Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

ICE: E0391 #120241

Closed
matthiaskrgr opened this issue Jan 22, 2024 · 7 comments · Fixed by #120275
Closed

ICE: E0391 #120241

matthiaskrgr opened this issue Jan 22, 2024 · 7 comments · Fixed by #120275
Labels
C-bug Category: This is a bug. F-object_safe_for_dispatch `#![feature(object_safe_for_dispatch)]` I-cycle Issue: A query cycle occurred while none was expected I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

Comments

@matthiaskrgr
Copy link
Member

¯\ (ツ)/¯

auto-reduced (treereduce-rust):

#![feature(object_safe_for_dispatch)]

trait B {
    fn f(a: A) -> A;
}

trait A {
    fn g(b: B) -> B;
}

fn main() {}

original:

#![feature(object_safe_for_dispatch)]

trait B { fn f(a: A) -> A; }
//~^ ERROR associated item referring to unboxed trait object for its own trait
//~| WARN trait objects without an explicit `dyn` are deprecated
//~| WARN trait objects without an explicit `dyn` are deprecated
//~| WARN this is accepted in the current edition
//~| WARN this is accepted in the current edition
//~| WARN this is accepted in the current edition
//~| ERROR the trait `A` cannot be made into an object
trait A { fn g(b: B) -> B; }
//~^ WARN trait objects without an explicit `dyn` are deprecated
//~| WARN trait objects without an explicit `dyn` are deprecated
//~| WARN trait objects without an explicit `dyn` are deprecated
// can't actually invoke it from an object (yet...?).
//~| WARN this is accepted in the current edition
//~| WARN this is accepted in the current edition
//~| ERROR the trait `B` cannot be made into an object
fn main() {}

Version information

rustc 1.77.0-nightly (a58ec8ff0 2024-01-22)
binary: rustc
commit-hash: a58ec8ff03b3269b20104eb7eae407be48ab95a7
commit-date: 2024-01-22
host: x86_64-unknown-linux-gnu
release: 1.77.0-nightly
LLVM version: 17.0.6

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

Program output 

warning: trait objects without an explicit `dyn` are deprecated
 --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:8:13
  |
8 |     fn g(b: B) -> B;
  |             ^
  |
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
  = note: `B` it is not object safe, so it can't be `dyn`
  = note: `#[warn(bare_trait_objects)]` on by default
help: use a new generic type parameter, constrained by `B`
  |
8 |     fn g<T: B>(b: T) -> B;
  |         ++++++    ~
help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
  |
8 |     fn g(b: impl B) -> B;
  |             ++++

warning: trait objects without an explicit `dyn` are deprecated
 --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:8:19
  |
8 |     fn g(b: B) -> B;
  |                   ^
  |
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
help: `B` is not object safe, use `impl B` to return an opaque type, as long as you return a single underlying type
  |
8 |     fn g(b: B) -> impl B;
  |                   ++++

warning: trait objects without an explicit `dyn` are deprecated
 --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:4:13
  |
4 |     fn f(a: A) -> A;
  |             ^
  |
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
  = note: `A` it is not object safe, so it can't be `dyn`
help: use a new generic type parameter, constrained by `A`
  |
4 |     fn f<T: A>(a: T) -> A;
  |         ++++++    ~
help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
  |
4 |     fn f(a: impl A) -> A;
  |             ++++

warning: trait objects without an explicit `dyn` are deprecated
 --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:4:19
  |
4 |     fn f(a: A) -> A;
  |                   ^
  |
  = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
help: `A` is not object safe, use `impl A` to return an opaque type, as long as you return a single underlying type
  |
4 |     fn f(a: A) -> impl A;
  |                   ++++

