ICE: we captured CapturedPlace .. but it was not used in the child coroutine?

[matthiaskrgr]

snippet:

fn test(s: &S, t: &i32) {
    async || {
        println!("{}", s.t);
        println!("{}", t);
    };
}

Version information

rustc 1.79.0-nightly (aa6a697a1 2024-04-11)
binary: rustc
commit-hash: aa6a697a1c75b0aa06954136f7641706edadc2be
commit-date: 2024-04-11
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.3

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc --edition=2018

Program output

error[E0412]: cannot find type `S` in this scope
 --> /tmp/icemaker_global_tempdir.zRc1iFaNOZFQ/rustc_testrunner_tmpdir_reporting.OAY0faPDYJlK/mvce.rs:1:13
  |
1 | fn test(s: &S, t: &i32) {
  |             ^ not found in this scope
  |
help: you might be missing a type parameter
  |
1 | fn test<S>(s: &S, t: &i32) {
  |        +++

error[E0658]: async closures are unstable
 --> /tmp/icemaker_global_tempdir.zRc1iFaNOZFQ/rustc_testrunner_tmpdir_reporting.OAY0faPDYJlK/mvce.rs:2:5
  |
2 |     async || {
  |     ^^^^^
  |
  = note: see issue #62290 <https://github.com/rust-lang/rust/issues/62290> for more information
  = help: add `#![feature(async_closure)]` to the crate attributes to enable
  = note: this compiler was built on 2024-04-11; consider upgrading it if it is out of date
  = help: to use an async block, remove the `||`: `async {`

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.zRc1iFaNOZFQ/rustc_testrunner_tmpdir_reporting.OAY0faPDYJlK/mvce.rs:6:2
  |
6 | }
  |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.zRc1iFaNOZFQ/rustc_testrunner_tmpdir_reporting.OAY0faPDYJlK/mvce.rs`

