ICE `adjust mode unimplemented for ConstBlock`

[matthiaskrgr]

auto-reduced (treereduce-rust):

#![feature(deref_patterns)]
fn main() {
    let vec![const { vec![] }]: Vec<usize> = vec![];
}

original:

#![feature(deref_patterns)]
fn main() {
    let vec![const { vec![] }]: Vec<usize> = vec![];

    {
        vec![]
    }
}

Version information

rustc 1.93.0-nightly (a8664a153 2025-10-26)
binary: rustc
commit-hash: a8664a1534913ccff491937ec2dc7ec5d973c2bd
commit-date: 2025-10-26
host: x86_64-unknown-linux-gnu
release: 1.93.0-nightly
LLVM version: 21.1.3

Possibly related line of code:

rust/compiler/rustc_hir_typeck/src/pat.rs

Lines 683 to 695 in a8664a1

	// Path patterns have already been handled, and inline const blocks currently
	// aren't possible to write, so any handling for them would be untested.
	if cfg!(debug_assertions)
	&& self.tcx.features().deref_patterns()
	&& !matches!(lt.kind, PatExprKind::Lit { .. })
	{
	span_bug!(
	lt.span,
	"FIXME(deref_patterns): adjust mode unimplemented for {:?}",
	lt.kind
	);
	}
	// Call `resolve_vars_if_possible` here for inline const blocks.

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

Program output

error[E0532]: expected a pattern, found a function call
 --> /tmp/icemaker_global_tempdir.mXNDgDYHM4YL/rustc_testrunner_tmpdir_reporting.6gH2c4TMrPNV/mvce.rs:3:9
  |
3 |     let vec![const { vec![] }]: Vec<usize> = vec![];
  |         ^^^^^^^^^^^^^^^^^^^^^^ not a tuple struct or tuple variant
  |
  = note: function calls are not allowed in patterns: <https://doc.rust-lang.org/book/ch19-00-patterns.html>
  = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0658]: usage of qualified paths in this context is experimental
 --> /tmp/icemaker_global_tempdir.mXNDgDYHM4YL/rustc_testrunner_tmpdir_reporting.6gH2c4TMrPNV/mvce.rs:3:9
  |
3 |     let vec![const { vec![] }]: Vec<usize> = vec![];
  |         ^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #86935 <https://github.com/rust-lang/rust/issues/86935> for more information
  = help: add `#![feature(more_qualified_paths)]` to the crate attributes to enable
  = note: this compiler was built on 2025-10-26; consider upgrading it if it is out of date
  = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)

warning: the feature `deref_patterns` is incomplete and may not be safe to use and/or cause compiler crashes
 --> /tmp/icemaker_global_tempdir.mXNDgDYHM4YL/rustc_testrunner_tmpdir_reporting.6gH2c4TMrPNV/mvce.rs:1:12
  |
1 | #![feature(deref_patterns)]
  |            ^^^^^^^^^^^^^^
  |
  = note: see issue #87121 <https://github.com/rust-lang/rust/issues/87121> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0164]: expected tuple struct or tuple variant, found associated function `<[_]>::into_vec`
 --> /tmp/icemaker_global_tempdir.mXNDgDYHM4YL/rustc_testrunner_tmpdir_reporting.6gH2c4TMrPNV/mvce.rs:3:9
  |
3 |     let vec![const { vec![] }]: Vec<usize> = vec![];
  |         ^^^^^^^^^^^^^^^^^^^^^^ `fn` calls are not allowed in patterns
  |
  = help: for more information, visit https://doc.rust-lang.org/book/ch19-00-patterns.html
  = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)

