ICE: typeck: no index for a field

snippet:

struct TestStruct {,}

fn edge_case_if() {
    let ts = TestStruct {};
    let _b = || { match ts {
        TestStruct{ x: 1, .. } | _ => (),
    }};
}

Version information

rustc 1.81.0-nightly (1ca578e68 2024-06-20)
binary: rustc
commit-hash: 1ca578e68eb715e772fc0c1b9e6ca7c5b122765a
commit-date: 2024-06-20
host: x86_64-unknown-linux-gnu
release: 1.81.0-nightly
LLVM version: 18.1.7

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

Program output

error: expected identifier, found `,`
 --> /tmp/icemaker_global_tempdir.hJLG4Uu9QCDq/rustc_testrunner_tmpdir_reporting.cVa4rm3LGIDH/mvce.rs:1:20
  |
1 | struct TestStruct {,}
  |        ----------  ^ expected identifier
  |        |
  |        while parsing this struct

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.hJLG4Uu9QCDq/rustc_testrunner_tmpdir_reporting.cVa4rm3LGIDH/mvce.rs:8:2
  |
8 | }
  |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.hJLG4Uu9QCDq/rustc_testrunner_tmpdir_reporting.cVa4rm3LGIDH/mvce.rs`

thread 'rustc' panicked at compiler/rustc_hir_typeck/src/expr_use_visitor.rs:1697:26:
no index for a field
stack backtrace:
   0:     0x71e31da31915 - std::backtrace_rs::backtrace::libunwind::trace::h796e75e96c439f3e
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1:     0x71e31da31915 - std::backtrace_rs::backtrace::trace_unsynchronized::h57b5b13bb46e11ba
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x71e31da31915 - std::sys::backtrace::_print_fmt::h11ce45f986076e87
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/sys/backtrace.rs:68:5
   3:     0x71e31da31915 - <std::sys::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hcd09ba6a4fc236f1
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/sys/backtrace.rs:44:22
   4:     0x71e31da824bb - core::fmt::rt::Argument::fmt::h914f09f4a1c58d59
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/core/src/fmt/rt.rs:165:63
   5:     0x71e31da824bb - core::fmt::write::hc590b91d463e6a2c
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/core/src/fmt/mod.rs:1168:21
   6:     0x71e31da265af - std::io::Write::write_fmt::hc69b1d0ded026622
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/io/mod.rs:1835:15
   7:     0x71e31da316ee - std::sys::backtrace::_print::hc852e4497da27a95
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/sys/backtrace.rs:47:5
   8:     0x71e31da316ee - std::sys::backtrace::print::hc624de700d5fe576
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/sys/backtrace.rs:34:9
   9:     0x71e31da34129 - std::panicking::default_hook::{{closure}}::hf8d8481f1d9702fb
  10:     0x71e31da33ecc - std::panicking::default_hook::he469b58de751f8ee
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/panicking.rs:292:9
  11:     0x71e31a147870 - std[eca1b30e63fdea7a]::panicking::update_hook::<alloc[79c37403ec1ba474]::boxed::Box<rustc_driver_impl[93e75e0175b92285]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x71e31da34a4f - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h7fb9108d23a6d563
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/alloc/src/boxed.rs:2076:9
  13:     0x71e31da34a4f - std::panicking::rust_panic_with_hook::h738066c73a52890f
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/panicking.rs:804:13
  14:     0x71e31da34677 - std::panicking::begin_panic_handler::{{closure}}::h8534a2aac695431b
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/panicking.rs:670:13
  15:     0x71e31da31dd9 - std::sys::backtrace::__rust_end_short_backtrace::h3420ee35d28bf807
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/sys/backtrace.rs:171:18
  16:     0x71e31da34304 - rust_begin_unwind
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/panicking.rs:661:5
  17:     0x71e31da7ea73 - core::panicking::panic_fmt::h51cb44e3a97167f8
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/core/src/panicking.rs:74:14
  18:     0x71e31da7e8cb - core::panicking::panic_display::h01c80b100e2db3b0
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/core/src/panicking.rs:264:5
  19:     0x71e31da7e8cb - core::option::expect_failed::h227980ecada19c49
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/core/src/option.rs:2023:5
  20:     0x71e31c05cd08 - <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::cat_pattern::<<rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::maybe_read_scrutinee<core[daaba097f859fa28]::iter::adapters::map::Map<core[daaba097f859fa28]::slice::iter::Iter<rustc_hir[f2dc79efc6c2027e]::hir::Arm>, <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::walk_expr::{closure#1}>>::{closure#0}>
  21:     0x71e31c05c919 - <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::cat_pattern::<<rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::maybe_read_scrutinee<core[daaba097f859fa28]::iter::adapters::map::Map<core[daaba097f859fa28]::slice::iter::Iter<rustc_hir[f2dc79efc6c2027e]::hir::Arm>, <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::walk_expr::{closure#1}>>::{closure#0}>
  22:     0x71e31c0669c0 - <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::walk_expr
