ICE:gather_locals

[sososopy]

It is a similar issue to #140730 and might be a repetitive one of its problems

Code

fn main() {
    let mut num: &i16;
    num += ()?;
}

Meta

rustc --version --verbose:

rustc 1.88.0-nightly (e9f8103f9 2025-05-07)
binary: rustc
commit-hash: e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d
commit-date: 2025-05-07
host: x86_64-pc-windows-msvc
release: 1.88.0-nightly
LLVM version: 20.1.4

Error output

error[E0277]: the `?` operator can only be applied to values that implement `Try`
    |
292 |     num += ()?;
    |            ^^^ the `?` operator cannot be applied to type `()`
    |
    = help: the trait `Try` is not implemented for `()`

error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
    |
290 | fn main() {
    | --------- this function should return `Result` or `Option` to accept `?`
291 |     let mut num: &i16;
292 |     num += ()?;
    |              ^ cannot use the `?` operator in a function that returns `()`

Backtrace

thread 'rustc' panicked at compiler\rustc_hir_typeck\src\gather_locals.rs:112:17:
assertion `left == right` failed
  left: Some(?12t)
 right: None
stack backtrace:
   0:     0x7fffb4efc702 - std::backtrace_rs::backtrace::win64::trace
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\..\..\backtrace\src\backtrace\win64.rs:85
   1:     0x7fffb4efc702 - std::backtrace_rs::backtrace::trace_unsynchronized
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66
   2:     0x7fffb4efc702 - std::sys::backtrace::_print_fmt
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\sys\backtrace.rs:66
   3:     0x7fffb4efc702 - std::sys::backtrace::impl$0::print::impl$0::fmt
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\sys\backtrace.rs:39
   4:     0x7fffb4f2eecb - core::fmt::rt::Argument::fmt
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\core\src\fmt\rt.rs:181
   5:     0x7fffb4f2eecb - core::fmt::write
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\core\src\fmt\mod.rs:1446
   6:     0x7fffb4ef26d7 - std::io::default_write_fmt
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\io\mod.rs:639
   7:     0x7fffb4ef26d7 - std::io::Write::write_fmt<std::sys::stdio::windows::Stderr>
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\io\mod.rs:1914
   8:     0x7fffb4efc545 - std::sys::backtrace::BacktraceLock::print
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\sys\backtrace.rs:42
   9:     0x7fffb4f0219a - std::panicking::default_hook::closure$0
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\panicking.rs:300
  10:     0x7fffb4f01f30 - std::panicking::default_hook
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\panicking.rs:327
  11:     0x7fffb6618b39 - core[12cfcfafe2bb19e]::slice::sort::unstable::heapsort::heapsort::<((rustc_lint_defs[e43e066ad2f79cd0]::Level, &str), usize), <((rustc_lint_defs[e43e066ad2f79cd0]::Level, &str), usize) as 
core[12cfcfafe2bb19e]::cmp::PartialOrd>::lt>
  12:     0x7fffb4f02e2e - std::panicking::rust_panic_with_hook
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\panicking.rs:841
  13:     0x7fffb4f02b89 - std::panicking::begin_panic_handler::closure$0
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\panicking.rs:706