error: internal compiler error: compiler/rustc_hir_typeck/src/pat.rs:689:21: FIXME(deref_patterns): adjust mode unimplemented for ConstBlock(ConstBlock { hir_id: HirId(DefId(0:3 ~ mvce[706e]::main).25), def_id: DefId(0:4 ~ mvce[706e]::main::{constant#0}), body: BodyId { hir_id: HirId(DefId(0:3 ~ mvce[706e]::main).26) } })
 --> /tmp/icemaker_global_tempdir.mXNDgDYHM4YL/rustc_testrunner_tmpdir_reporting.6gH2c4TMrPNV/mvce.rs:3:14
  |
3 |     let vec![const { vec![] }]: Vec<usize> = vec![];
  |              ^^^^^^^^^^^^^^^^


thread 'rustc' (2804419) panicked at compiler/rustc_hir_typeck/src/pat.rs:689:21:
Box<dyn Any>
stack backtrace:
   0:     0x7f1cc72b0973 - std::backtrace_rs::backtrace::libunwind::trace::heae8212c72c002b5
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/../../backtrace/src/backtrace/libunwind.rs:117:9
   1:     0x7f1cc72b0973 - std::backtrace_rs::backtrace::trace_unsynchronized::h476583f2b33a8ed0
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/../../backtrace/src/backtrace/mod.rs:66:14
   2:     0x7f1cc72b0973 - std::sys::backtrace::_print_fmt::hc836bf0fe40bb1db
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/sys/backtrace.rs:66:9
   3:     0x7f1cc72b0973 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hf84e64cdd27a2a23
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/sys/backtrace.rs:39:26
   4:     0x7f1cc2635702 - core::fmt::rt::Argument::fmt::h8860ce552ce5bc30
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/core/src/fmt/rt.rs:173:76
   5:     0x7f1cc2635702 - core::fmt::write::h11a59be2c6656721
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/core/src/fmt/mod.rs:1469:25
   6:     0x7f1cc723c609 - std::io::default_write_fmt::hada6ba6c4ae80335
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/io/mod.rs:639:11
   7:     0x7f1cc723c609 - std::io::Write::write_fmt::h63b115eaf01ccee3
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/io/mod.rs:1954:13
   8:     0x7f1cc726189b - std::sys::backtrace::BacktraceLock::print::h4436f6d63c04792d
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/sys/backtrace.rs:42:9
   9:     0x7f1cc726189b - std::panicking::default_hook::{{closure}}::hf85fe377ebbce52f
  10:     0x7f1cc7261435 - std::panicking::default_hook::h341448ad7b6c7250
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panicking.rs:328:9
  11:     0x7f1cc3a48f12 - <alloc[51e647838ce4ca05]::boxed::Box<dyn for<'a, 'b> core[2c4661bac6f6ac6]::ops::function::Fn<(&'a std[64cbbcbf1b940fdd]::panic::PanicHookInfo<'b>,), Output = ()> + core[2c4661bac6f6ac6]::marker::Sync + core[2c4661bac6f6ac6]::marker::Send> as core[2c4661bac6f6ac6]::ops::function::Fn<(&std[64cbbcbf1b940fdd]::panic::PanicHookInfo,)>>::call
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/alloc/src/boxed.rs:2019:9
  12:     0x7f1cc3a48f12 - rustc_driver_impl[c073ed665df9c1b8]::install_ice_hook::{closure#1}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_driver_impl/src/lib.rs:1430:17
  13:     0x7f1cc3a48f12 - <alloc[51e647838ce4ca05]::boxed::Box<rustc_driver_impl[c073ed665df9c1b8]::install_ice_hook::{closure#1}> as core[2c4661bac6f6ac6]::ops::function::Fn<(&dyn for<'a, 'b> core[2c4661bac6f6ac6]::ops::function::Fn<(&'a std[64cbbcbf1b940fdd]::panic::PanicHookInfo<'b>,), Output = ()> + core[2c4661bac6f6ac6]::marker::Sync + core[2c4661bac6f6ac6]::marker::Send, &std[64cbbcbf1b940fdd]::panic::PanicHookInfo)>>::call
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/alloc/src/boxed.rs:2019:9
  14:     0x7f1cc3a48f12 - std[64cbbcbf1b940fdd]::panicking::update_hook::<alloc[51e647838ce4ca05]::boxed::Box<rustc_driver_impl[c073ed665df9c1b8]::install_ice_hook::{closure#1}>>::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panicking.rs:243:47