  23:     0x71e31c0656b0 - <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::consume_expr
  24:     0x71e31c06404e - <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::walk_block
  25:     0x71e31c0656b0 - <rustc_hir_typeck[3a3cc19eb2dfac16]::expr_use_visitor::ExprUseVisitor<&rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt, &mut rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKind>>::consume_expr
  26:     0x71e31c05e887 - <rustc_hir_typeck[3a3cc19eb2dfac16]::fn_ctxt::FnCtxt>::analyze_closure
  27:     0x71e31900c688 - <rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKindVisitor as rustc_hir[f2dc79efc6c2027e]::intravisit::Visitor>::visit_expr
  28:     0x71e31b8a58ef - <rustc_hir_typeck[3a3cc19eb2dfac16]::upvar::InferBorrowKindVisitor as rustc_hir[f2dc79efc6c2027e]::intravisit::Visitor>::visit_block
  29:     0x71e31b8a780b - rustc_hir_typeck[3a3cc19eb2dfac16]::typeck
  30:     0x71e31b8a6ffb - rustc_query_impl[da2d3b64247f93f0]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[da2d3b64247f93f0]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a7abdaade2c6424c]::query::erase::Erased<[u8; 8usize]>>
  31:     0x71e31ba031ee - rustc_query_system[5e65d9b3abdd3162]::query::plumbing::try_execute_query::<rustc_query_impl[da2d3b64247f93f0]::DynamicConfig<rustc_query_system[5e65d9b3abdd3162]::query::caches::VecCache<rustc_span[1efc0ab8e6bb0790]::def_id::LocalDefId, rustc_middle[a7abdaade2c6424c]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[da2d3b64247f93f0]::plumbing::QueryCtxt, false>
  32:     0x71e31ba01cdf - rustc_query_impl[da2d3b64247f93f0]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  33:     0x71e31ba01915 - <rustc_middle[a7abdaade2c6424c]::hir::map::Map>::par_body_owners::<rustc_hir_analysis[74e881c9b9f2b37]::check_crate::{closure#4}>::{closure#0}
  34:     0x71e31ba003bc - rustc_hir_analysis[74e881c9b9f2b37]::check_crate
  35:     0x71e31bdf4f87 - rustc_interface[7fb7dc76513cf959]::passes::analysis
  36:     0x71e31bdf4ac7 - rustc_query_impl[da2d3b64247f93f0]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[da2d3b64247f93f0]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a7abdaade2c6424c]::query::erase::Erased<[u8; 1usize]>>
  37:     0x71e31c433ea5 - rustc_query_system[5e65d9b3abdd3162]::query::plumbing::try_execute_query::<rustc_query_impl[da2d3b64247f93f0]::DynamicConfig<rustc_query_system[5e65d9b3abdd3162]::query::caches::SingleCache<rustc_middle[a7abdaade2c6424c]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[da2d3b64247f93f0]::plumbing::QueryCtxt, false>
  38:     0x71e31c433c0f - rustc_query_impl[da2d3b64247f93f0]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  39:     0x71e31c2dd252 - rustc_interface[7fb7dc76513cf959]::interface::run_compiler::<core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>, rustc_driver_impl[93e75e0175b92285]::run_compiler::{closure#0}>::{closure#1}
  40:     0x71e31c29dac9 - std[eca1b30e63fdea7a]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[7fb7dc76513cf959]::util::run_in_thread_with_globals<rustc_interface[7fb7dc76513cf959]::util::run_in_thread_pool_with_globals<rustc_interface[7fb7dc76513cf959]::interface::run_compiler<core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>, rustc_driver_impl[93e75e0175b92285]::run_compiler::{closure#0}>::{closure#1}, core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>>::{closure#0}, core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>>
  41:     0x71e31c29d880 - <<std[eca1b30e63fdea7a]::thread::Builder>::spawn_unchecked_<rustc_interface[7fb7dc76513cf959]::util::run_in_thread_with_globals<rustc_interface[7fb7dc76513cf959]::util::run_in_thread_pool_with_globals<rustc_interface[7fb7dc76513cf959]::interface::run_compiler<core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>, rustc_driver_impl[93e75e0175b92285]::run_compiler::{closure#0}>::{closure#1}, core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>>::{closure#0}, core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[daaba097f859fa28]::result::Result<(), rustc_span[1efc0ab8e6bb0790]::ErrorGuaranteed>>::{closure#2} as core[daaba097f859fa28]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  42:     0x71e31da3e8cb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::ha1ad2417ff4e2c89
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/alloc/src/boxed.rs:2062:9
  43:     0x71e31da3e8cb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::ha5ab2243447620ef
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/alloc/src/boxed.rs:2062:9
  44:     0x71e31da3e8cb - std::sys::pal::unix::thread::Thread::new::thread_start::he00df2d38aeed7a5
                               at /rustc/1ca578e68eb715e772fc0c1b9e6ca7c5b122765a/library/std/src/sys/pal/unix/thread.rs:108:17
  45:     0x71e316ca6ded - <unknown>
  46:     0x71e316d2a0dc - <unknown>
  47:                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 1.81.0-nightly (1ca578e68 2024-06-20) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `edge_case_if`
#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 E0601`.

