ICE during validation of ill-typed static: assertion `left == right` failed at `rustc_const_eval/src/interpret/validity.rs`

[cushionbadak]

Code

(minimized)

static S_COUNT: = std::sync::atomic::AtomicUsize::new(0);

fn main() {}

EDIT: static S_COUNT = std::sync::atomic::AtomicUsize::new(0); also causes ICE.

Original Code

// Reject mixing cyclic structure and Drop when using trait
// objects to hide the cross-references.
//
// (Compare against ui/span/dropck_vec_cycle_checked.rs)

use std::cell::Cell;
use id::Id;

mod s {
    use std::sync::atomic::{AtomicUsize, Ordering};

    static S_COUNT:  = AtomicUsize::new(0);

    pub fn next_count() -> usize {
        S_COUNT.fetch_add(1, Ordering::SeqCst) + 1
    }
}

mod id {
    use s;
    #[derive(Debug)]
    pub struct Id {
        orig_count: usize,
        count: usize,
    }

    impl Id {
        pub fn new() -> Id {
            let c = s::next_count();
            println!("building Id {}", c);
            Id { orig_count: c, count: c }
        }
        pub fn count(&self) -> usize {
            println!("Id::count on {} returns {}", self.orig_count, self.count);
            self.count
        }
    }

    impl Drop for Id {
        fn drop(&mut self) {
            println!("dropping Id {}", self.count);
            self.count = 0;
        }
    }
}

trait HasId {
    fn count(&self) -> usize;
}

#[derive(Debug)]
struct CheckId<T:HasId> {
    v: T
}

#[allow(non_snake_case)]
fn CheckId<T:HasId>(t: T) -> CheckId<T> { CheckId{ v: t } }

impl<T:HasId> Drop for CheckId<T> {
    fn drop(&mut self) {
        assert!(self.v.count() > 0);
    }
}

trait Obj<'a> : HasId {
    fn set0(&self, b: &'a Box<dyn Obj<'a>>);
    fn set1(&self, b: &'a Box<dyn Obj<'a>>);
}

struct O<'a> {
    id: Id,
    obj0: CheckId<Cell<Option<&'a Box<dyn Obj<'a>>>>>,
    obj1: CheckId<Cell<Option<&'a Box<dyn Obj<'a>>>>>,
}

impl<'a> HasId for O<'a> {
    fn count(&self) -> usize { self.id.count() }
}

impl<'a> O<'a> {
    fn new() -> Box<O<'a>> {
        Box::new(O {
            id: Id::new(),
            obj0: CheckId(Cell::new(None)),
            obj1: CheckId(Cell::new(None)),
        })
    }
}

impl<'a> HasId for Cell<Option<&'a Box<dyn Obj<'a>>>> {
    fn count(&self) -> usize {
        match self.get() {
            None => 1,
            Some(c) => c.count(),
        }
    }
}

impl<'a> Obj<'a> for O<'a> {
    fn set0(&self, b: &'a Box<dyn Obj<'a>>) {
        self.obj0.v.set(Some(b))
    }
    fn set1(&self, b: &'a Box<dyn Obj<'a>>) {
        self.obj1.v.set(Some(b))
    }
}


fn f() {
    let (o1, o2, o3): (Box<dyn Obj>, Box<dyn Obj>, Box<dyn Obj>) = (O::new(), O::new(), O::new());
    o1.set0(&o2); //~ ERROR `o2` does not live long enough
    o1.set1(&o3); //~ ERROR `o3` does not live long enough
    o2.set0(&o2); //~ ERROR `o2` does not live long enough
    o2.set1(&o3); //~ ERROR `o3` does not live long enough
    o3.set0(&o1); //~ ERROR `o1` does not live long enough
    o3.set1(&o2); //~ ERROR `o2` does not live long enough
}

fn main() {
    f();
}

Meta

rustc --version --verbose:

rustc 1.79.0-nightly (e3181b091 2024-04-18)
binary: rustc
commit-hash: e3181b091e88321f5ea149afed6db0edf0a4f37b
commit-date: 2024-04-18
host: aarch64-apple-darwin
release: 1.79.0-nightly
LLVM version: 18.1.4

Command

rustc

Error output

error: missing type for `static` item
 --> m_crushed_713540.rs:1:16
  |
1 | static S_COUNT: = std::sync::atomic::AtomicUsize::new(0);
  |                ^ help: provide a type for the static variable: `AtomicUsize`

