rust-lang / rust-lang/rust

ICE: `Invalid ConstKind for const_to_pat: {const error}`

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C-bug I-ICE S-bug-has-test S-has-mcve T-compiler
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Rust
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Description

Code
impl std::ops::Neg for u128 {}

fn foo(-128..=127: u128) {}

fn main() {}

A mutant of tests/ui/feature-gates/feature-gate-negate-unsigned.rs

Weird. Why both impl and function both needed to ICE reproduction? Maybe u128 makes a bridge between two of them.

Meta

rustc --version --verbose:

rustc 1.93.0-nightly (01867557c 2025-11-12)
binary: rustc
commit-hash: 01867557cd7dbe256a031a7b8e28d05daecd75ab
commit-date: 2025-11-12
host: x86_64-apple-darwin
release: 1.93.0-nightly
LLVM version: 21.1.5
Error output

Command: rustc

error[E0117]: only traits defined in the current crate can be implemented for primitive types
 --> 03.rs:1:1
  |
1 | impl std::ops::Neg for u128 {}
  | ^^^^^^^^^^^^^^^^^^^^^^^----
  |                        |
  |                        `u128` is not defined in the current crate
  |
  = note: impl doesn't have any local type before any uncovered type parameters
  = note: for more information see https://doc.rust-lang.org/reference/items/implementations.html#orphan-rules
  = note: define and implement a trait or new type instead

error: internal compiler error: compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs:52:18: Invalid `ConstKind` for `const_to_pat`: {const error}
 --> 03.rs:3:8
  |
3 | fn foo(-128..=127: u128) {}
  |        ^^^^


thread 'rustc' (278250) panicked at compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs:52:18:
Box<dyn Any>
Backtrace 

thread 'rustc' (278250) panicked at compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs:52:18:
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_errors::DiagCtxtHandle>::span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   3: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   4: 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::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}, !>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: <rustc_mir_build::thir::pattern::PatCtxt>::const_to_pat
   8: <rustc_mir_build::thir::pattern::PatCtxt>::lower_pat_expr
   9: <rustc_mir_build::thir::pattern::PatCtxt>::lower_pattern_range_endpoint
  10: <rustc_mir_build::thir::pattern::PatCtxt>::lower_pattern_range
  11: <rustc_mir_build::thir::pattern::PatCtxt>::lower_pattern
  12: <rustc_mir_build::thir::cx::ThirBuildCx>::pattern_from_hir
  13: rustc_mir_build::thir::cx::thir_body
      [... omitted 2 frames ...]
  14: rustc_mir_build::check_unsafety::check_unsafety
      [... omitted 1 frame ...]
  15: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface::passes::run_required_analyses::{closure#1}::{closure#0}>::{closure#0}
  16: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  17: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>
  18: rustc_interface::interface::run_compiler::<(), 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 `/Users/jb/Library/CloudStorage/Dropbox/Desk/2503_rustc_ice/251109 ice 보고용/rustc-ice-2025-11-13T04_32_09-68741.txt` to your bug report

query stack during panic:
#0 [thir_body] building THIR for `foo`
#1 [check_unsafety] unsafety-checking `foo`
#2 [analysis] running analysis passes on crate `03`
end of query stack
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0117`.

Notes
Duplication Check
  • I searched "compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs" ICE (Github issue page with query), and there are no identical ICE issue there.
  • Closed issue-148542 points to identical ICE location. It's fixed last week.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the ICE with the supplied snippet using the noted nightly compiler, then inspect compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs around line 52. Trace the THIR pattern-lowering path shown in the backtrace, especially const_to_pat and lower_pattern_range_endpoint. Done means the example no longer triggers an internal compiler error while preserving the reported diagnostics.

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
Stale
Clarity
Mostly clear
Newbie friendliness
38/100

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