  15:     0x7f1cc7261eb4 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h656d4e94e6d8d203
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/alloc/src/boxed.rs:2019:9
  16:     0x7f1cc7261eb4 - std::panicking::panic_with_hook::h9a8f9bc8d4484163
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panicking.rs:842:13
  17:     0x7f1cc3b18c93 - std[64cbbcbf1b940fdd]::panicking::begin_panic::<rustc_errors[6510cf1d96c99ae7]::ExplicitBug>::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panicking.rs:771:9
  18:     0x7f1cc3af4886 - std[64cbbcbf1b940fdd]::sys::backtrace::__rust_end_short_backtrace::<std[64cbbcbf1b940fdd]::panicking::begin_panic<rustc_errors[6510cf1d96c99ae7]::ExplicitBug>::{closure#0}, !>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/sys/backtrace.rs:174:18
  19:     0x7f1cc3ae7089 - std[64cbbcbf1b940fdd]::panicking::begin_panic::<rustc_errors[6510cf1d96c99ae7]::ExplicitBug>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panicking.rs:770:5
  20:     0x7f1cc3b68e11 - std[64cbbcbf1b940fdd]::panic::panic_any::<rustc_errors[6510cf1d96c99ae7]::ExplicitBug>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panic.rs:260:5
  21:     0x7f1cc3b68e11 - <rustc_errors[6510cf1d96c99ae7]::diagnostic::BugAbort as rustc_errors[6510cf1d96c99ae7]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_errors/src/diagnostic.rs:63:9
  22:     0x7f1cc4feb4bc - <rustc_errors[6510cf1d96c99ae7]::diagnostic::Diag<rustc_errors[6510cf1d96c99ae7]::diagnostic::BugAbort>>::emit
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_errors/src/diagnostic.rs:1405:9
  23:     0x7f1cc4feb4bc - <rustc_errors[6510cf1d96c99ae7]::DiagCtxtHandle>::span_bug::<rustc_span[2c1246c92d8898ab]::span_encoding::Span, alloc[51e647838ce4ca05]::string::String>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_errors/src/lib.rs:1261:48
  24:     0x7f1cc50876c5 - rustc_middle[3b90aebf889658c7]::util::bug::opt_span_bug_fmt::<rustc_span[2c1246c92d8898ab]::span_encoding::Span>::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_middle/src/util/bug.rs:38:54
  25:     0x7f1cc508799a - rustc_middle[3b90aebf889658c7]::ty::context::tls::with_opt::<rustc_middle[3b90aebf889658c7]::util::bug::opt_span_bug_fmt<rustc_span[2c1246c92d8898ab]::span_encoding::Span>::{closure#0}, !>::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_middle/src/ty/context/tls.rs:136:23
  26:     0x7f1cc5028c16 - rustc_middle[3b90aebf889658c7]::ty::context::tls::with_context_opt::<rustc_middle[3b90aebf889658c7]::ty::context::tls::with_opt<rustc_middle[3b90aebf889658c7]::util::bug::opt_span_bug_fmt<rustc_span[2c1246c92d8898ab]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_middle/src/ty/context/tls.rs:79:18
  27:     0x7f1cc5025eea - rustc_middle[3b90aebf889658c7]::ty::context::tls::with_opt::<rustc_middle[3b90aebf889658c7]::util::bug::opt_span_bug_fmt<rustc_span[2c1246c92d8898ab]::span_encoding::Span>::{closure#0}, !>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_middle/src/ty/context/tls.rs:134:5
  28:     0x7f1cc5025eea - rustc_middle[3b90aebf889658c7]::util::bug::opt_span_bug_fmt::<rustc_span[2c1246c92d8898ab]::span_encoding::Span>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_middle/src/util/bug.rs:33:5
  29:     0x7f1cc5025eea - rustc_middle[3b90aebf889658c7]::util::bug::span_bug_fmt::<rustc_span[2c1246c92d8898ab]::span_encoding::Span>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_middle/src/util/bug.rs:24:5
  30:     0x7f1cc45f2fa7 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::calc_adjust_mode
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:689:21
  31:     0x7f1cc45f2fa7 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:402:32