note: no errors encountered even though `span_delayed_bug` issued

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error[E0391]: cycle detected when computing function signature of `B::f`
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:4:5
   |
4  |     fn f(a: A) -> A;
   |     ^^^^^^^^^^^^^^^^
   |
note: ...which requires checking if trait `A` is object safe...
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:7:1
   |
7  | trait A {
   | ^^^^^^^
note: ...which requires determining object safety of trait `A`...
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:7:1
   |
7  | trait A {
   | ^^^^^^^
note: ...which requires computing function signature of `A::g`...
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:8:5
   |
8  |     fn g(b: B) -> B;
   |     ^^^^^^^^^^^^^^^^
note: ...which requires checking if trait `B` is object safe...
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:3:1
   |
3  | trait B {
   | ^^^^^^^
note: ...which requires determining object safety of trait `B`...
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:3:1
   |
3  | trait B {
   | ^^^^^^^
   = note: ...which again requires computing function signature of `B::f`, completing the cycle
note: cycle used when collecting item types in top-level module
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:1:1
   |
1  | / #![feature(object_safe_for_dispatch)]
2  | |
3  | | trait B {
4  | |     fn f(a: A) -> A;
...  |
10 | |
11 | | fn main() {}
   | |____________^
   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
note: delayed at compiler/rustc_query_system/src/query/job.rs:605:16
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxt>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic_builder::EmissionGuarantee>::emit_producing_guarantee
         3: rustc_query_system::query::plumbing::mk_cycle::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt>
         4: rustc_query_system::query::plumbing::cycle_error::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt>
         5: rustc_query_impl::query_impl::fn_sig::get_query_non_incr::__rust_end_short_backtrace
         6: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>>
         7: rustc_trait_selection::traits::object_safety::virtual_call_violations_for_method
         8: rustc_trait_selection::traits::object_safety::object_safety_violations_for_assoc_item
         9: <core::iter::adapters::flatten::FlatMap<core::iter::adapters::map::Map<core::iter::adapters::map::Map<core::slice::iter::Iter<(rustc_span::symbol::Symbol, rustc_middle::ty::assoc::AssocItem)>, <rustc_data_structures::sorted_map::index_map::SortedIndexMultiMap<u32, rustc_span::symbol::Symbol, rustc_middle::ty::assoc::AssocItem>>::iter::{closure#0}>, <rustc_middle::ty::assoc::AssocItems>::in_definition_order::{closure#0}>, alloc::vec::Vec<rustc_middle::traits::ObjectSafetyViolation>, rustc_trait_selection::traits::object_safety::object_safety_violations_for_trait::{closure#0}> as core::iter::traits::iterator::Iterator>::next
        10: <core::iter::adapters::flatten::FlatMap<rustc_trait_selection::traits::util::SupertraitDefIds, alloc::vec::Vec<rustc_middle::traits::ObjectSafetyViolation>, rustc_trait_selection::traits::object_safety::object_safety_violations::{closure#0}> as core::iter::traits::iterator::Iterator>::next
        11: rustc_trait_selection::traits::object_safety::object_safety_violations
        12: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::object_safety_violations::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 16]>>
        13: <rustc_query_impl::query_impl::object_safety_violations::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_span::def_id::DefId)>>::call_once
        14: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 16]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        15: rustc_query_impl::query_impl::object_safety_violations::get_query_non_incr::__rust_end_short_backtrace
        16: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 16]>>>
        17: rustc_trait_selection::traits::object_safety::check_is_object_safe
        18: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_is_object_safe::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        19: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 1]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        20: rustc_query_impl::query_impl::check_is_object_safe::get_query_non_incr::__rust_end_short_backtrace
        21: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 1]>>>
        22: <dyn rustc_hir_analysis::astconv::AstConv>::maybe_lint_impl_trait
        23: <<dyn rustc_hir_analysis::astconv::AstConv>::maybe_lint_bare_trait::{closure#1} as core::ops::function::FnOnce<(&mut rustc_errors::diagnostic_builder::DiagnosticBuilder<()>,)>>::call_once::{shim:vtable#0}
        24: <alloc::boxed::Box<dyn for<'a, 'b> core::ops::function::FnOnce<(&'a mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'b, ()>,), Output = ()>> as core::ops::function::FnOnce<(&mut rustc_errors::diagnostic_builder::DiagnosticBuilder<()>,)>>::call_once
        25: rustc_middle::lint::struct_lint_level::struct_lint_level_impl::<&str>
        26: <dyn rustc_hir_analysis::astconv::AstConv>::maybe_lint_bare_trait
        27: <dyn rustc_hir_analysis::astconv::AstConv>::ast_ty_to_ty_inner
        28: <dyn rustc_hir_analysis::astconv::AstConv>::ty_of_fn
        29: rustc_hir_analysis::collect::fn_sig
        30: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::fn_sig::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>>
        31: <rustc_query_impl::query_impl::fn_sig::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_span::def_id::DefId)>>::call_once