  14:     0x7fffb4efd4bf - std::sys::backtrace::__rust_end_short_backtrace<std::panicking::begin_panic_handler::closure_env$0,never$>
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\sys\backtrace.rs:168
  15:     0x7fffb4f0278e - std::panicking::begin_panic_handler
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\panicking.rs:697
  16:     0x7fffb808dd61 - core::panicking::panic_fmt
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\core\src\panicking.rs:75
  17:     0x7fffb808e294 - core::panicking::assert_failed_inner
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\core\src\panicking.rs:428
  18:     0x7fffb780fe55 - core[12cfcfafe2bb19e]::panicking::assert_failed::<core[12cfcfafe2bb19e]::option::Option<rustc_middle[e0862b95ef2ad2fa]::ty::Ty>, core[12cfcfafe2bb19e]::option::Option<rustc_middle[e0862b95ef2ad2fa]::ty::Ty>>
  19:     0x7fffb510e2c9 - <rustc_hir_typeck[ef0cb4f4b335c91c]::gather_locals::GatherLocalsVisitor as rustc_hir[8ce3318ddae2e78f]::intravisit::Visitor>::visit_pat
  20:     0x7fffb510de24 - <rustc_hir_typeck[ef0cb4f4b335c91c]::gather_locals::GatherLocalsVisitor as rustc_hir[8ce3318ddae2e78f]::intravisit::Visitor>::visit_pat
  21:     0x7fffb50a355e - <<rustc_hir_typeck[ef0cb4f4b335c91c]::fn_ctxt::FnCtxt>::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir[77ae8ddb4311a279]::visit::TypeVisitor<rustc_middle[e0862b95ef2ad2fa]::ty::context::TyCtxt>>::visit_ty
  22:     0x7fffb5133959 - rustc_hir_typeck[ef0cb4f4b335c91c]::method::probe::method_autoderef_steps
  23:     0x7fffb50a6f3c - <<rustc_hir_typeck[ef0cb4f4b335c91c]::fn_ctxt::FnCtxt>::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir[77ae8ddb4311a279]::visit::TypeVisitor<rustc_middle[e0862b95ef2ad2fa]::ty::context::TyCtxt>>::visit_ty
  24:     0x7fffb5106d22 - <<rustc_hir_typeck[ef0cb4f4b335c91c]::fn_ctxt::FnCtxt>::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir[77ae8ddb4311a279]::visit::TypeVisitor<rustc_middle[e0862b95ef2ad2fa]::ty::context::TyCtxt>>::visit_ty
  25:     0x7fffb50a218e - <<rustc_hir_typeck[ef0cb4f4b335c91c]::fn_ctxt::FnCtxt>::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir[77ae8ddb4311a279]::visit::TypeVisitor<rustc_middle[e0862b95ef2ad2fa]::ty::context::TyCtxt>>::visit_ty
  26:     0x7fffb516aa75 - rustc_hir_typeck[ef0cb4f4b335c91c]::typeck
  27:     0x7fffb51b6160 - <rustc_hir_typeck[ef0cb4f4b335c91c]::upvar::InferBorrowKind as rustc_hir_typeck[ef0cb4f4b335c91c]::expr_use_visitor::Delegate>::borrow
  28:     0x7fffb516a11f - rustc_hir_typeck[ef0cb4f4b335c91c]::typeck
  29:     0x7fffb5e4d7bb - rustc_query_impl[b1e9fe2ed6241a4e]::plumbing::query_key_hash_verify_all
  30:     0x7fffb5d854f4 - RINvNtNtCsjWn63FlaSeo_18rustc_query_system5query8plumbing17try_execute_queryINtCsfh1ZTS0Cz1O_16rustc_query_impl13DynamicConfigINtNtCs1jU3cWLZBn1_21rustc_data_structures9vec_cache8VecCacheNtNtCs7bhVXFTTBeg_10rustc_span6def_id10LocalDefIdINtNtNtCsjh8sONEosqs
  31:     0x7fffb5e55ce2 - rustc_query_impl[b1e9fe2ed6241a4e]::plumbing::query_key_hash_verify_all
  32:     0x7fffb51f06da - RINvMs6_NtCs3jUekHcl3qQ_9hashbrown3rawINtB6_8RawTablejE14reserve_rehashNCINvNtNtCse1pCQVjQKP6_8indexmap3map4core8get_hashTNtNtNtCsjh8sONEosqs_12rustc_middle2ty9predicate6ClauseNtNtCs7bhVXFTTBeg_10rustc_span13span_encoding4SpanEuE0ECs3Zy3ugrYhTr_18rustc_hir
