ICE: `unexpected resolution for an identifier in pattern`

[matthiaskrgr]

auto-reduced (treereduce-rust):

use Bar::foo;

trait Bar {
    fn foo(&self) {}
}

fn main() {
    let foo: Arc<dyn Foo> = propagate2(&j);
}

original code

original:

// Check that more complex receivers work:
// terminator of the MIR, which has had the PostAnalysisNormalize pass performed on it.
//@ error-pattern: Uninitialized value was created by an allocation

//@ revisions: cfi kcfi

//@ only-linux
//@ [cfi] needs-sanitizer-cfi
//@ [kcfi] needs-sanitizer-kcfi
//@ compile-flags: -C target-feature=-crt-static
//@ compile-flags: --crate-type=bin -Cprefer-dynamic=off -Clto -Zsanitizer=cfi
//@ [cfi] compile-flags: -Z sanitizer=cfi
//@ [kcfi] compile-flags: -Z sanitizer=kcfi
//@ [kcfi] compile-flags: -C panic=abort -C prefer-dynamic=off
//@ run-pass

use Bar::foo;

trait Foo {
    fn foo(self: Arc<Self>)(&self)
}

struct FooImpl;

impl Foo for C {
    fn rpit_fn(self: Iter<Self>) {}
}

trait Bar {
    fn foo(&self) {}
}

struct BarImpl;

impl Bar for BarImpl {
    type T = i32;
    fn bar(&self) -> Self::T { 7 }
}

fn main() {
    let foo: Arc<dyn Foo> = propagate2(&j);
    foo.as_ptr();

    let bar: &dyn Yprintln!("p1")T=i32> = &BarImpl
    assert_eq!(use_closure_once.bar(), 3);
}

Version information

rustc 1.86.0-nightly (bb3fa4b48 2025-01-17)
binary: rustc
commit-hash: bb3fa4b48eef8dc0815b0464e56f1fb82fe2cdfc
commit-date: 2025-01-17
host: x86_64-unknown-linux-gnu
release: 1.86.0-nightly
LLVM version: 19.1.7

Possibly related line of code:

rust/compiler/rustc_resolve/src/late.rs

Lines 4015 to 4027 in bb3fa4b

	self.r.dcx().span_delayed_bug(
	ident.span,
	"unexpected `SelfCtor` in pattern, expected identifier"
	);
	None
	}
	_ => span_bug!(
	ident.span,
	"unexpected resolution for an identifier in pattern: {:?}",
	res,
	),
	}
	}

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

Program output

error[E0658]: `use` associated items of traits is unstable
 --> /tmp/icemaker_global_tempdir.Z7Hkc1ETV8nn/rustc_testrunner_tmpdir_reporting.2yoSVIHoUPEC/mvce.rs:1:5
  |
1 | use Bar::foo;
  |     ^^^^^^^^
  |
  = note: see issue #134691 <https://github.com/rust-lang/rust/issues/134691> for more information
  = help: add `#![feature(import_trait_associated_functions)]` to the crate attributes to enable
  = note: this compiler was built on 2025-01-17; consider upgrading it if it is out of date

error: internal compiler error: compiler/rustc_resolve/src/late.rs:4021:18: unexpected resolution for an identifier in pattern: Def(AssocFn, DefId(0:5 ~ mvce[144b]::Bar::foo))
 --> /tmp/icemaker_global_tempdir.Z7Hkc1ETV8nn/rustc_testrunner_tmpdir_reporting.2yoSVIHoUPEC/mvce.rs:8:9
  |
8 |     let foo: Arc<dyn Foo> = propagate2(&j);
  |         ^^^