        32: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        33: rustc_query_impl::query_impl::fn_sig::get_query_non_incr::__rust_end_short_backtrace
        34: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>>
        35: rustc_trait_selection::traits::object_safety::virtual_call_violations_for_method
        36: rustc_trait_selection::traits::object_safety::object_safety_violations_for_assoc_item
        37: <core::iter::adapters::flatten::FlatMap<core::iter::adapters::map::Map<core::iter::adapters::map::Map<core::slice::iter::Iter<(rustc_span::symbol::Symbol, rustc_middle::ty::assoc::AssocItem)>, <rustc_data_structures::sorted_map::index_map::SortedIndexMultiMap<u32, rustc_span::symbol::Symbol, rustc_middle::ty::assoc::AssocItem>>::iter::{closure#0}>, <rustc_middle::ty::assoc::AssocItems>::in_definition_order::{closure#0}>, alloc::vec::Vec<rustc_middle::traits::ObjectSafetyViolation>, rustc_trait_selection::traits::object_safety::object_safety_violations_for_trait::{closure#0}> as core::iter::traits::iterator::Iterator>::next
        38: <core::iter::adapters::flatten::FlatMap<rustc_trait_selection::traits::util::SupertraitDefIds, alloc::vec::Vec<rustc_middle::traits::ObjectSafetyViolation>, rustc_trait_selection::traits::object_safety::object_safety_violations::{closure#0}> as core::iter::traits::iterator::Iterator>::next
        39: rustc_trait_selection::traits::object_safety::object_safety_violations
        40: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::object_safety_violations::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 16]>>
        41: <rustc_query_impl::query_impl::object_safety_violations::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_span::def_id::DefId)>>::call_once
        42: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 16]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        43: rustc_query_impl::query_impl::object_safety_violations::get_query_non_incr::__rust_end_short_backtrace
        44: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 16]>>>
        45: rustc_trait_selection::traits::object_safety::check_is_object_safe
        46: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_is_object_safe::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        47: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 1]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        48: rustc_query_impl::query_impl::check_is_object_safe::get_query_non_incr::__rust_end_short_backtrace
        49: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 1]>>>
        50: <dyn rustc_hir_analysis::astconv::AstConv>::maybe_lint_impl_trait
        51: <<dyn rustc_hir_analysis::astconv::AstConv>::maybe_lint_bare_trait::{closure#1} as core::ops::function::FnOnce<(&mut rustc_errors::diagnostic_builder::DiagnosticBuilder<()>,)>>::call_once::{shim:vtable#0}
        52: <alloc::boxed::Box<dyn for<'a, 'b> core::ops::function::FnOnce<(&'a mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'b, ()>,), Output = ()>> as core::ops::function::FnOnce<(&mut rustc_errors::diagnostic_builder::DiagnosticBuilder<()>,)>>::call_once
        53: rustc_middle::lint::struct_lint_level::struct_lint_level_impl::<&str>
        54: <dyn rustc_hir_analysis::astconv::AstConv>::maybe_lint_bare_trait
        55: <dyn rustc_hir_analysis::astconv::AstConv>::ast_ty_to_ty_inner
        56: <dyn rustc_hir_analysis::astconv::AstConv>::ty_of_fn
        57: rustc_hir_analysis::collect::fn_sig
        58: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::fn_sig::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>>
        59: <rustc_query_impl::query_impl::fn_sig::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_span::def_id::DefId)>>::call_once
        60: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        61: rustc_query_impl::query_impl::fn_sig::get_query_non_incr::__rust_end_short_backtrace
        62: <rustc_hir_analysis::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_trait_item
        63: rustc_hir_analysis::collect::collect_mod_item_types
        64: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::collect_mod_item_types::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
        65: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalModDefId, rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        66: rustc_query_impl::query_impl::collect_mod_item_types::get_query_non_incr::__rust_end_short_backtrace
        67: rustc_hir_analysis::check_crate
        68: rustc_interface::passes::analysis
        69: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        70: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 1]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        71: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        72: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}
        73: std::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>
        74: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
        75: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                   at /rustc/a58ec8ff03b3269b20104eb7eae407be48ab95a7/library/alloc/src/boxed.rs:2016:9
        76: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                   at /rustc/a58ec8ff03b3269b20104eb7eae407be48ab95a7/library/alloc/src/boxed.rs:2016:9
        77: std::sys::pal::unix::thread::Thread::new::thread_start
                   at /rustc/a58ec8ff03b3269b20104eb7eae407be48ab95a7/library/std/src/sys/pal/unix/thread.rs:108:17
        78: <unknown>
        79: <unknown>
  --> /tmp/icemaker_global_tempdir.yPYGjh9iJjgj/rustc_testrunner_tmpdir_reporting.YjRXwTSsOKW4/mvce.rs:4:5
   |
4  |     fn f(a: A) -> A;
   |     ^^^^^^^^^^^^^^^^

