ICE: `unexpected 'SelfCtor' in pattern, expected identifier`

[matthiaskrgr]

auto-reduced (treereduce-rust):

impl Foo { fn main() {
    
    let S { ref Self } = RAW_SLICE_TOO_LONG; 

    
     

    ;
} }

original:

struct Baz { q: Option<Foo> }
//~^ ERROR recursive types `Baz` and `Foo` have infinite size

struct Foo { q: Option<Baz> }

impl Foo { fn main() {
    let s = S { f1: 123 };
    let S { ref Self } = RAW_SLICE_TOO_LONG; //~ ERROR unused variable

    let points = vec![Point { x: 1, y: 2 }];
    let _: i32 = points.iter().map(|Point { x, y }| y).sum(); //~ ERROR unused variable

    match (s.0, 0) {
    TEST2 => println!("matched"),
    //~^ ERROR behave unpredictably
    _ => panic!("didn't match")
  };
} }

fn main() {}

Version information

rustc 1.84.0-nightly (3fee0f12e 2024-11-20)
binary: rustc
commit-hash: 3fee0f12e4f595948f8f54f57c8b7a7a58127124
commit-date: 2024-11-20
host: x86_64-unknown-linux-gnu
release: 1.84.0-nightly
LLVM version: 19.1.3

Possibly related line of code:

rust/compiler/rustc_resolve/src/late.rs

Lines 3939 to 3951 in 3fee0f1

	None
	}
	Res::SelfCtor(_) => {
	// We resolve `Self` in pattern position as an ident sometimes during recovery,
	// so delay a bug instead of ICEing. (Note: is this no longer true? We now ICE. If
	// this triggers, please convert to a delayed bug and add a test.)
	self.r.dcx().span_bug(
	ident.span,
	"unexpected `SelfCtor` in pattern, expected identifier"
	);
	}
	_ => span_bug!(
	ident.span,

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc

Program output

error: expected identifier, found keyword `Self`
 --> /tmp/icemaker_global_tempdir.MevH4NlT2UPr/rustc_testrunner_tmpdir_reporting.rUbmgP8E1aau/mvce.rs:8:17
  |
8 |     let S { ref Self } = RAW_SLICE_TOO_LONG; 
  |                 ^^^^ expected identifier, found keyword

error: internal compiler error: unexpected `SelfCtor` in pattern, expected identifier
 --> /tmp/icemaker_global_tempdir.MevH4NlT2UPr/rustc_testrunner_tmpdir_reporting.rUbmgP8E1aau/mvce.rs:8:17
  |
8 |     let S { ref Self } = RAW_SLICE_TOO_LONG; 
  |                 ^^^^

