ICE with Bevy on nightly

[deontologician]

Code

use bevy::{
    ecs::query::{Fetch, FilterFetch, WorldQuery},
    prelude::*,
};

pub(crate) fn get_children_mut<Q, F, C>(children: &Children, q: &mut Query<Q, F>, mut callback: C)
where
    C: FnMut(<<Q as WorldQuery>::Fetch as Fetch>::Item),
    Q: WorldQuery,
    F: WorldQuery,
    F::Fetch: FilterFetch,
{
    children.iter().for_each(move |child_id| {
        if let Ok(result) = q.get_mut(*child_id) {
            callback(result);
        }
    });
}

fn query_children_system(children: Query<&Children>, mut selections: Query<Entity>) {
    for children in children.iter() {
        get_children_mut(children, &mut selections, |_| {})
    }
}

fn main() {
    App::build().add_system(query_children_system.system());
}

Cargo.toml

[package]
name = "ice_repro"
version = "0.1.0"
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
bevy = {version="0.5.0", default-features=false}

Meta

rustc --version --verbose:

rustc 1.56.0-nightly (08095fc1f 2021-07-26)
binary: rustc
commit-hash: 08095fc1f875c89e507f17cf6c6a780c8ffa4c01
commit-date: 2021-07-26
host: x86_64-unknown-linux-gnu
release: 1.56.0-nightly
LLVM version: 12.0.1

Additionally, I have the following .cargo/config.toml

[target.x86_64-unknown-linux-gnu]
linker = "/usr/bin/clang"
rustflags = ["-Clink-arg=-fuse-ld=lld", "-Zshare-generics=y"]

Error output

error: internal compiler error: compiler/rustc_trait_selection/src/traits/codegen.rs:78:17: Encountered error `OutputTypeParameterMismatch(Binder(<[closure@src/main.rs:23:53: 23:59] as std::ops::FnMut<(<bevy::ecs::query::EntityFetch as bevy::ecs::query::Fetch<'_>>::Item,)>>, [Region(BrAnon(0))]), Binder(<[closure@src/main.rs:23:53: 23:59] as std::ops::FnMut<(bevy::prelude::Entity,)>>, []), Sorts(ExpectedFound { expected: bevy::prelude::Entity, found: <bevy::ecs::query::EntityFetch as bevy::ecs::query::Fetch<'_>>::Item }))` selecting `Binder(<[closure@src/main.rs:23:53: 23:59] as std::ops::FnMut<(bevy::prelude::Entity,)>>, [])` during codegen

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1034:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

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 1.56.0-nightly (08095fc1f 2021-07-26) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z share-generics=y -C opt-level=3 -C embed-bitcode=no -C linker=/usr/bin/clang -C link-arg=-fuse-ld=lld --crate-type bin

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

query stack during panic:
#0 [codegen_fulfill_obligation] checking if `std::ops::FnMut` fulfills its obligations
#1 [resolve_instance] resolving instance `<[closure@src/main.rs:23:53: 23:59] as std::ops::FnMut<(bevy::prelude::Entity,)>>::call_mut`
end of query stack
error: could not compile `ice_repro`