thread 'rustc' panicked at compiler/rustc_resolve/src/late.rs:4021:18:
Box<dyn Any>
stack backtrace:
   0:     0x7edbcc0f683a - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h23c1af5b93b45c4e
   1:     0x7edbcc812d66 - core::fmt::write::he6ce13e554e79ce6
   2:     0x7edbcd795b91 - std::io::Write::write_fmt::hec6f02e202dc5849
   3:     0x7edbcc0f6692 - std::sys::backtrace::BacktraceLock::print::hc275ab55e4e7012b
   4:     0x7edbcc0f8b12 - std::panicking::default_hook::{{closure}}::ha505ca355cb30c7e
   5:     0x7edbcc0f899a - std::panicking::default_hook::h19ac97dfcd221a6d
   6:     0x7edbcb25a9fb - std[31774604a6320310]::panicking::update_hook::<alloc[371b401ffbdd17ea]::boxed::Box<rustc_driver_impl[6ffd8ce43d36b65a]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x7edbcc0f9693 - std::panicking::rust_panic_with_hook::h5c0132368c99678a
   8:     0x7edbcb296341 - std[31774604a6320310]::panicking::begin_panic::<rustc_errors[98a8ad297a61928c]::ExplicitBug>::{closure#0}
   9:     0x7edbcb28b246 - std[31774604a6320310]::sys::backtrace::__rust_end_short_backtrace::<std[31774604a6320310]::panicking::begin_panic<rustc_errors[98a8ad297a61928c]::ExplicitBug>::{closure#0}, !>
  10:     0x7edbcb287f7d - std[31774604a6320310]::panicking::begin_panic::<rustc_errors[98a8ad297a61928c]::ExplicitBug>
  11:     0x7edbcb2a0271 - <rustc_errors[98a8ad297a61928c]::diagnostic::BugAbort as rustc_errors[98a8ad297a61928c]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x7edbcb7f7c9c - <rustc_errors[98a8ad297a61928c]::DiagCtxtHandle>::span_bug::<rustc_span[2051e39db7245042]::span_encoding::Span, alloc[371b401ffbdd17ea]::string::String>
  13:     0x7edbcb87d537 - rustc_middle[d6b3b4678fa8d253]::util::bug::opt_span_bug_fmt::<rustc_span[2051e39db7245042]::span_encoding::Span>::{closure#0}
  14:     0x7edbcb862d5a - rustc_middle[d6b3b4678fa8d253]::ty::context::tls::with_opt::<rustc_middle[d6b3b4678fa8d253]::util::bug::opt_span_bug_fmt<rustc_span[2051e39db7245042]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  15:     0x7edbcb862beb - rustc_middle[d6b3b4678fa8d253]::ty::context::tls::with_context_opt::<rustc_middle[d6b3b4678fa8d253]::ty::context::tls::with_opt<rustc_middle[d6b3b4678fa8d253]::util::bug::opt_span_bug_fmt<rustc_span[2051e39db7245042]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  16:     0x7edbca225da7 - rustc_middle[d6b3b4678fa8d253]::util::bug::span_bug_fmt::<rustc_span[2051e39db7245042]::span_encoding::Span>
  17:     0x7edbcd49a91e - <rustc_ast[a21bb4063d307b10]::ast::Pat>::walk::<<rustc_resolve[ef634132eb20349a]::late::LateResolutionVisitor>::resolve_pattern_inner::{closure#0}>
  18:     0x7edbcd49aceb - <rustc_resolve[ef634132eb20349a]::late::LateResolutionVisitor>::resolve_pattern_top
  19:     0x7edbcd493282 - <rustc_resolve[ef634132eb20349a]::late::LateResolutionVisitor>::resolve_block
  20:     0x7edbcd49c9ea - <rustc_resolve[ef634132eb20349a]::late::LateResolutionVisitor as rustc_ast[a21bb4063d307b10]::visit::Visitor>::visit_fn
  21:     0x7edbcd4b42fd - rustc_ast[a21bb4063d307b10]::visit::walk_item_ctxt::<rustc_resolve[ef634132eb20349a]::late::LateResolutionVisitor, rustc_ast[a21bb4063d307b10]::ast::ItemKind>
  22:     0x7edbcd4bd17b - <rustc_resolve[ef634132eb20349a]::late::LateResolutionVisitor as rustc_ast[a21bb4063d307b10]::visit::Visitor>::visit_item
  23:     0x7edbcda2778a - <rustc_resolve[ef634132eb20349a]::Resolver>::resolve_crate::{closure#0}
  24:     0x7edbcda2377f - <rustc_resolve[ef634132eb20349a]::Resolver>::resolve_crate
  25:     0x7edbccdcd1d7 - rustc_interface[d0fa5b755e7f54c8]::passes::resolver_for_lowering_raw
  26:     0x7edbccdcc227 - rustc_query_impl[61d446cd41769aac]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[61d446cd41769aac]::query_impl::resolver_for_lowering_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[d6b3b4678fa8d253]::query::erase::Erased<[u8; 16usize]>>
  27:     0x7edbccdcc215 - <rustc_query_impl[61d446cd41769aac]::query_impl::resolver_for_lowering_raw::dynamic_query::{closure#2} as core[a9419c698344facd]::ops::function::FnOnce<(rustc_middle[d6b3b4678fa8d253]::ty::context::TyCtxt, ())>>::call_once
  28:     0x7edbcd764cb6 - rustc_query_system[2ef7fec5ec5d5e8e]::query::plumbing::try_execute_query::<rustc_query_impl[61d446cd41769aac]::DynamicConfig<rustc_query_system[2ef7fec5ec5d5e8e]::query::caches::SingleCache<rustc_middle[d6b3b4678fa8d253]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[61d446cd41769aac]::plumbing::QueryCtxt, false>
  29:     0x7edbcd764960 - rustc_query_impl[61d446cd41769aac]::query_impl::resolver_for_lowering_raw::get_query_non_incr::__rust_end_short_backtrace
  30:     0x7edbcd7c03b0 - rustc_interface[d0fa5b755e7f54c8]::passes::create_and_enter_global_ctxt::<core[a9419c698344facd]::option::Option<rustc_interface[d0fa5b755e7f54c8]::queries::Linker>, rustc_driver_impl[6ffd8ce43d36b65a]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  31:     0x7edbcd801456 - rustc_interface[d0fa5b755e7f54c8]::interface::run_compiler::<(), rustc_driver_impl[6ffd8ce43d36b65a]::run_compiler::{closure#0}>::{closure#1}
  32:     0x7edbcd7325c7 - std[31774604a6320310]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[d0fa5b755e7f54c8]::util::run_in_thread_with_globals<rustc_interface[d0fa5b755e7f54c8]::util::run_in_thread_pool_with_globals<rustc_interface[d0fa5b755e7f54c8]::interface::run_compiler<(), rustc_driver_impl[6ffd8ce43d36b65a]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  33:     0x7edbcd732299 - <<std[31774604a6320310]::thread::Builder>::spawn_unchecked_<rustc_interface[d0fa5b755e7f54c8]::util::run_in_thread_with_globals<rustc_interface[d0fa5b755e7f54c8]::util::run_in_thread_pool_with_globals<rustc_interface[d0fa5b755e7f54c8]::interface::run_compiler<(), rustc_driver_impl[6ffd8ce43d36b65a]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[a9419c698344facd]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  34:     0x7edbcd731a2f - std::sys::pal::unix::thread::Thread::new::thread_start::h1ff917b0bfabc673
  35:     0x7edbc7aa339d - <unknown>
  36:     0x7edbc7b2849c - <unknown>
  37:                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 1.86.0-nightly (bb3fa4b48 2025-01-17) 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