  32:     0x7f1cc45e0e94 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat_slice
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:2912:18
  33:     0x7f1cc45e0e94 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat_inner
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:645:22
  34:     0x7f1cc45f293b - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:403:23
  35:     0x7f1cc45dde92 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat_inner
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:601:30
  36:     0x7f1cc45f293b - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:403:23
  37:     0x7f1cc45dde92 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat_inner
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:601:30
  38:     0x7f1cc45de5d0 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat_inner
  39:     0x7f1cc45f293b - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:403:23
  40:     0x7f1cc454f223 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_pat_top
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/pat.rs:382:14
  41:     0x7f1cc454f223 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_decl
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs:889:14
  42:     0x7f1cc4554d40 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_decl_local
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs:910:23
  43:     0x7f1cc4554d40 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_stmt
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs:934:22
  44:     0x7f1cc4554d40 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_block::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs:1015:22
  45:     0x7f1cc4554d40 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::with_breakable_ctxt::<<rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_block::{closure#0}, ()>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs:1527:22
  46:     0x7f1cc4554d40 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_block
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs:1013:31
  47:     0x7f1cc446e927 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_kind
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/expr.rs:574:46
  48:     0x7f1cc44a8bc8 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/expr.rs:282:23
  49:     0x7f1cc44a8bc8 - stacker[c1c5f7b2586f5440]::maybe_grow::<rustc_middle[3b90aebf889658c7]::ty::Ty, <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args::{closure#0}>
                               at /rust/deps/stacker-0.1.21/src/lib.rs:57:9
  50:     0x7f1cc44a8bc8 - rustc_data_structures[623314d6c4688740]::stack::ensure_sufficient_stack::<rustc_middle[3b90aebf889658c7]::ty::Ty, <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args::{closure#0}>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_data_structures/src/stack.rs:21:5
  51:     0x7f1cc44a8bc8 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/expr.rs:277:18
  52:     0x7f1cc44a6333 - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_with_expectation
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/expr.rs:222:14
  53:     0x7f1cc44a5b3a - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_expr_with_hint
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/expr.rs:177:14
  54:     0x7f1cc44a5b3a - <rustc_hir_typeck[1949be542646bfbe]::fn_ctxt::FnCtxt>::check_return_or_body_tail
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/expr.rs:1133:35
  55:     0x7f1cc4641aae - rustc_hir_typeck[1949be542646bfbe]::check::check_fn
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/check.rs:130:9
