71dd]::ty::context::GlobalCtxt>>::enter::<core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>, rustc_driver_impl[63f2171535a6fe49]::run_compiler::{closure#0}::{closure#1}::{closure#3}>
  36:        0x114d7fc94 - rustc_interface[73216d77aad0c3a5]::interface::run_compiler::<core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>, rustc_driver_impl[63f2171535a6fe49]::run_compiler::{closure#0}>::{closure#1}
  37:        0x114d6ec91 - std[8efa578c02603ef9]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[73216d77aad0c3a5]::util::run_in_thread_with_globals<rustc_interface[73216d77aad0c3a5]::util::run_in_thread_pool_with_globals<rustc_interface[73216d77aad0c3a5]::interface::run_compiler<core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>, rustc_driver_impl[63f2171535a6fe49]::run_compiler::{closure#0}>::{closure#1}, core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>>::{closure#0}, core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>>
  38:        0x114d8a3a6 - <<std[8efa578c02603ef9]::thread::Builder>::spawn_unchecked_<rustc_interface[73216d77aad0c3a5]::util::run_in_thread_with_globals<rustc_interface[73216d77aad0c3a5]::util::run_in_thread_pool_with_globals<rustc_interface[73216d77aad0c3a5]::interface::run_compiler<core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>, rustc_driver_impl[63f2171535a6fe49]::run_compiler::{closure#0}>::{closure#1}, core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>>::{closure#0}, core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[9412a59d758dca42]::result::Result<(), rustc_span[aed5394308446158]::ErrorGuaranteed>>::{closure#2} as core[9412a59d758dca42]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  39:        0x10baf352b - std::sys::pal::unix::thread::Thread::new::thread_start::h68d49fa26efc1659
  40:     0x7ff801f5318b - __pthread_start

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/Users/Documents/rustc-ice-27151.txt` to your bug report

note: compiler flags: -Z polymorphize=on -Z inline-mir=yes

query stack during panic:
#0 [optimized_mir] optimizing MIR for `d::{closure#0}`
#1 [unused_generic_params] determining which generic parameters are unused by `d::{closure#0}`
end of query stack
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0792`.

[lqd]

The -Zpolymorphize=on flag is load-bearing here not the TAIT one. Anyways, bisects to #120550.