For more information about this error, try `rustc --explain E0658`.

[matthiaskrgr]

mvce I think

use A::b;

trait A {
    fn b() {}
}

fn main() {
    let b: ();
}

[matthiaskrgr]

bisects to #134754

@frank-king can you make it so that we don't ICE when the feature is not enabled with a feature gate for now?

[frank-king]

I think we should just let the associated functions be silently shadowed here, just like non-associated functions

rust/compiler/rustc_resolve/src/late.rs

Line 4008 in 6067b36

Res::Def(DefKind::Fn, _) | Res::Local(..) | Res::Err => {

And a similar issue I found is the associated constants:

use Num::{ZERO, one};

trait Num {
    const ZERO: Self;
}

impl Num for u32 {
    const ZERO: u32 = 0;
}

fn foo(x: u32) -> u32 {
    // AssocConst in patterns and expressions
    if let ZERO = x { ZERO } else { 1 }
}

fn main() {}

[frank-king]

@matthiaskrgr The original code example you provided is syntactically incorrect (but no ICE if #135663 is applied), could you please have a check?

Code

// Check that more complex receivers work:
// terminator of the MIR, which has had the PostAnalysisNormalize pass performed on it.
//@ error-pattern: Uninitialized value was created by an allocation

//@ revisions: cfi kcfi

//@ only-linux
//@ [cfi] needs-sanitizer-cfi
//@ [kcfi] needs-sanitizer-kcfi
//@ compile-flags: -C target-feature=-crt-static
//@ compile-flags: --crate-type=bin -Cprefer-dynamic=off -Clto -Zsanitizer=cfi
//@ [cfi] compile-flags: -Z sanitizer=cfi
//@ [kcfi] compile-flags: -Z sanitizer=kcfi
//@ [kcfi] compile-flags: -C panic=abort -C prefer-dynamic=off
//@ run-pass

use Bar::foo;

trait Foo {
    fn foo(self: Arc<Self>)(&self)
}

struct FooImpl;