  56:     0x7f1cc4437ec5 - rustc_hir_typeck[1949be542646bfbe]::typeck_with_inspect::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/lib.rs:182:9
  57:     0x7f1cc4459ba6 - rustc_hir_typeck[1949be542646bfbe]::typeck_with_inspect
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_hir_typeck/src/lib.rs:107:1
  58:     0x7f1cc5f08ebe - rustc_query_impl[629cfdbba787a83d]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_query_impl/src/plumbing.rs:294:9
  59:     0x7f1cc5f08ebe - rustc_query_impl[629cfdbba787a83d]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[629cfdbba787a83d]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_query_impl/src/plumbing.rs:578:18
  60:     0x7f1cc63b692f - rustc_query_impl[629cfdbba787a83d]::query_impl::typeck::dynamic_query::{closure#2}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_query_impl/src/plumbing.rs:655:25
  61:     0x7f1cc63b692f - <rustc_query_impl[629cfdbba787a83d]::query_impl::typeck::dynamic_query::{closure#2} as core[2c4661bac6f6ac6]::ops::function::FnOnce<(rustc_middle[3b90aebf889658c7]::ty::context::TyCtxt, rustc_span[2c1246c92d8898ab]::def_id::LocalDefId)>>::call_once
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/core/src/ops/function.rs:250:5
  62:     0x7f1cc60296e6 - <rustc_query_impl[629cfdbba787a83d]::DynamicConfig<rustc_data_structures[623314d6c4688740]::vec_cache::VecCache<rustc_hir_id[9d51473d61962b3]::OwnerId, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[585d893f3b83678a]::dep_graph::graph::DepNodeIndex>, false, false, false> as rustc_query_system[585d893f3b83678a]::query::config::QueryConfig<rustc_query_impl[629cfdbba787a83d]::plumbing::QueryCtxt>>::compute
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_query_impl/src/lib.rs:122:9
  63:     0x7f1cc60296e6 - rustc_query_system[585d893f3b83678a]::query::plumbing::execute_job_non_incr::<rustc_query_impl[629cfdbba787a83d]::DynamicConfig<rustc_data_structures[623314d6c4688740]::vec_cache::VecCache<rustc_hir_id[9d51473d61962b3]::OwnerId, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[585d893f3b83678a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[629cfdbba787a83d]::plumbing::QueryCtxt>::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_query_system/src/query/plumbing.rs:493:72
  64:     0x7f1cc60296e6 - rustc_middle[3b90aebf889658c7]::ty::context::tls::enter_context::<rustc_query_system[585d893f3b83678a]::query::plumbing::execute_job_non_incr<rustc_query_impl[629cfdbba787a83d]::DynamicConfig<rustc_data_structures[623314d6c4688740]::vec_cache::VecCache<rustc_hir_id[9d51473d61962b3]::OwnerId, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[585d893f3b83678a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[629cfdbba787a83d]::plumbing::QueryCtxt>::{closure#0}, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>>::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/compiler/rustc_middle/src/ty/context/tls.rs:60:9
  65:     0x7f1cc60296e6 - <std[64cbbcbf1b940fdd]::thread::local::LocalKey<core[2c4661bac6f6ac6]::cell::Cell<*const ()>>>::try_with::<rustc_middle[3b90aebf889658c7]::ty::context::tls::enter_context<rustc_query_system[585d893f3b83678a]::query::plumbing::execute_job_non_incr<rustc_query_impl[629cfdbba787a83d]::DynamicConfig<rustc_data_structures[623314d6c4688740]::vec_cache::VecCache<rustc_hir_id[9d51473d61962b3]::OwnerId, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[585d893f3b83678a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[629cfdbba787a83d]::plumbing::QueryCtxt>::{closure#0}, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>>::{closure#0}, rustc_middle[3b90aebf889658c7]::query::erase::Erased<[u8; 8usize]>>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/thread/local.rs:508:12
  