  33:     0x7fffb528d7a3 - rustc_hir_analysis[2e817c42e1dbd083]::check_crate
  34:     0x7fffb4f66553 - <rustc_interface[ce4bd24abdc0293]::passes::LintStoreExpandImpl as rustc_expand[63f6de8acd528e14]::base::LintStoreExpand>::pre_expansion_lint
  35:     0x7fffb186daa7 - rustc_interface[ce4bd24abdc0293]::passes::analysis
  36:     0x7fffb4a7e91a - <alloc[719322561de28682]::sync::Arc<rustc_session[11d32fa8aeb226a]::config::OutputFilenames>>::drop_slow
  37:     0x7fffb498747a - RINvNtNtCsjWn63FlaSeo_18rustc_query_system5query8plumbing17try_execute_queryINtCsfh1ZTS0Cz1O_16rustc_query_impl13DynamicConfigINtNtB4_6caches11SingleCacheINtNtNtCsjh8sONEosqs_12rustc_middle5query5erase6ErasedAhj0_EEKb0_KB3s_KB3s_ENtNtB1f_8plumbing9QueryCtx
  38:     0x7fffb4a84f43 - rustc_query_impl[b1e9fe2ed6241a4e]::query_system
  39:     0x7fffb182ecb5 - std[fc4f8a3a2a49de45]::sys::backtrace::__rust_begin_short_backtrace::<<std[fc4f8a3a2a49de45]::thread::Builder>::spawn_unchecked_<ctrlc[7a845440e34341ae]::set_handler_inner<rustc_driver_impl[33f0ba469f0779bf]::install_ctrlc_handler::{closure#0}>::{closure#0}, ()>::{closure#1}::{closure#0}::{closure#0}, ()>
  40:     0x7fffb1828f13 - std[fc4f8a3a2a49de45]::sys::backtrace::__rust_begin_short_backtrace::<<std[fc4f8a3a2a49de45]::thread::Builder>::spawn_unchecked_<ctrlc[7a845440e34341ae]::set_handler_inner<rustc_driver_impl[33f0ba469f0779bf]::install_ctrlc_handler::{closure#0}>::{closure#0}, ()>::{closure#1}::{closure#0}::{closure#0}, ()>
  41:     0x7fffb182479f - RINvNtNtCslF2IWO2j5Pd_3std3sys9backtrace28___rust_begin_short_backtraceNCNCINvNtCs16DaRdFtSTv_15rustc_interface4util26run_in_thread_with_globalsNCINvB1e_31run_in_thread_pool_with_globalsNCINvNtB1g_9interface12run_compileruNCNvCs4stArJ2l1h3_17rustc_driver_i
  42:     0x7fffb1833010 - std[fc4f8a3a2a49de45]::sys::backtrace::__rust_begin_short_backtrace::<<std[fc4f8a3a2a49de45]::thread::Builder>::spawn_unchecked_<ctrlc[7a845440e34341ae]::set_handler_inner<rustc_driver_impl[33f0ba469f0779bf]::install_ctrlc_handler::{closure#0}>::{closure#0}, ()>::{closure#1}::{closure#0}::{closure#0}, ()>
  43:     0x7fffb4f0719d - alloc::boxed::impl$28::call_once
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\alloc\src\boxed.rs:1966
  44:     0x7fffb4f0719d - alloc::boxed::impl$28::call_once
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\alloc\src\boxed.rs:1966
  45:     0x7fffb4f0719d - std::sys::pal::windows::thread::impl$0::new::thread_start
                               at /rustc/e9f8103f93f8ce2fa2c15c0c6796ec821f8ae15d/library\std\src\sys\pal\windows\thread.rs:56
  46:     0x7ff881247374 - BaseThreadInitThunk
  47:     0x7ff88285cc91 - RtlUserThreadStart

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

query stack during panic:
#0 [typeck] type-checking `main`
#1 [analysis] running analysis passes on this crate
end of query stack

[sososopy]

(It seems that I just saw a question in the comment section?)I just run the rustc command on the latest rustc Nightly version (nightly-2025-05-07-x86_64-pc-windows-msvc)
https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=332b55f3c52ddd31d32fb88f9218f8c6