ICE: `unhandled type: Alias(...)` in `rustc_mir_transform/src/validate.rs` when `[mir_built]`
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- Rust
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Description
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
https://github.com/rust-lang/rust/blob/8fcd4dd08e2ba3e922d917d819ba0be066bdb005/compiler/rustc_mir_transform/src/validate.rs#L1466-L1479 -
#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=onoption.
https://github.com/rust-lang/rust/blob/97bf25c8cf6c7c97c851c6e8bc94fd0824885e6f/compiler/rustc_const_eval/src/transform/validate.rs#L1374
@rustbot label +Zvalidate-mir +F-type_alias_impl_trait +Zpolymorphize
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the hand-reduced example and reproduce it using rustc -Zvalidate-mir. Read compiler/rustc_mir_transform/src/validate.rs around line 1478, then compare the related validation location in compiler/rustc_const_eval/src/transform/validate.rs and issue #125185. Done means the example no longer triggers an internal compiler error under the reported validation and polymorphization paths, with an appropriate regression test.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100