TAIT ICE "extracting field of non-tuple non-adt"

[jruderman]

Found with a modified fuzz-rustc

Code

#![feature(type_alias_impl_trait)]

fn main() {
    type T = impl Sized;
    let (_a, _b): T = (1u32, 2u32);
}

Error output

error: internal compiler error: compiler/rustc_middle/src/mir/tcx.rs:49:18: extracting field of non-tuple non-adt: PlaceTy { ty: main::T, variant_index: None }

Backtrace

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/a00f8ba7fcac1b27341679c51bf5a3271fa82df3/compiler/rustc_errors/src/lib.rs:1555:9
stack backtrace:
   0:        0x106fb8f22 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc8a49f87ce17062a
   1:        0x10701785a - core::fmt::write::h8a1a7abc727fe6d0
   2:        0x106fab2ec - std::io::Write::write_fmt::h784a2d3ee2ee8639
   3:        0x106fb8cea - std::sys_common::backtrace::print::hb4003780820818b1
   4:        0x106fbc016 - std::panicking::default_hook::{{closure}}::ha4bb64ed2ba8f281
   5:        0x106fbbd67 - std::panicking::default_hook::haa41a49d8ba42d3b
   6:        0x115b619bd - rustc_driver[3dbfeae94bbb450c]::DEFAULT_HOOK::{closure#0}::{closure#0}
   7:        0x106fbc7fd - std::panicking::rust_panic_with_hook::h0ec6182f72894cd1
   8:        0x11a316d77 - std[b7fc25f664aa2c42]::panicking::begin_panic::<rustc_errors[3e76822466e0ccc2]::ExplicitBug>::{closure#0}
   9:        0x11a3165f9 - std[b7fc25f664aa2c42]::sys_common::backtrace::__rust_end_short_backtrace::<std[b7fc25f664aa2c42]::panicking::begin_panic<rustc_errors[3e76822466e0ccc2]::ExplicitBug>::{closure#0}, !>
  10:        0x11a91bff9 - std[b7fc25f664aa2c42]::panicking::begin_panic::<rustc_errors[3e76822466e0ccc2]::ExplicitBug>
  11:        0x11a316589 - std[b7fc25f664aa2c42]::panic::panic_any::<rustc_errors[3e76822466e0ccc2]::ExplicitBug>
  12:        0x11a313ecd - <rustc_errors[3e76822466e0ccc2]::HandlerInner>::bug::<&alloc[f3b087a993ab1fcd]::string::String>
  13:        0x11a313997 - <rustc_errors[3e76822466e0ccc2]::Handler>::bug::<&alloc[f3b087a993ab1fcd]::string::String>
  14:        0x11a3c2e52 - rustc_middle[e2305deeabdd0cca]::ty::context::tls::with_context_opt::<rustc_middle[e2305deeabdd0cca]::ty::context::tls::with_opt<rustc_middle[e2305deeabdd0cca]::util::bug::opt_span_bug_fmt<rustc_span[663101514bc5927d]::span_encoding::Span>::{closure#0}, ()>::{closure#0}, ()>
  15:        0x11a3c3251 - rustc_middle[e2305deeabdd0cca]::util::bug::opt_span_bug_fmt::<rustc_span[663101514bc5927d]::span_encoding::Span>
  16:        0x11a91d9ae - rustc_middle[e2305deeabdd0cca]::util::bug::bug_fmt
  17:        0x11a325665 - <rustc_middle[e2305deeabdd0cca]::mir::tcx::PlaceTy>::field_ty
  18:        0x118ecd151 - <rustc_middle[e2305deeabdd0cca]::mir::tcx::PlaceTy>::projection_ty_core::<(), (), <rustc_borrowck[d2407f5e24f18162]::type_check::TypeChecker>::relate_type_and_user_type::{closure#0}, <rustc_borrowck[d2407f5e24f18162]::type_check::TypeChecker>::relate_type_and_user_type::{closure#1}>
  19:        0x118d8a1ad - <rustc_borrowck[d2407f5e24f18162]::type_check::TypeChecker>::relate_type_and_user_type
  20:        0x118d84e84 - <rustc_borrowck[d2407f5e24f18162]::type_check::TypeVerifier as rustc_middle[e2305deeabdd0cca]::mir::visit::Visitor>::visit_local_decl
  21:        0x118d85bd3 - <rustc_borrowck[d2407f5e24f18162]::type_check::TypeVerifier as rustc_middle[e2305deeabdd0cca]::mir::visit::Visitor>::visit_body
  22:        0x118d7ee38 - rustc_borrowck[d2407f5e24f18162]::type_check::type_check
  23:        0x118e8e8f2 - rustc_borrowck[d2407f5e24f18162]::nll::compute_regions
  24:        0x118ec9c90 - rustc_borrowck[d2407f5e24f18162]::do_mir_borrowck
  25:        0x118ebb75d - rustc_borrowck[d2407f5e24f18162]::mir_borrowck
  26:        0x118e9c505 - <rustc_borrowck[d2407f5e24f18162]::provide::{closure#0} as core[67cd3202410ff936]::ops::function::FnOnce<(rustc_middle[e2305deeabdd0cca]::ty::context::TyCtxt, rustc_span[663101514bc5927d]::def_id::LocalDefId)>>::call_once
  27:        0x119345c19 - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::try_execute_query::<rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt, rustc_query_system[3b5dd79aa171f2d6]::query::caches::DefaultCache<rustc_span[663101514bc5927d]::def_id::LocalDefId, &rustc_middle[e2305deeabdd0cca]::mir::query::BorrowCheckResult>>
  28:        0x11942dad3 - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::get_query::<rustc_query_impl[b50f402e55213e8a]::queries::mir_borrowck, rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt>
  29:        0x1185a3ba4 - <rustc_hir_analysis[34bd11cda90a81cf]::collect::type_of::find_opaque_ty_constraints_for_tait::ConstraintLocator>::check
  30:        0x1185a2fb1 - rustc_hir_analysis[34bd11cda90a81cf]::collect::type_of::find_opaque_ty_constraints_for_tait
  31:        0x11859a846 - rustc_hir_analysis[34bd11cda90a81cf]::collect::type_of::type_of