thread 'rustc' panicked at compiler/rustc_resolve/src/late.rs:3945:30:
Box<dyn Any>
stack backtrace:
   0:     0x70dca9e75eca - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h462aecd04ea9579e
   1:     0x70dcaa623362 - core::fmt::write::h90ee43f9ea3cba58
   2:     0x70dcaba7d091 - std::io::Write::write_fmt::hedeb5e5db4a69c5c
   3:     0x70dca9e75d22 - std::sys::backtrace::BacktraceLock::print::h4cd84f50718730a5
   4:     0x70dca9e781fa - std::panicking::default_hook::{{closure}}::hd4c3e895ac68f35a
   5:     0x70dca9e78060 - std::panicking::default_hook::h63638a03e198d592
   6:     0x70dca8efbc25 - std[2244cad2f80807fb]::panicking::update_hook::<alloc[cbefbba4106c24e6]::boxed::Box<rustc_driver_impl[a02cca374e721ba2]::install_ice_hook::{closure#0}>>::{closure#0}
   7:     0x70dca9e788d8 - std::panicking::rust_panic_with_hook::hb612322ec5da5d64
   8:     0x70dca8f362a1 - std[2244cad2f80807fb]::panicking::begin_panic::<rustc_errors[f9771b9e181d5533]::ExplicitBug>::{closure#0}
   9:     0x70dca8f29266 - std[2244cad2f80807fb]::sys::backtrace::__rust_end_short_backtrace::<std[2244cad2f80807fb]::panicking::begin_panic<rustc_errors[f9771b9e181d5533]::ExplicitBug>::{closure#0}, !>
  10:     0x70dca8f24839 - std[2244cad2f80807fb]::panicking::begin_panic::<rustc_errors[f9771b9e181d5533]::ExplicitBug>
  11:     0x70dca8f401d1 - <rustc_errors[f9771b9e181d5533]::diagnostic::BugAbort as rustc_errors[f9771b9e181d5533]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x70dca9a0ebf4 - <rustc_errors[f9771b9e181d5533]::DiagCtxtHandle>::span_bug::<rustc_span[17c8ace98e68264b]::span_encoding::Span, &str>
  13:     0x70dcab3da5cf - <rustc_ast[cb4a9f145e050deb]::ast::Pat>::walk::<<rustc_resolve[da9d6586afcb5ccb]::late::LateResolutionVisitor>::resolve_pattern_inner::{closure#0}>
  14:     0x70dcab3d945a - <rustc_ast[cb4a9f145e050deb]::ast::Pat>::walk::<<rustc_resolve[da9d6586afcb5ccb]::late::LateResolutionVisitor>::resolve_pattern_inner::{closure#0}>
  15:     0x70dcab3e7cf2 - <rustc_resolve[da9d6586afcb5ccb]::late::LateResolutionVisitor>::resolve_block
  16:     0x70dcab3e1be9 - <rustc_resolve[da9d6586afcb5ccb]::late::LateResolutionVisitor as rustc_ast[cb4a9f145e050deb]::visit::Visitor>::visit_fn
  17:     0x70dcab40d3a7 - <rustc_resolve[da9d6586afcb5ccb]::late::LateResolutionVisitor as rustc_ast[cb4a9f145e050deb]::visit::Visitor>::visit_item
  18:     0x70dcab9a3ff8 - <rustc_resolve[da9d6586afcb5ccb]::Resolver>::resolve_crate::{closure#0}
  19:     0x70dcab99e4bf - <rustc_resolve[da9d6586afcb5ccb]::Resolver>::resolve_crate
  20:     0x70dcaaa9f94f - rustc_interface[c2b60ea3c5f8ab84]::passes::resolver_for_lowering_raw
  21:     0x70dcaaa9ea4d - rustc_query_impl[6938d1d3b9759c59]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[6938d1d3b9759c59]::query_impl::resolver_for_lowering_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[65a7c84fae00e80e]::query::erase::Erased<[u8; 16usize]>>
  22:     0x70dcaaa9ea25 - <rustc_query_impl[6938d1d3b9759c59]::query_impl::resolver_for_lowering_raw::dynamic_query::{closure#2} as core[f62530bb87197118]::ops::function::FnOnce<(rustc_middle[65a7c84fae00e80e]::ty::context::TyCtxt, ())>>::call_once
  23:     0x70dcab5e9b24 - rustc_query_system[37669824fe84eed8]::query::plumbing::try_execute_query::<rustc_query_impl[6938d1d3b9759c59]::DynamicConfig<rustc_query_system[37669824fe84eed8]::query::caches::SingleCache<rustc_middle[65a7c84fae00e80e]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[6938d1d3b9759c59]::plumbing::QueryCtxt, false>
  24:     0x70dcab5e97e0 - rustc_query_impl[6938d1d3b9759c59]::query_impl::resolver_for_lowering_raw::get_query_non_incr::__rust_end_short_backtrace
  25:     0x70dcab50ff9e - rustc_interface[c2b60ea3c5f8ab84]::interface::run_compiler::<core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>, rustc_driver_impl[a02cca374e721ba2]::run_compiler::{closure#0}>::{closure#1}
  26:     0x70dcab5401e0 - std[2244cad2f80807fb]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[c2b60ea3c5f8ab84]::util::run_in_thread_with_globals<rustc_interface[c2b60ea3c5f8ab84]::util::run_in_thread_pool_with_globals<rustc_interface[c2b60ea3c5f8ab84]::interface::run_compiler<core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>, rustc_driver_impl[a02cca374e721ba2]::run_compiler::{closure#0}>::{closure#1}, core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>>::{closure#0}, core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>>
  27:     0x70dcab53fefd - <<std[2244cad2f80807fb]::thread::Builder>::spawn_unchecked_<rustc_interface[c2b60ea3c5f8ab84]::util::run_in_thread_with_globals<rustc_interface[c2b60ea3c5f8ab84]::util::run_in_thread_pool_with_globals<rustc_interface[c2b60ea3c5f8ab84]::interface::run_compiler<core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>, rustc_driver_impl[a02cca374e721ba2]::run_compiler::{closure#0}>::{closure#1}, core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>>::{closure#0}, core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[f62530bb87197118]::result::Result<(), rustc_span[17c8ace98e68264b]::ErrorGuaranteed>>::{closure#1} as core[f62530bb87197118]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  28:     0x70dcab53f6b9 - std::sys::pal::unix::thread::Thread::new::thread_start::hbfb59c93227878ea
  29:     0x70dcacd9c39d - <unknown>
  30:     0x70dcace2149c - <unknown>
  31:                0x0 - <unknown>

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 1.84.0-nightly (3fee0f12e 2024-11-20) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [resolver_for_lowering_raw] getting the resolver for lowering
end of query stack
error: aborting due to 2 previous errors

[matthiaskrgr]

impl Foo {
   fn fun() {
        let S { ref Self } = todo!();
   }
}

[matthiaskrgr]

Regression in nightly-2024-02-22

commit[0] 2024-02-20: Auto merge of #121345 - Nilstrieb:rollup-reb0xge, r=Nilstrieb
commit[1] 2024-02-20: Auto merge of #121356 - matthiaskrgr:rollup-d80af2s, r=matthiaskrgr
commit[2] 2024-02-21: Auto merge of #120904 - Nadrieril:match-lowering-intermediate-repr, r=matthewjasper
commit[3] 2024-02-21: Auto merge of #121172 - Nadrieril:simplify-empty-selection, r=matthewjasper
commit[4] 2024-02-21: Auto merge of #121380 - weihanglo:update-cargo, r=weihanglo
commit[5] 2024-02-21: Auto merge of #120588 - alexcrichton:wasm-rmeta-object, r=wesleywiser,bjorn3
commit[6] 2024-02-21: Auto merge of #120718 - saethlin:reasonable-fast-math, r=nnethercote
commit[7] 2024-02-21: Auto merge of #121383 - Dylan-DPC:rollup-735p4u4, r=Dylan-DPC
commit[8] 2024-02-21: Auto merge of #121400 - fmease:rollup-8m29g7a, r=fmease
commit[9] 2024-02-21: Auto merge of #121321 - compiler-errors:yeet-querytyperelating, r=lcnr
commit[10] 2024-02-21: Auto merge of #117658 - RalfJung:ptr-dangling, r=m-ou-se

[jieyouxu]

This is because #121208 changed the delayed_bug to bug, but it just means that we lacked any test coverage that could've hit that.