ICE: `unhandled type: Alias(...)` in `rustc_mir_transform/src/validate.rs` when `[mir_built]`

[cushionbadak]

Code

(hand-reduced)

#![feature(type_alias_impl_trait)]
type Bar = impl std::fmt::Display;

use std::path::Path;

struct A {
    pub func: fn(check: Bar, b: Option<&Path>),
}
const MY_A: A = A {
    func: |check, b| {
        if check {
            ()
        } else if let Some(_) = b.and_then(|p| p.parent()) {
            ()
        }
    },
};

fn main() {}

(original)

#![feature(type_alias_impl_trait)]
type Bar = impl std::fmt::Display;

async fn test<const N: crate::Bar>() {}

fn main () {}


#![crate_type = "lib"]
use std::path::Path;
struct A {
    pub func: fn(check: crate::Bar, a: &Path, b: Option<&Path>),
}
const MY_A: A = A {
    func: |check, a, b| {
        if check {
            let _ = ();
        } else if let Some(parent) = b.and_then(|p| p.parent()) {
            let _ = ();
        }
    },
};

Meta

rustc --version --verbose:

rustc 1.81.0-nightly (8fcd4dd08 2024-06-18)
binary: rustc
commit-hash: 8fcd4dd08e2ba3e922d917d819ba0be066bdb005
commit-date: 2024-06-18
host: x86_64-apple-darwin
release: 1.81.0-nightly
LLVM version: 18.1.7

Error output

Command: rustc -Zvalidate-mir

<output>

Backtrace

error: internal compiler error: compiler/rustc_mir_transform/src/validate.rs:1478:30: unhandled type: Alias(Opaque, AliasTy { args: [], def_id: DefId(0:11 ~ r_validate1478_9BFC3853[e0e8]::Bar::{opaque#0}), _use_alias_ty_new_instead: () })

thread 'rustc' panicked at compiler/rustc_mir_transform/src/validate.rs:1478:30:
Box<dyn Any>
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: <rustc_errors::diagnostic::BugAbort as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   2: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   3: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   4: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   5: rustc_middle::util::bug::bug_fmt
   6: <rustc_mir_transform::validate::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_terminator
   7: rustc_mir_transform::validate::validate_types
   8: <rustc_mir_transform::validate::Validator as rustc_middle::mir::MirPass>::run_pass
   9: rustc_mir_transform::pass_manager::run_passes_inner
  10: rustc_mir_transform::mir_built
      [... omitted 1 frame ...]
  11: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>>>
  12: rustc_mir_transform::ffi_unwind_calls::has_ffi_unwind_calls
      [... omitted 1 frame ...]
  13: rustc_mir_transform::mir_promoted
      [... omitted 2 frames ...]
  14: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 16]>>>
  15: rustc_borrowck::mir_borrowck
      [... omitted 1 frame ...]
  16: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>>>
  17: <rustc_borrowck::type_check::TypeChecker>::prove_closure_bounds
  18: <rustc_borrowck::type_check::TypeChecker>::check_rvalue
  19: <rustc_borrowck::type_check::TypeChecker>::typeck_mir
  20: rustc_borrowck::type_check::type_check
  21: rustc_borrowck::nll::compute_regions
  22: rustc_borrowck::do_mir_borrowck
  23: rustc_borrowck::mir_borrowck
      [... omitted 1 frame ...]
  24: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>>>
  25: <rustc_hir_analysis::collect::type_of::opaque::TaitConstraintLocator>::check
  26: rustc_hir_analysis::collect::type_of::type_of_opaque
      [... omitted 1 frame ...]
  27: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>>
  28: rustc_hir_analysis::collect::type_of::type_of
      [... omitted 1 frame ...]
  29: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>>
  30: rustc_hir_analysis::check::check::check_item_type
  31: rustc_hir_analysis::check::wfcheck::check_well_formed
      [... omitted 1 frame ...]
  32: rustc_middle::query::plumbing::query_ensure_error_guaranteed::<rustc_query_system::query::caches::VecCache<rustc_hir::hir_id::OwnerId, rustc_middle::query::erase::Erased<[u8; 1]>>, ()>
  33: rustc_hir_analysis::check::wfcheck::check_mod_type_wf
      [... omitted 1 frame ...]
  34: rustc_hir_analysis::check_crate
  35: rustc_interface::passes::run_required_analyses
  36: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  37: <rustc_interface::queries::QueryResult<&rustc_middle::ty::context::GlobalCtxt>>::enter::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}::{closure#1}::{closure#3}>
  38: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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 `/Volumes/T7/workspace/240615_100chaos_tree_combine_typ/icefiles/rustc-ice-2024-06-19T10_52_49-61021.txt` to your bug report

note: compiler flags: -Z validate-mir

query stack during panic:
#0 [mir_built] building MIR for `MY_A::{closure#0}`
#1 [has_ffi_unwind_calls] checking if `MY_A::{closure#0}` contains FFI-unwind calls
#2 [mir_promoted] promoting constants in MIR for `MY_A::{closure#0}`
#3 [mir_borrowck] borrow-checking `MY_A::{closure#0}`
#4 [mir_borrowck] borrow-checking `MY_A`
#5 [type_of_opaque] computing type of opaque `Bar::{opaque#0}`
#6 [type_of] computing type of `Bar::{opaque#0}`
#7 [check_well_formed] checking that `Bar::{opaque#0}` is well-formed
#8 [check_mod_type_wf] checking that types are well-formed in top-level module
#9 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 1 previous error

Note

• ICE location: compiler/rustc_mir_transform/src/validate.rs#L1478
  

  rust/compiler/rustc_mir_transform/src/validate.rs

  Lines 1466 to 1479 in 8fcd4dd

  	fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
  	match &terminator.kind {
  	TerminatorKind::SwitchInt { targets, discr } => {
  	let switch_ty = discr.ty(&self.body.local_decls, self.tcx);
  	let target_width = self.tcx.sess.target.pointer_width;
  	let size = Size::from_bits(match switch_ty.kind() {
  	ty::Uint(uint) => uint.normalize(target_width).bit_width().unwrap(),
  	ty::Int(int) => int.normalize(target_width).bit_width().unwrap(),
  	ty::Char => 32,
  	ty::Bool => 1,
  	other => bug!("unhandled type: {:?}", other),
  	});

• ICE: unhandled type: {type error} #125185 points to identical ICE-triggering function compiler/rustc_const_eval/src/transform/validate.rs#L1478 in commit-97bf25c8c

  • but shows different query stack,
  • and this also ICEs with rustc -Zpolymorphize=on option.
    

    rust/compiler/rustc_const_eval/src/transform/validate.rs

    Line 1374 in 97bf25c

    other => bug!("unhandled type: {:?}", other),

@rustbot label +Zvalidate-mir +F-type_alias_impl_trait +Zpolymorphize

[rustbot]

Error: Label Zvalidate-mir can only be set by Rust team members

Please file an issue on GitHub at triagebot if there's a problem with this bot, or reach out on #t-infra on Zulip.

[cushionbadak]

@rustbot label +F-type_alias_impl_trait