  32:        0x119369df5 - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::try_execute_query::<rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt, rustc_query_system[3b5dd79aa171f2d6]::query::caches::DefaultCache<rustc_span[663101514bc5927d]::def_id::DefId, rustc_middle[e2305deeabdd0cca]::ty::Ty>>
  33:        0x119441184 - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::get_query::<rustc_query_impl[b50f402e55213e8a]::queries::type_of, rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt>
  34:        0x11854cb76 - rustc_hir_analysis[34bd11cda90a81cf]::check::check::check_item_type
  35:        0x1185535ee - rustc_hir_analysis[34bd11cda90a81cf]::check::check::check_mod_item_types
  36:        0x119349295 - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::try_execute_query::<rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt, rustc_query_system[3b5dd79aa171f2d6]::query::caches::DefaultCache<rustc_span[663101514bc5927d]::def_id::LocalDefId, ()>>
  37:        0x1194371a5 - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::get_query::<rustc_query_impl[b50f402e55213e8a]::queries::check_mod_item_types, rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt>
  38:        0x11857bb58 - <rustc_middle[e2305deeabdd0cca]::hir::map::Map>::for_each_module::<rustc_hir_analysis[34bd11cda90a81cf]::check_crate::{closure#6}::{closure#0}>
  39:        0x118569f79 - <rustc_session[e61d3bba1e132503]::session::Session>::time::<(), rustc_hir_analysis[34bd11cda90a81cf]::check_crate::{closure#6}>
  40:        0x11863cecf - rustc_hir_analysis[34bd11cda90a81cf]::check_crate
  41:        0x115c2481a - rustc_interface[57c9fce0e0c2ba2]::passes::analysis
  42:        0x1193c6ffc - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::try_execute_query::<rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt, rustc_query_system[3b5dd79aa171f2d6]::query::caches::DefaultCache<(), core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>>>
  43:        0x119441299 - rustc_query_system[3b5dd79aa171f2d6]::query::plumbing::get_query::<rustc_query_impl[b50f402e55213e8a]::queries::analysis, rustc_query_impl[b50f402e55213e8a]::plumbing::QueryCtxt>
  44:        0x115af0dd6 - <rustc_interface[57c9fce0e0c2ba2]::passes::QueryContext>::enter::<rustc_driver[3dbfeae94bbb450c]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>>
  45:        0x115b34ecd - rustc_span[663101514bc5927d]::with_source_map::<core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>, rustc_interface[57c9fce0e0c2ba2]::interface::run_compiler<core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>, rustc_driver[3dbfeae94bbb450c]::run_compiler::{closure#1}>::{closure#0}::{closure#1}>
  46:        0x115b24f2c - <scoped_tls[6bbd84b04dbf1568]::ScopedKey<rustc_span[663101514bc5927d]::SessionGlobals>>::set::<rustc_interface[57c9fce0e0c2ba2]::interface::run_compiler<core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>, rustc_driver[3dbfeae94bbb450c]::run_compiler::{closure#1}>::{closure#0}, core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>>
  47:        0x115af431a - std[b7fc25f664aa2c42]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[57c9fce0e0c2ba2]::util::run_in_thread_pool_with_globals<rustc_interface[57c9fce0e0c2ba2]::interface::run_compiler<core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>, rustc_driver[3dbfeae94bbb450c]::run_compiler::{closure#1}>::{closure#0}, core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>>
  48:        0x115ada3ab - <<std[b7fc25f664aa2c42]::thread::Builder>::spawn_unchecked_<rustc_interface[57c9fce0e0c2ba2]::util::run_in_thread_pool_with_globals<rustc_interface[57c9fce0e0c2ba2]::interface::run_compiler<core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>, rustc_driver[3dbfeae94bbb450c]::run_compiler::{closure#1}>::{closure#0}, core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[67cd3202410ff936]::result::Result<(), rustc_errors[3e76822466e0ccc2]::ErrorGuaranteed>>::{closure#1} as core[67cd3202410ff936]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  49:        0x106fc5bb7 - std::sys::unix::thread::Thread::new::thread_start::h0a480c6421a176eb
  50:     0x7ff80d84d4e1 - __pthread_start

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 1.67.0-nightly (a00f8ba7f 2022-11-15) running on x86_64-apple-darwin

query stack during panic:
#0 [mir_borrowck] borrow-checking `main`
#1 [type_of] computing type of `main::T::{opaque#0}`
#2 [check_mod_item_types] checking item types in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

Regression

Regression in nightly-2022-05-23, perhaps from #96515

Version

rustc 1.67.0-nightly (a00f8ba7f 2022-11-15)
binary: rustc
commit-hash: a00f8ba7fcac1b27341679c51bf5a3271fa82df3
commit-date: 2022-11-15
host: x86_64-apple-darwin
release: 1.67.0-nightly
LLVM version: 15.0.4

@rustbot label +F-type_alias_impl_trait