Internal Compiler Error with RefCell

[DuncanConroy]

I was reading up on the Rust book and basically playing around with RefCell without knowing what I was doing :P

Code

use std::ops::Add;
use std::cell::RefCell;

#[derive(Debug)]
struct Bla{
    hello:String
}
static FOO:RefCell<Option<Bla>> = RefCell::new(None);
fn main() -> String {
    let mut output = String::new();
    output.add(&format!("FOO: {:#?}", FOO.into_inner().unwrap()));

    output
}

Meta

rustc --version --verbose:

rustc 1.53.0-nightly (132b4e5d1 2021-04-13)
binary: rustc
commit-hash: 132b4e5d167b7e622fcc11fa2b67b931105b4de1
commit-date: 2021-04-13
host: x86_64-apple-darwin
release: 1.53.0-nightly
LLVM version: 12.0.0

Error output

thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(4565771098143344972, 7869445775526300234))`,
 right: `Some(Fingerprint(14934403843752251060, 623484215826468126))`: found unstable fingerprints for predicates_of(core[8495]::ops::arith::Add): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Rhs as std::marker::Sized>), []), /Users/daniel.bunte/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/arith.rs:75:15: 75:18 (#0)), (Binder(TraitPredicate(<Self as std::ops::Add<Rhs>>), []), /Users/daniel.bunte/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/arith.rs:75:1: 75:26 (#0))] }', /rustc/132b4e5d167b7e622fcc11fa2b67b931105b4de1/compiler/rustc_query_system/src/query/plumbing.rs:593:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

error: internal compiler error: unexpected panic

note: 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: rustc 1.53.0-nightly (132b4e5d1 2021-04-13) running on x86_64-apple-darwin

note: compiler flags: -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [predicates_of] computing predicates of `std::ops::Add`
#1 [typeck] type-checking `main`
end of query stack
error: could not compile `hellorust`

Backtrace

╭─daniel.bunte in ~/development/hellorust on master using 21-04-19 - 15:29:27
╰─🍓 cargo run
   Compiling hellorust v0.1.0 (/Users/daniel.bunte/development/hellorust)
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Some(Fingerprint(4565771098143344972, 7869445775526300234))`,
 right: `Some(Fingerprint(14934403843752251060, 623484215826468126))`: found unstable fingerprints for predicates_of(core[8495]::ops::arith::Add): GenericPredicates { parent: None, predicates: [(Binder(TraitPredicate(<Rhs as std::marker::Sized>), []), /Users/daniel.bunte/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/arith.rs:75:15: 75:18 (#0)), (Binder(TraitPredicate(<Self as std::ops::Add<Rhs>>), []), /Users/daniel.bunte/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/arith.rs:75:1: 75:26 (#0))] }', /rustc/132b4e5d167b7e622fcc11fa2b67b931105b4de1/compiler/rustc_query_system/src/query/plumbing.rs:593:5
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: rustc_query_system::query::plumbing::incremental_verify_ich
   5: rustc_query_system::query::plumbing::load_from_disk_and_cache_in_memory
   6: rustc_data_structures::stack::ensure_sufficient_stack
   7: rustc_query_system::query::plumbing::get_query_impl
   8: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::predicates_of
   9: rustc_middle::ty::generics::GenericPredicates::instantiate_into
  10: rustc_middle::ty::generics::GenericPredicates::instantiate
  11: rustc_typeck::check::method::confirm::ConfirmContext::confirm
  12: rustc_typeck::check::method::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::lookup_method
  13: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_kind
  14: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  15: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_stmt
  16: rustc_typeck::check::fn_ctxt::checks::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_block_with_expected
  17: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_expr_with_expectation
  18: rustc_typeck::check::expr::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::check_return_expr
  19: rustc_typeck::check::check::check_fn
  20: rustc_infer::infer::InferCtxtBuilder::enter
  21: rustc_typeck::check::typeck
  22: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  23: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  24: rustc_data_structures::stack::ensure_sufficient_stack
  25: rustc_query_system::query::plumbing::force_query_with_job
  26: rustc_query_system::query::plumbing::get_query_impl
  27: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck
  28: rustc_middle::ty::<impl rustc_middle::ty::context::TyCtxt>::par_body_owners
  29: rustc_typeck::check::typeck_item_bodies
  30: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  31: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  32: rustc_data_structures::stack::ensure_sufficient_stack
  33: rustc_query_system::query::plumbing::force_query_with_job
  34: rustc_query_system::query::plumbing::get_query_impl
  35: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::typeck_item_bodies
  36: rustc_session::utils::<impl rustc_session::session::Session>::time
  37: rustc_typeck::check_crate
  38: rustc_interface::passes::analysis
  39: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  40: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  41: rustc_data_structures::stack::ensure_sufficient_stack
  42: rustc_query_system::query::plumbing::force_query_with_job
  43: rustc_query_system::query::plumbing::get_query_impl
  44: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  45: rustc_interface::passes::QueryContext::enter
  46: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  47: rustc_span::with_source_map
  48: rustc_interface::interface::create_compiler_and_run
  49: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

note: 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: rustc 1.53.0-nightly (132b4e5d1 2021-04-13) running on x86_64-apple-darwin

note: compiler flags: -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [predicates_of] computing predicates of `std::ops::Add`
#1 [typeck] type-checking `main`
#2 [typeck_item_bodies] type-checking all item bodies
#3 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `hellorust`

[Aaron1011]

@DuncanConroy: Do you remember what changes you were making before this happened? In particular, did you adjust or update your version of Rust using rustup?

[DuncanConroy]

Unfortunately, I don't remember the last change before I reduced it to this version. I haven't updated via rustup.

…

On Mon, Apr 19, 2021, 21:17 Aaron Hill ***@***.***> wrote: @DuncanConroy <https://github.com/DuncanConroy>: Do you remember what changes you were making before this happened? In particular, did you adjust or update your version of Rust using rustup? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#84336 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAYU7LO2JPLPRIXZN77ZMGDTJR6UFANCNFSM43F4DTNQ> .

[wesleywiser]

Thanks for filing the bug report! We are currently triaging issues related to #84970 to ensure each underlying problem gets resolved. Since this appears to be a duplicate of #83259, I'm going to close in favor of that issue.