thread 'rustc' panicked at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/compiler/rustc_middle/src/ty/closure.rs:460:13:
we captured CapturedPlace {
    var_ident: s#0,
    place: Place {
        base_ty: ?0t,
        base: Upvar(
            UpvarId(HirId(DefId(0:3 ~ mvce[4541]::test).2);`s`;DefId(0:4 ~ mvce[4541]::test::{closure#0})),
        ),
        projections: [],
    },
    info: CaptureInfo {
        capture_kind_expr_id: None,
        path_expr_id: None,
        capture_kind: ByRef(
            ImmBorrow,
        ),
    },
    mutability: Not,
    region: Some(
        '?48,
    ),
} but it was not used in the child coroutine?
stack backtrace:
   0:     0x7103909d5aa5 - std::backtrace_rs::backtrace::libunwind::trace::he840a2eb6b9d1010
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7103909d5aa5 - std::backtrace_rs::backtrace::trace_unsynchronized::hb5cbb588f6ff9e8a
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7103909d5aa5 - std::sys_common::backtrace::_print_fmt::h2bbcaca7d52fcace
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7103909d5aa5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::ha8b35488b9373e82
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x710390a24f5b - core::fmt::rt::Argument::fmt::h7486f17592b5c408
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/core/src/fmt/rt.rs:142:9
   5:     0x710390a24f5b - core::fmt::write::h38f8b054f2ce97c4
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/core/src/fmt/mod.rs:1153:17
   6:     0x7103909ca6af - std::io::Write::write_fmt::hb5ba4b57b761add2
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/io/mod.rs:1832:15
   7:     0x7103909d587e - std::sys_common::backtrace::_print::habb7d0f73edf4cf4
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7103909d587e - std::sys_common::backtrace::print::hb2b9429afa3b500e
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7103909d8379 - std::panicking::default_hook::{{closure}}::h3f20dac427bbf670
  10:     0x7103909d8095 - std::panicking::default_hook::h3fe8f5c78340bac8
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/panicking.rs:291:9
  11:     0x71038d26a04b - std[36b140a5e3846230]::panicking::update_hook::<alloc[4cfca62bece663de]::boxed::Box<rustc_driver_impl[3824f3c10e5e1962]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7103909d8a7c - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hcd6fabc1cc1ca8f4
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/alloc/src/boxed.rs:2032:9
  13:     0x7103909d8a7c - std::panicking::rust_panic_with_hook::h7c0454bae1c09846
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/panicking.rs:792:13
  14:     0x7103909d8826 - std::panicking::begin_panic_handler::{{closure}}::hb579058774f0d6b4
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/panicking.rs:657:13
  15:     0x7103909d5f69 - std::sys_common::backtrace::__rust_end_short_backtrace::h5415cd9c85ea4680
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7103909d8557 - rust_begin_unwind
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/panicking.rs:645:5
  17:     0x710390a213f6 - core::panicking::panic_fmt::hd279f697292ad797
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/core/src/panicking.rs:72:14
  18:     0x71038d417eb9 - <core[52b5313fa7109ccf]::iter::sources::from_coroutine::FromCoroutine<rustc_middle[84100436d5b064b4]::ty::closure::analyze_coroutine_closure_captures<rustc_middle[84100436d5b064b4]::ty::Ty, core[52b5313fa7109ccf]::iter::adapters::flatten::Flatten<core[52b5313fa7109ccf]::option::IntoIter<core[52b5313fa7109ccf]::iter::adapters::flatten::FlatMap<indexmap[c9872e81d1406d94]::map::iter::Values<rustc_hir[640aa2bf9d482cc]::hir_id::HirId, alloc[4cfca62bece663de]::vec::Vec<rustc_middle[84100436d5b064b4]::ty::closure::CapturedPlace>>, core[52b5313fa7109ccf]::slice::iter::Iter<rustc_middle[84100436d5b064b4]::ty::closure::CapturedPlace>, <rustc_middle[84100436d5b064b4]::ty::typeck_results::TypeckResults>::closure_min_captures_flattened::{closure#0}::{closure#0}>>>, core[52b5313fa7109ccf]::iter::adapters::skip::Skip<core[52b5313fa7109ccf]::iter::adapters::flatten::Flatten<core[52b5313fa7109ccf]::option::IntoIter<core[52b5313fa7109ccf]::iter::adapters::flatten::FlatMap<indexmap[c9872e81d1406d94]::map::iter::Values<rustc_hir[640aa2bf9d482cc]::hir_id::HirId, alloc[4cfca62bece663de]::vec::Vec<rustc_middle[84100436d5b064b4]::ty::closure::CapturedPlace>>, core[52b5313fa7109ccf]::slice::iter::Iter<rustc_middle[84100436d5b064b4]::ty::closure::CapturedPlace>, <rustc_middle[84100436d5b064b4]::ty::typeck_results::TypeckResults>::closure_min_captures_flattened::{closure#0}::{closure#0}>>>>, <rustc_hir_typeck[4fd8731c11591e1f]::fn_ctxt::FnCtxt>::analyze_closure::{closure#0}>::{closure#0}> as core[52b5313fa7109ccf]::iter::traits::iterator::Iterator>::next
  19:     0x71038ef99cb0 - <rustc_hir_typeck[4fd8731c11591e1f]::fn_ctxt::FnCtxt>::analyze_closure