Backtrace

thread 'rustc' panicked at compiler/rustc_const_eval/src/interpret/validity.rs:727:21:
assertion `left == right` failed
  left: Mut
 right: Not
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed::<rustc_ast_ir::Mutability, rustc_ast_ir::Mutability>
   4: rustc_const_eval::interpret::validity::mutability::<rustc_const_eval::const_eval::machine::CompileTimeInterpreter>
   5: <rustc_const_eval::interpret::validity::ValidityVisitor<rustc_const_eval::const_eval::machine::CompileTimeInterpreter> as rustc_const_eval::interpret::visitor::ValueVisitor<rustc_const_eval::const_eval::machine::CompileTimeInterpreter>>::visit_value
   6: <rustc_const_eval::interpret::validity::ValidityVisitor<rustc_const_eval::const_eval::machine::CompileTimeInterpreter> as rustc_const_eval::interpret::visitor::ValueVisitor<rustc_const_eval::const_eval::machine::CompileTimeInterpreter>>::walk_value
   7: <rustc_const_eval::interpret::eval_context::InterpCx<rustc_const_eval::const_eval::machine::CompileTimeInterpreter>>::validate_operand_internal
   8: rustc_const_eval::const_eval::eval_queries::eval_static_initializer_provider
      [... omitted 2 frames ...]
   9: <rustc_middle::hir::map::Map>::par_body_owners::<rustc_hir_analysis::check_crate::{closure#3}>::{closure#0}
  10: <rustc_data_structures::sync::parallel::ParallelGuard>::run::<(), rustc_data_structures::sync::parallel::enabled::par_for_each_in<&rustc_span::def_id::LocalDefId, &[rustc_span::def_id::LocalDefId], <rustc_middle::hir::map::Map>::par_body_owners<rustc_hir_analysis::check_crate::{closure#3}>::{closure#0}>::{closure#0}::{closure#0}::{closure#0}>
  11: rustc_hir_analysis::check_crate
  12: rustc_interface::passes::analysis
      [... omitted 2 frames ...]
  13: <rustc_middle::ty::context::GlobalCtxt>::enter::<rustc_driver_impl::run_compiler::{closure#0}::{closure#1}::{closure#3}, core::result::Result<(), rustc_span::ErrorGuaranteed>>
  14: <rustc_interface::interface::Compiler>::enter::<rustc_driver_impl::run_compiler::{closure#0}::{closure#1}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_span::ErrorGuaranteed>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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: please attach the file at `/Users/jisukbyun/workspace/placeholder/240420_rustexec/rustc-ice-2024-04-19T15_57_00-86400.txt` to your bug report

query stack during panic:
#0 [eval_static_initializer] evaluating initializer of static `S_COUNT`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 1 previous error

Note

• ICE-loc: compiler/rustc_const_eval/src/interpret/validity.rs:727:21
  

  rust/compiler/rustc_const_eval/src/interpret/validity.rs

  Lines 726 to 728 in e3181b0

  	if let Some((_, alloc)) = ecx.memory.alloc_map.get(alloc_id) {
  	assert_eq!(alloc.mutability, mutability);
  	}

• Original ICE-triggering code is mutated from test-file dropck_trait_cycle_checked.rs
  

  rust/tests/ui/dropck/dropck_trait_cycle_checked.rs

  Line 12 in 07d0d7c

  static S_COUNT: AtomicUsize = AtomicUsize::new(0);

[cushionbadak]

searched nightlies: from nightly-2024-04-01 to nightly-2024-04-19
regressed nightly: nightly-2024-04-19
searched commit range: becebb3...e3181b0
regressed commit: 5260893

bisected with cargo-bisect-rustc v0.6.8

Host triple: aarch64-apple-darwin
Reproduce with:

cargo bisect-rustc --start=2024-04-01 --end=2024-04-19 --preserve --regress=ice -vv

It points to #122684

[RalfJung]

It points to #122684

Cc @oli-obk

[RalfJung]

Oh, this is the usual -- there's an error that should make us not evaluate the static. It doesn't even have a type, how on earth are we trying to evaluate that?!?

[oli-obk]

Probably because of fallback typeck figuring out that the static's type is AtomicUsize and providing that from then on (through HIR and MIR for the body), but failing to account for it from the static's type via type_of.