impl Foo for C {
    fn rpit_fn(self: Iter<Self>) {}
}

trait Bar {
    fn foo(&self) {}
}

struct BarImpl;

impl Bar for BarImpl {
    type T = i32;
    fn bar(&self) -> Self::T { 7 }
}

fn main() {
    let foo: Arc<dyn Foo> = propagate2(&j);
    foo.as_ptr();

    let bar: &dyn Yprintln!("p1")T=i32> = &BarImpl
    assert_eq!(use_closure_once.bar(), 3);
}

compiler stderr

error: expected one of `->`, `;`, `where`, or `{`, found `(`
  --> $DIR/resolve-issue-135614.rs:20:28
   |
LL | trait Foo {
   |           - while parsing this item list starting here
LL |     fn foo(self: Arc<Self>)(&self)
   |                            ^ expected one of `->`, `;`, `where`, or `{`
LL | }
   | - the item list ends here

error: expected one of `(`, `+`, `::`, `;`, `<`, or `=`, found `!`
  --> $DIR/resolve-issue-135614.rs:44:27
   |
LL |     let bar: &dyn Yprintln!("p1")T=i32> = &BarImpl
   |            -              ^ expected one of `(`, `+`, `::`, `;`, `<`, or `=`
   |            |
   |            while parsing the type for `bar`

error[E0658]: `use` associated items of traits is unstable
  --> $DIR/resolve-issue-135614.rs:17:5
   |
LL | use Bar::foo;
   |     ^^^^^^^^
   |
   = note: see issue #134691 <https://github.com/rust-lang/rust/issues/134691> for more information
   = help: add `#![feature(import_trait_associated_functions)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error[E0407]: method `rpit_fn` is not a member of trait `Foo`
  --> $DIR/resolve-issue-135614.rs:26:5
   |
LL |     fn rpit_fn(self: Iter<Self>) {}
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not a member of trait `Foo`

error[E0437]: type `T` is not a member of trait `Bar`
  --> $DIR/resolve-issue-135614.rs:36:5
   |
LL |     type T = i32;
   |     ^^^^^^^^^^^^^ not a member of trait `Bar`

error[E0407]: method `bar` is not a member of trait `Bar`
  --> $DIR/resolve-issue-135614.rs:37:5
   |
LL |     fn bar(&self) -> Self::T { 7 }
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not a member of trait `Bar`

error[E0412]: cannot find type `C` in this scope
  --> $DIR/resolve-issue-135614.rs:25:14
   |
LL | impl Foo for C {
   |              ^ not found in this scope

error[E0412]: cannot find type `Iter` in this scope
  --> $DIR/resolve-issue-135614.rs:26:22
   |
LL |     fn rpit_fn(self: Iter<Self>) {}
   |                      ^^^^ not found in this scope
   |
help: consider importing one of these structs
   |
LL + use std::collections::binary_heap::Iter;
   |
LL + use std::collections::btree_map::Iter;
   |
LL + use std::collections::btree_set::Iter;
   |
LL + use std::collections::hash_map::Iter;
   |
     and 9 other candidates

error[E0412]: cannot find type `Arc` in this scope
  --> $DIR/resolve-issue-135614.rs:41:14
   |
LL |     let foo: Arc<dyn Foo> = propagate2(&j);
   |              ^^^ not found in this scope
   |
help: consider importing this struct
   |
LL + use std::sync::Arc;
   |

error[E0425]: cannot find value `j` in this scope
  --> $DIR/resolve-issue-135614.rs:41:41
   |
LL |     let foo: Arc<dyn Foo> = propagate2(&j);
   |                                         ^ not found in this scope

warning: unused import: `Bar::foo`
  --> $DIR/resolve-issue-135614.rs:17:5
   |
LL | use Bar::foo;
   |     ^^^^^^^^
   |
   = note: `#[warn(unused_imports)]` on by default

error[E0220]: associated type `T` not found for `Self`
  --> $DIR/resolve-issue-135614.rs:37:28
   |
LL |     fn bar(&self) -> Self::T { 7 }
   |                            ^ associated type `T` not found

error[E0425]: cannot find function `propagate2` in this scope
  --> $DIR/resolve-issue-135614.rs:41:29
   |
LL |     let foo: Arc<dyn Foo> = propagate2(&j);
   |                             ^^^^^^^^^^ not found in this scope

error: aborting due to 12 previous errors; 1 warning emitted

Some errors have detailed explanations: E0220, E0407, E0412, E0425, E0437, E0658.
For more information about an error, try `rustc --explain E0220`.