  20:     0x71038b6e7a0b - <rustc_hir_typeck[4fd8731c11591e1f]::upvar::InferBorrowKindVisitor as rustc_hir[640aa2bf9d482cc]::intravisit::Visitor>::visit_expr
  21:     0x71038e9b97c4 - <rustc_hir_typeck[4fd8731c11591e1f]::upvar::InferBorrowKindVisitor as rustc_hir[640aa2bf9d482cc]::intravisit::Visitor>::visit_block
  22:     0x71038e9bba9e - rustc_hir_typeck[4fd8731c11591e1f]::typeck
  23:     0x71038e9bb189 - rustc_query_impl[e4745a1b0909859d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e4745a1b0909859d]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[84100436d5b064b4]::query::erase::Erased<[u8; 8usize]>>
  24:     0x71038e9d3df1 - rustc_query_system[d932b23f04408b52]::query::plumbing::try_execute_query::<rustc_query_impl[e4745a1b0909859d]::DynamicConfig<rustc_query_system[d932b23f04408b52]::query::caches::VecCache<rustc_span[e30230202ad71cc6]::def_id::LocalDefId, rustc_middle[84100436d5b064b4]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[e4745a1b0909859d]::plumbing::QueryCtxt, false>
  25:     0x71038e9d270c - rustc_query_impl[e4745a1b0909859d]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  26:     0x71038e9d22d4 - <rustc_middle[84100436d5b064b4]::hir::map::Map>::par_body_owners::<rustc_hir_analysis[65fee01cac67d305]::check_crate::{closure#4}>::{closure#0}
  27:     0x71038e9d0fa0 - rustc_hir_analysis[65fee01cac67d305]::check_crate
  28:     0x71038eb5fb96 - rustc_interface[98672636c24166f2]::passes::analysis
  29:     0x71038eb5f6dd - rustc_query_impl[e4745a1b0909859d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e4745a1b0909859d]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[84100436d5b064b4]::query::erase::Erased<[u8; 1usize]>>
  30:     0x71038f44b5e5 - rustc_query_system[d932b23f04408b52]::query::plumbing::try_execute_query::<rustc_query_impl[e4745a1b0909859d]::DynamicConfig<rustc_query_system[d932b23f04408b52]::query::caches::SingleCache<rustc_middle[84100436d5b064b4]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[e4745a1b0909859d]::plumbing::QueryCtxt, false>
  31:     0x71038f44b349 - rustc_query_impl[e4745a1b0909859d]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  32:     0x71038f2e6d93 - rustc_interface[98672636c24166f2]::interface::run_compiler::<core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>, rustc_driver_impl[3824f3c10e5e1962]::run_compiler::{closure#0}>::{closure#0}
  33:     0x71038f3bf45d - std[36b140a5e3846230]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[98672636c24166f2]::util::run_in_thread_with_globals<rustc_interface[98672636c24166f2]::util::run_in_thread_pool_with_globals<rustc_interface[98672636c24166f2]::interface::run_compiler<core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>, rustc_driver_impl[3824f3c10e5e1962]::run_compiler::{closure#0}>::{closure#0}, core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>>::{closure#0}, core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>>
  34:     0x71038f3bf26a - <<std[36b140a5e3846230]::thread::Builder>::spawn_unchecked_<rustc_interface[98672636c24166f2]::util::run_in_thread_with_globals<rustc_interface[98672636c24166f2]::util::run_in_thread_pool_with_globals<rustc_interface[98672636c24166f2]::interface::run_compiler<core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>, rustc_driver_impl[3824f3c10e5e1962]::run_compiler::{closure#0}>::{closure#0}, core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>>::{closure#0}, core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[52b5313fa7109ccf]::result::Result<(), rustc_span[e30230202ad71cc6]::ErrorGuaranteed>>::{closure#1} as core[52b5313fa7109ccf]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  35:     0x7103909e297b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h64aa0f357081d070
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/alloc/src/boxed.rs:2018:9
  36:     0x7103909e297b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h1899233896b31bde
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/alloc/src/boxed.rs:2018:9
  37:     0x7103909e297b - std::sys::pal::unix::thread::Thread::new::thread_start::he3bcf1faa75389b7
                               at /rustc/aa6a697a1c75b0aa06954136f7641706edadc2be/library/std/src/sys/pal/unix/thread.rs:108:17
  38:     0x71039078055a - <unknown>
  39:     0x7103907fda3c - <unknown>
  40:                0x0 - <unknown>

error: 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: please make sure that you have updated to the latest nightly

note: rustc 1.79.0-nightly (aa6a697a1 2024-04-11) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z dump-mir-dir=dir

query stack during panic:
#0 [typeck] type-checking `test`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 3 previous errors

Some errors have detailed explanations: E0412, E0601, E0658.
For more information about an error, try `rustc --explain E0412`.

[matthiaskrgr]

@compiler-errors probably also caused by #123660 ?

[compiler-errors]

yep ill put up a fix in a few