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 1.77.0-nightly (a58ec8ff0 2024-01-22) running on x86_64-unknown-linux-gnu

query stack during panic:
end of query stack
error: aborting due to 1 previous error; 4 warnings emitted

For more information about this error, try `rustc --explain E0391`.

@matthiaskrgr matthiaskrgr added I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. C-bug Category: This is a bug. labels Jan 22, 2024
@rustbot rustbot added the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label Jan 22, 2024
@matthiaskrgr
Copy link
Member Author

probably the same problem:

#![feature(object_safe_for_dispatch)]
#![feature(unsized_fn_params)]

fn guard(_s: Copy) -> bool {
    panic!()
}

fn main() {}

@matthiaskrgr
Copy link
Member Author

Seems to be another regression of #119148 cc @estebank

@fmease fmease added F-object_safe_for_dispatch `#![feature(object_safe_for_dispatch)]` and removed needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. labels Jan 22, 2024
@fmease
Copy link
Member

fmease commented Jan 22, 2024

Found another one that has the same backtrace as #120241 (comment):

#![feature(object_safe_for_dispatch)]

trait B {
    fn f(a: A);
}

trait A {
    fn g(b: ());
}

fn main() {}
stderr w/ backtrace 
note: no errors encountered even though `span_delayed_bug` issued

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error[E0782]: trait objects must include the `dyn` keyword
 --> src/main.rs:4:13
  |
4 |     fn f(a: A);
  |             ^
  |
  = note: `A` it is not object safe, so it can't be `dyn`
note: delayed at compiler/rustc_hir_analysis/src/astconv/lint.rs:226:21
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxtInner>::emit_stashed_diagnostics
         2: <rustc_errors::DiagCtxt>::print_error_count
         3: <rustc_session::session::Session>::finish_diagnostics
         4: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}
         5: std::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>
         6: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
         7: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                   at /rustc/ef71f1047e04438181d7cb925a833e2ada6ab390/library/alloc/src/boxed.rs:2016:9
         8: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                   at /rustc/ef71f1047e04438181d7cb925a833e2ada6ab390/library/alloc/src/boxed.rs:2016:9
         9: std::sys::pal::unix::thread::Thread::new::thread_start
                   at /rustc/ef71f1047e04438181d7cb925a833e2ada6ab390/library/std/src/sys/pal/unix/thread.rs:108:17
        10: start_thread
        11: clone
 --> src/main.rs:4:13
  |
4 |     fn f(a: A);
  |             ^
help: use a new generic type parameter, constrained by `A`
  |
4 |     fn f<T: A>(a: T);
  |         ++++++    ~
help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
  |
4 |     fn f(a: impl A);
  |             ++++

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 attach the file at `/playground/rustc-ice-2024-01-22T16_11_23-69.txt` to your bug report

note: compiler flags: --crate-type bin -C embed-bitcode=no -C codegen-units=1 -C debuginfo=2

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

query stack during panic:
end of query stack

@fmease
Copy link
Member

fmease commented Jan 22, 2024

Hmm, I was worried about mutual recursion but I didn't know that it needed object_safe_for_dispatch to trigger.

@compiler-errors
Copy link
Member

I believe this is fixed by #120164

@fmease
Copy link
Member

fmease commented Jan 23, 2024

I believe this is fixed by [the now merged] #120164

Still crashes on the latest master (e35a56d).

@estebank
Copy link
Contributor

estebank commented Jan 23, 2024 •
edited

Ok. I have the smallest possible patch that keeps the nice suggestions in edition >2018 while avoiding most of the problems we are seeing:

https://github.com/rust-lang/rust/pull/119148/files#diff-6811606406d5d02f325d966b59934814111edf12cb48ddd5564448074533c76aR238

Removing that line and unconditionally suggest using dyn in 2015/2018 in the lint (as we did before this change, which is incorrect in some cases) will avoid most of the problems we were seeing because we are assured that an error will emit. Even the delayed recursive query error will not be a problem in that case either.

