ICE: compiler/rustc_typeck/src/hir_wf_check.rs:133:29: Unexpected TraitItem

[chengniansun]

Code

trait u32 {
    const CONST: u32;
}

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 `u32` should have an upper camel case name
 --> mutant.rs:1:7
  |
1 | trait u32 {
  |       ^^^ help: convert the identifier to upper camel case (notice the capitalization): `U32`
  |
  = note: `#[warn(non_camel_case_types)]` on by default

warning: trait objects without an explicit `dyn` are deprecated
 --> mutant.rs:2:18
  |
2 |     const CONST: u32;
  |                  ^^^ help: use `dyn`: `dyn 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: associated item referring to unboxed trait object for its own trait
 --> mutant.rs:2:18
  |
1 | trait u32 {
  |       --- in this trait
2 |     const CONST: u32;
  |                  ^^^
  |
help: you might have meant to use `Self` to refer to the implementing type
  |
2 |     const CONST: Self;
  |                  ^^^^

error: internal compiler error: compiler/rustc_typeck/src/hir_wf_check.rs:133:29: Unexpected TraitItem Const(Ty { hir_id: HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 3 }, kind: TraitObject([PolyTraitRef { bound_generic_params: [], trait_ref: TraitRef { path: Path { span: mutant.rs:2:18: 2:21 (#0), res: Def(Trait, DefId(0:3 ~ mutant[d0c6]::u32)), segments: [PathSegment { ident: u32#0, hir_id: Some(HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 2 }), res: Some(Def(Trait, DefId(0:3 ~ mutant[d0c6]::u32))), args: None, infer_args: false }] }, hir_ref_id: HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 1 } }, span: mutant.rs:2:18: 2:21 (#0) }], lifetime(HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 4 }: ), None), span: mutant.rs:2:18: 2:21 (#0) }, None)

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1034:9
note: run with `RUST_BACKTRACE=1` environment variable to display a 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 1.56.0-nightly (9c25eb7aa 2021-07-25) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type staticlib

query stack during panic:
#0 [diagnostic_hir_wf_check] performing HIR wf-checking for predicate Binder(ObjectSafe(DefId(0:3 ~ mutant[d0c6]::u32)), []) at item Ty(DefId(0:4 ~ mutant[d0c6]::u32::CONST))
#1 [check_trait_item_well_formed] checking that `u32::CONST` is well-formed
end of query stack
error: aborting due to 2 previous errors; 2 warnings emitted

Backtrace

warning: trait `u32` should have an upper camel case name
 --> mutant.rs:1:7
  |
1 | trait u32 {
  |       ^^^ help: convert the identifier to upper camel case (notice the capitalization): `U32`
  |
  = note: `#[warn(non_camel_case_types)]` on by default

warning: trait objects without an explicit `dyn` are deprecated
 --> mutant.rs:2:18
  |
2 |     const CONST: u32;
  |                  ^^^ help: use `dyn`: `dyn 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: associated item referring to unboxed trait object for its own trait
 --> mutant.rs:2:18
  |
1 | trait u32 {
  |       --- in this trait
2 |     const CONST: u32;
  |                  ^^^
  |
help: you might have meant to use `Self` to refer to the implementing type
  |
2 |     const CONST: Self;
  |                  ^^^^

error: internal compiler error: compiler/rustc_typeck/src/hir_wf_check.rs:133:29: Unexpected TraitItem Const(Ty { hir_id: HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 3 }, kind: TraitObject([PolyTraitRef { bound_generic_params: [], trait_ref: TraitRef { path: Path { span: mutant.rs:2:18: 2:21 (#0), res: Def(Trait, DefId(0:3 ~ mutant[d0c6]::u32)), segments: [PathSegment { ident: u32#0, hir_id: Some(HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 2 }), res: Some(Def(Trait, DefId(0:3 ~ mutant[d0c6]::u32))), args: None, infer_args: false }] }, hir_ref_id: HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 1 } }, span: mutant.rs:2:18: 2:21 (#0) }], lifetime(HirId { owner: DefId(0:4 ~ mutant[d0c6]::u32::CONST), local_id: 4 }: ), None), span: mutant.rs:2:18: 2:21 (#0) }, None)

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1034:9
stack backtrace:
   0: std::panicking::begin_panic
   1: std::panic::panic_any
   2: rustc_errors::HandlerInner::bug
   3: rustc_errors::Handler::bug
   4: rustc_middle::ty::context::tls::with_opt
   5: rustc_middle::util::bug::opt_span_bug_fmt
   6: rustc_middle::util::bug::bug_fmt
   7: rustc_typeck::hir_wf_check::diagnostic_hir_wf_check
   8: rustc_query_system::query::plumbing::get_query_impl
   9: rustc_query_system::query::plumbing::get_query
  10: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::error_reporting::InferCtxtExt>::report_selection_error
  11: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::error_reporting::InferCtxtPrivExt>::report_fulfillment_error
  12: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::error_reporting::InferCtxtExt>::report_fulfillment_errors
  13: rustc_typeck::check::fn_ctxt::_impl::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::select_all_obligations_or_error
  14: rustc_infer::infer::InferCtxtBuilder::enter
  15: rustc_typeck::check::wfcheck::check_associated_item
  16: rustc_typeck::check::wfcheck::check_trait_item
  17: rustc_query_system::query::plumbing::get_query_impl
  18: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_trait_item_well_formed
  19: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::intravisit::Visitor>::visit_trait_item
  20: std::panicking::try
  21: rustc_data_structures::sync::par_for_each_in
  22: rustc_session::session::Session::track_errors
  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.

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

note: compiler flags: --crate-type staticlib

query stack during panic:
#0 [diagnostic_hir_wf_check] performing HIR wf-checking for predicate Binder(ObjectSafe(DefId(0:3 ~ mutant[d0c6]::u32)), []) at item Ty(DefId(0:4 ~ mutant[d0c6]::u32::CONST))
#1 [check_trait_item_well_formed] checking that `u32::CONST` is well-formed
#2 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors; 2 warnings emitted

[hellow554]

I used this to make some warnings/errors go away:

#[allow(non_camel_case_types)]
trait u32 {
    const CONST: Box<dyn u32>;
}

fn main() {}

Regressed in 7c89e38

cc #87265 @Aaron1011

@rustbot modify labels: regression-from-stable-to-nightly