< snip > 

 154:     0x7f1cc3a33263 - std[64cbbcbf1b940fdd]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/sys/backtrace.rs:158:18
 155:     0x7f1cc3a50f64 - <std[64cbbcbf1b940fdd]::thread::Builder>::spawn_unchecked_::<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/thread/mod.rs:562:17
 156:     0x7f1cc3a50f64 - <core[2c4661bac6f6ac6]::panic::unwind_safe::AssertUnwindSafe<<std[64cbbcbf1b940fdd]::thread::Builder>::spawn_unchecked_<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}> as core[2c4661bac6f6ac6]::ops::function::FnOnce<()>>::call_once
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/core/src/panic/unwind_safe.rs:274:9
 157:     0x7f1cc3a50f64 - std[64cbbcbf1b940fdd]::panicking::catch_unwind::do_call::<core[2c4661bac6f6ac6]::panic::unwind_safe::AssertUnwindSafe<<std[64cbbcbf1b940fdd]::thread::Builder>::spawn_unchecked_<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}>, ()>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panicking.rs:590:40
 158:     0x7f1cc3a50f64 - std[64cbbcbf1b940fdd]::panicking::catch_unwind::<(), core[2c4661bac6f6ac6]::panic::unwind_safe::AssertUnwindSafe<<std[64cbbcbf1b940fdd]::thread::Builder>::spawn_unchecked_<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}>>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panicking.rs:553:19
 159:     0x7f1cc3a50f64 - std[64cbbcbf1b940fdd]::panic::catch_unwind::<core[2c4661bac6f6ac6]::panic::unwind_safe::AssertUnwindSafe<<std[64cbbcbf1b940fdd]::thread::Builder>::spawn_unchecked_<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}>, ()>
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/panic.rs:359:14
 160:     0x7f1cc3a50f64 - <std[64cbbcbf1b940fdd]::thread::Builder>::spawn_unchecked_::<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/thread/mod.rs:560:30
 161:     0x7f1cc3a50f64 - <<std[64cbbcbf1b940fdd]::thread::Builder>::spawn_unchecked_<rustc_interface[35bb7f6c97091001]::util::run_in_thread_with_globals<rustc_interface[35bb7f6c97091001]::util::run_in_thread_pool_with_globals<rustc_interface[35bb7f6c97091001]::interface::run_compiler<(), rustc_driver_impl[c073ed665df9c1b8]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[2c4661bac6f6ac6]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
                               at /rustc-dev/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/core/src/ops/function.rs:250:5
 162:     0x7f1cc7251b85 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb679a76bc5040637
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/alloc/src/boxed.rs:2005:9
 163:     0x7f1cc7251b85 - std::sys::thread::unix::Thread::new::thread_start::h84b2d2778567a179
                               at /rustc/a8664a1534913ccff491937ec2dc7ec5d973c2bd/library/std/src/sys/thread/unix.rs:126:17
 164:     0x7f1cc0a969cb - <unknown>
 165:     0x7f1cc0b1aa0c - <unknown>
 166:                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 1.93.0-nightly (a8664a153 2025-10-26) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `main`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 4 previous errors; 1 warning emitted

Some errors have detailed explanations: E0164, E0532, E0658.
For more information about an error, try `rustc --explain E0164`.

@rustbot label +F-deref_patterns

[Nadrieril]

I cannot begin to understand the level of cursed that makes the expansion of vec![] somehow end up as a PatKind::Expr x) This should just be a delayed bug instead of instant bug. I don't care enough to fix it.

[Rohithkumar2030]

Hello @matthiaskrgr , I’m new to this project (and open source as a whole) and would love to work on this issue as a first contribution. I’m still getting familiar with the codebase.i would really appreciate you suggestions on getting started
If the issue is still open, I’d be happy to take it up.

[karolzwolak]

Welcome to the project @Rohithkumar2030!

Yes. the issue should be still open — no one is assigned to it.
If you're starting to work on it — mark it so by using @rustbot claim.
There's gonna be a lot of useful information and tips on rustc dev guide.

As for how to get started I'd do:

• pull the latest version of rustc & build it
• reproduce this issue using your compiled version of rustc

To run the repro using your local version of rustc you can:

• add this as a test to rust/tests/ui/pattern/deref-patterns/ dir
• compile it directly using something like rustc +stage1 bug.rs (for +stage1 you need to create rustup toolchain)

Adding a test will require slightly more work than compiling with rustc directly — you don't have to do this yet.
I like to do that though — because it gives you highly reproducible environment.
To run your just test: ./x test tests/ui/pattern/deref-patterns/<test-name>.rs .

---

As for how to actually debug this and what to change:

I'm not familiar with this code — but we have a backtrace here — we can trace the execution path.
I'd look though the functions in the backtrace and try to understand roughly what's happening here.

useful links on how to debug rustc:
https://rustc-dev-guide.rust-lang.org/compiler-debugging.html
https://rustc-dev-guide.rust-lang.org/compiler-debugging.html#getting-a-backtrace-for-errors
https://rustc-dev-guide.rust-lang.org/compiler-debugging.html#debugging-delayed-bugs

[Nadrieril]

The example code is already emitting errors, the only problem is that we crash instead of just reporting them. The fix for that is to replace the span_bug mentioned in the description with span_delayed_bug. Feel free to assign me to the PR when you make it.