Edit: #120275

estebank added a commit to estebank/rust that referenced this issue Jan 23, 2024
@estebank
Avoid ICE in trait without dyn lint
c6db42f 
Do not attempt to provide an accurate suggestion for `impl Trait`
in bare trait types when linting. Instead, only do the object
safety check when an E0782 is already going to be emitted in the
2021 edition.

Fix rust-lang#120241.
@estebank estebank mentioned this issue Jan 23, 2024
Merged
estebank added a commit to estebank/rust that referenced this issue Jan 23, 2024
@estebank
Avoid ICE in trait without dyn lint
f562032 
Do not attempt to provide an accurate suggestion for `impl Trait`
in bare trait types when linting. Instead, only do the object
safety check when an E0782 is already going to be emitted in the
2021 edition.

Fix rust-lang#120241.
estebank added a commit to estebank/rust that referenced this issue Jan 23, 2024
@estebank
Avoid ICE in trait without dyn lint
3d9cb5e 
Do not attempt to provide an accurate suggestion for `impl Trait`
in bare trait types when linting. Instead, only do the object
safety check when an E0782 is already going to be emitted in the
2021 edition.

Fix rust-lang#120241.
@fmease fmease added the I-cycle Issue: A query cycle occurred while none was expected label Jan 25, 2024
estebank added a commit to estebank/rust that referenced this issue Jan 27, 2024
@estebank
Avoid ICE in trait without dyn lint
3022c76 
Do not attempt to provide an accurate suggestion for `impl Trait`
in bare trait types when linting. Instead, only do the object
safety check when an E0782 is already going to be emitted in the
2021 edition.

Fix rust-lang#120241.
Nadrieril added a commit to Nadrieril/rust that referenced this issue Jan 27, 2024
@Nadrieril
Rollup merge of rust-lang#120275 - estebank:issue-120241, r=fmease
a58ce1e 
Avoid ICE in trait without `dyn` lint

Do not attempt to provide an accurate suggestion for `impl Trait` in bare trait types when linting. Instead, only do the object safety check when an E0782 is already going to be emitted in the 2021 edition.

Fix rust-lang#120241.
Nadrieril added a commit to Nadrieril/rust that referenced this issue Jan 27, 2024
@Nadrieril
Rollup merge of rust-lang#120275 - estebank:issue-120241, r=fmease
4ada5ef 
Avoid ICE in trait without `dyn` lint

Do not attempt to provide an accurate suggestion for `impl Trait` in bare trait types when linting. Instead, only do the object safety check when an E0782 is already going to be emitted in the 2021 edition.

Fix rust-lang#120241.
Nadrieril added a commit to Nadrieril/rust that referenced this issue Jan 27, 2024
@Nadrieril
Rollup merge of rust-lang#120275 - estebank:issue-120241, r=fmease
60a72b6 
Avoid ICE in trait without `dyn` lint

Do not attempt to provide an accurate suggestion for `impl Trait` in bare trait types when linting. Instead, only do the object safety check when an E0782 is already going to be emitted in the 2021 edition.

Fix rust-lang#120241.
bors added a commit to rust-lang-ci/rust that referenced this issue Jan 29, 2024
@bors
Auto merge of rust-lang#120275 - estebank:issue-120241, r=fmease
af08c64 
Avoid ICE in trait without `dyn` lint

Do not attempt to provide an accurate suggestion for `impl Trait` in bare trait types when linting. Instead, only do the object safety check when an E0782 is already going to be emitted in the 2021 edition.

Fix rust-lang#120241.
@bors bors closed this as completed in 09f16b5 Jan 29, 2024
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
C-bug Category: This is a bug. F-object_safe_for_dispatch `#![feature(object_safe_for_dispatch)]` I-cycle Issue: A query cycle occurred while none was expected I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
Projects
None yet
Milestone
No milestone
Development

Successfully merging a pull request may close this issue.

Avoid ICE in trait without dyn lint estebank/rust
5 participants
@matthiaskrgr @estebank @compiler-errors @fmease @rustbot