ICE: `Same capture can't be ByUse and ByValue at the same time`

[cushionbadak]

Code

#![allow(incomplete_features)]
#![feature(ergonomic_clones)]

use std::clone::UseCloned;

#[derive(Clone)]
struct Foo;

impl UseCloned for Foo {}

fn do_not_move_test(x: Foo) -> Foo { async {
    let s = x.use;
    x
} }

fn main() {}

A mutant of tests/ui/ergonomic-clones/dotuse/basic.rs

Meta

rustc --version --verbose:

rustc 1.89.0-nightly (99e7c15e8 2025-06-01)
binary: rustc
commit-hash: 99e7c15e81385b38a8186b51edc4577d5d7b5bdd
commit-date: 2025-06-01
host: aarch64-apple-darwin
release: 1.89.0-nightly
LLVM version: 20.1.5

Error output

command: rustc --edition=2024

--edition=2021 also ICEs

error[E0308]: mismatched types
  --> afidt_3.rs:11:38
   |
11 |   fn do_not_move_test(x: Foo) -> Foo { async {
   |  ________________________________---___^
   | |                                |
   | |                                expected `Foo` because of return type
12 | |     let s = x.use;
13 | |     x
14 | | } }
   | |_^ expected `Foo`, found `async` block
   |
   = note:     expected struct `Foo`
           found `async` block `{async block@afidt_3.rs:11:38: 11:43}`

error: internal compiler error: compiler/rustc_hir_typeck/src/upvar.rs:2431:17: Same capture can't be ByUse and ByValue at the same time


thread 'rustc' panicked at compiler/rustc_hir_typeck/src/upvar.rs:2431:17:
Box<dyn Any>

Backtrace

thread 'rustc' panicked at compiler/rustc_hir_typeck/src/upvar.rs:2431:17:
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_hir_typeck::upvar::determine_capture_info
   7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::compute_min_captures
   8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::analyze_closure
   9: <rustc_hir_typeck::upvar::InferBorrowKindVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  10: rustc_hir_typeck::typeck_with_inspect::{closure#0}
  11: rustc_hir_typeck::typeck
      [... omitted 1 frame ...]
  12: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_hir_analysis::check_crate::{closure#1}>::{closure#0}
  13: rustc_hir_analysis::check_crate
  14: rustc_interface::passes::run_required_analyses
  15: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  16: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>
  17: 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/jisukbyun/workspace/250203 scratch/rustc-ice-2025-06-02T14_11_03-89049.txt` to your bug report

query stack during panic:
#0 [typeck] type-checking `do_not_move_test`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.

Bisects to

searched nightlies: from nightly-2025-01-01 to nightly-2025-06-01
regressed nightly: nightly-2025-03-08
searched commit range: b74da96...f5a1ef7
regressed commit: f5a1ef7

bisected with cargo-bisect-rustc v0.6.9

Host triple: x86_64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --end=2025-06-01 --regress ice --preserve --script rustc -- afidt_3.rs --edition=2024

********************************************************************************
Regression in f5a1ef7121ad661b5a21a1d02941c8064d54ee0b
********************************************************************************

Attempting to search unrolled perf builds
Found commits ["5cf66023", "16414e51", "0b6c069b", "aa349152", "275aad33", "eaf94402"]
installing 5cf660233fcc08fce21f8845d36982b25cb0535c
rust-std-nightly-x86_64-unknown-linux-gnu: 30.69 MB / 30.69 MB [==================================] 100.00 % 12.52 MB/s testing...
RESULT: 5cf660233fcc08fce21f8845d36982b25cb0535c, ===> Script found ICE

Regression in https://github.com/rust-lang-ci/rust/commit/5cf660233fcc08fce21f8845d36982b25cb0535c
The PR introducing the regression in this rollup is #134797: Ergonomic ref counting

Notes

• ICE location: compiler/rustc_hir_typeck/src/upvar.rs Line-2431
  

  rust/compiler/rustc_hir_typeck/src/upvar.rs

  Lines 2425 to 2437 in 99e7c15

  	} else {
  	// We select the CaptureKind which ranks higher based the following priority order:
  	// (ByUse | ByValue) > MutBorrow > UniqueImmBorrow > ImmBorrow
  	match (capture_info_a.capture_kind, capture_info_b.capture_kind) {
  	(ty::UpvarCapture::ByUse, ty::UpvarCapture::ByValue)
  	| (ty::UpvarCapture::ByValue, ty::UpvarCapture::ByUse) => {
  	bug!("Same capture can't be ByUse and ByValue at the same time")
  	}
  	(ty::UpvarCapture::ByValue, ty::UpvarCapture::ByValue)
  	| (ty::UpvarCapture::ByUse, ty::UpvarCapture::ByUse)
  	| (ty::UpvarCapture::ByValue | ty::UpvarCapture::ByUse, ty::UpvarCapture::ByRef(_)) => {
  	capture_info_a
  	}

@rustbot label F-ergonomic_clones

[cushionbadak]

Another ICE code without other errors:

#![allow(incomplete_features)]
#![feature(ergonomic_clones)]

use std::clone::UseCloned;

impl UseCloned for U {}

#[derive(Clone)]
struct S;

#[derive(Clone)]
struct T(S, S);

#[derive(Clone)]
struct U(T, T);

fn foo() {
    let u = U(T(S, S), T(S, S));
    || {
        let _x = u.0.0;
        let _x = ((u).use).0.1;
    };
}

fn main() {}

A mutant of tests/ui/closures/2229_closure_analysis/migrations/precise.rs

Error Output

error: internal compiler error: compiler/rustc_hir_typeck/src/upvar.rs:2431:17: Same capture can't be ByUse and ByValue at the same time


thread 'rustc' panicked at compiler/rustc_hir_typeck/src/upvar.rs:2431:17:
Box<dyn Any>

Backtrace

thread 'rustc' panicked at compiler/rustc_hir_typeck/src/upvar.rs:2431:17:
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_hir_typeck::upvar::determine_capture_info
   7: <alloc::vec::Vec<rustc_middle::ty::closure::CapturedPlace>>::retain::<<rustc_hir_typeck::fn_ctxt::FnCtxt>::compute_min_captures::{closure#0}>::{closure#0}
   8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::compute_min_captures
   9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::analyze_closure
  10: <rustc_hir_typeck::upvar::InferBorrowKindVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  11: <rustc_hir_typeck::upvar::InferBorrowKindVisitor as rustc_hir::intravisit::Visitor>::visit_expr
  12: rustc_hir_typeck::typeck_with_inspect::{closure#0}
  13: rustc_hir_typeck::typeck
      [... omitted 1 frame ...]
  14: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_hir_analysis::check_crate::{closure#1}>::{closure#0}
  15: rustc_hir_analysis::check_crate
  16: rustc_interface::passes::run_required_analyses
  17: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  18: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>
  19: 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/jisukbyun/workspace/250203 scratch/rustc-ice-2025-06-03T10_40_01-97032.txt` to your bug report

query stack during panic:
#0 [typeck] type-checking `foo`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 1 previous error