@oli-obk

#126320 cc @oli-obk :D

wtf. why does that wrong comma cause the struct to be different from a struct with no fields

minimized

struct X {,}

fn main() {
    || {
        if let X { x: 1,} = (X {}) {}
    };
}

wtf. why does that wrong comma cause the struct to be different from a struct with no fields

An extra , is a recovered struct variant, and it is skipped here:

rust/compiler/rustc_hir_typeck/src/pat.rs

Line 1533 in 382148d

    
           let inexistent_fields_err = if !(inexistent_fields.is_empty() || variant.is_recovered())

so we didn't emit the error like an empty struct:

rust/compiler/rustc_hir_typeck/src/pat.rs

Line 1610 in 382148d

(Some(err), None) => Err(err.emit()),

error[E0026]: struct `X` does not have a field named `x`
 --> src/main.rs:5:20
  |
5 |         if let X { x: 1,} = (X {}) {}
  |                    ^ struct `X` does not have this field

So the compiler continues until the ICE point.

I think a trivial fix will be ok here?

Hmm... I'd look into reporting that error even for recovered structs and figuring out how to avoid it just for the cases that this skip was intended to avoid

seems there is nothing else we are trying to avoid:

2ea2bb4

I'd prefer not to report the no-field error, since the first error in parsing will point out the root cause, and there is a case like #126344, which may introduce noise when there are too many type errors, it's also applied to this issue.

Oh... we can probably just replace the is_recovered method with a new tainted_by_errors method and return an Result<(), ErrorGuaranteed>. This way we act as if we reported an error, and thus not continue to the ICE

Since we cannot encode an ErrorGuaranteed in the flags list, either take a TyCtxt argument on the tainted_by_errors method, or check if replacing the field field with Result<IndexVec<FieldIdx, FieldDef>, ErrorGuaranteed> works out nicely

Auto merge of rust-lang#127575 - chenyukang:yukang-fix-struct-fields-…

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ICE: typeck: `no index for a field` #126744

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ICE: typeck: no index for a field #126744

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matthiaskrgr commented on Jun 20, 2024

oli-obk commented on Jun 21, 2024

matthiaskrgr commented on Jun 21, 2024

chenyukang commented on Jul 7, 2024

oli-obk commented on Jul 7, 2024

chenyukang commented on Jul 8, 2024

oli-obk commented on Jul 8, 2024

oli-obk commented on Jul 8, 2024

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ICE: typeck: `no index for a field` #126744