Backtrace

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1034:9
stack backtrace:
   0: std::panicking::begin_panic
   1: std::panic::panic_any
   2: rustc_errors::HandlerInner::bug
   3: rustc_errors::Handler::bug
   4: rustc_middle::ty::context::tls::with_opt
   5: rustc_middle::util::bug::opt_span_bug_fmt
   6: rustc_middle::util::bug::bug_fmt
   7: rustc_infer::infer::InferCtxtBuilder::enter
   8: rustc_trait_selection::traits::codegen::codegen_fulfill_obligation
   9: rustc_query_system::query::plumbing::get_query_impl
  10: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::codegen_fulfill_obligation
  11: rustc_ty_utils::instance::inner_resolve_instance
  12: rustc_ty_utils::instance::resolve_instance
  13: rustc_query_system::query::plumbing::get_query_impl
  14: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::resolve_instance
  15: rustc_middle::ty::instance::Instance::resolve_opt_const_arg
  16: rustc_middle::ty::instance::Instance::resolve
  17: <rustc_mir::monomorphize::collector::MirNeighborCollector as rustc_middle::mir::visit::Visitor>::visit_terminator
  18: rustc_mir::monomorphize::collector::collect_neighbours
  19: rustc_mir::monomorphize::collector::collect_items_rec
  20: rustc_mir::monomorphize::collector::collect_items_rec
  21: rustc_mir::monomorphize::collector::collect_items_rec
  22: rustc_mir::monomorphize::collector::collect_items_rec
  23: rustc_mir::monomorphize::collector::collect_items_rec
  24: rustc_mir::monomorphize::collector::collect_items_rec
  25: rustc_mir::monomorphize::collector::collect_items_rec
  26: rustc_mir::monomorphize::collector::collect_items_rec
  27: rustc_mir::monomorphize::collector::collect_items_rec
  28: rustc_mir::monomorphize::collector::collect_items_rec
  29: rustc_mir::monomorphize::collector::collect_items_rec
  30: rustc_mir::monomorphize::collector::collect_items_rec
  31: rustc_mir::monomorphize::collector::collect_items_rec
  32: rustc_mir::monomorphize::collector::collect_items_rec
  33: rustc_mir::monomorphize::collector::collect_items_rec
  34: rustc_mir::monomorphize::collector::collect_items_rec
  35: rustc_mir::monomorphize::collector::collect_crate_mono_items
  36: rustc_mir::monomorphize::partitioning::collect_and_partition_mono_items
  37: rustc_query_system::query::plumbing::get_query_impl
  38: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::collect_and_partition_mono_items
  39: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
  40: rustc_interface::passes::QueryContext::enter
  41: rustc_interface::queries::Queries::ongoing_codegen
  42: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  43: rustc_span::with_source_map
  44: rustc_interface::interface::create_compiler_and_run
  45: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[deontologician]

Apologies for not getting a more minimal example, bevy's ECS has a bunch of stuff going on.

[hellow554]

trait Fetch<'world> {
    type Item;
}

struct Query<Q>(Q);

impl<Q: WorldQuery> Query<Q> {
    fn get_mut(&mut self) -> <Q::Fetch as Fetch>::Item {
        todo!()
    }
}

trait WorldQuery {
    type Fetch: for<'world> Fetch<'world>;
}
impl WorldQuery for () {
    type Fetch = WorldFetch;
}
struct WorldFetch;
impl<'w, 's> Fetch<'w> for WorldFetch {
    type Item = ();
}

fn get_children_mut<Q, C>(q: &mut Query<Q>, callback: C)
where
    Q: WorldQuery,
    C: Fn(<<Q as WorldQuery>::Fetch as Fetch>::Item),
{
    callback(q.get_mut());
}

fn main() {
    get_children_mut(&mut Query(()), |_| {});
}

Backtrace

error: internal compiler error: compiler/rustc_trait_selection/src/traits/codegen.rs:78:17: Encountered error `OutputTypeParameterMismatch(Binder(<[closure@src/main.rs:33:38: 33:44] as std::ops::Fn<(<WorldFetch as Fetch<'_>>::Item,)>>, [Region(BrAnon(0))]), Binder(<[closure@src/main.rs:33:38: 33:44] as std::ops::Fn<((),)>>, []), Sorts(ExpectedFound { expected: (), found: <WorldFetch as Fetch<'_>>::Item }))` selecting `Binder(<[closure@src/main.rs:33:38: 33:44] as std::ops::Fn<((),)>>, [])` during codegen

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1046:9
stack backtrace:
   0:     0x7fc0c52a9d80 - std::backtrace_rs::backtrace::libunwind::trace::h820df6e5a36600f2
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
   1:     0x7fc0c52a9d80 - std::backtrace_rs::backtrace::trace_unsynchronized::h08422e102b839b36
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fc0c52a9d80 - std::sys_common::backtrace::_print_fmt::h57fa141da5c1d78f
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x7fc0c52a9d80 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::he771973a791a4e00
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/sys_common/backtrace.rs:46:22
   4:     0x7fc0c5317f4c - core::fmt::write::h9a6d9c74526a6c1b
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/core/src/fmt/mod.rs:1117:17
   5:     0x7fc0c529b685 - std::io::Write::write_fmt::h9d3df603db3c3ca4
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/io/mod.rs:1667:15
   6:     0x7fc0c52ad33b - std::sys_common::backtrace::_print::ha158db1ea88125c4
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/sys_common/backtrace.rs:49:5
   7:     0x7fc0c52ad33b - std::sys_common::backtrace::print::h342dde07e263fe00
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/sys_common/backtrace.rs:36:9
   8:     0x7fc0c52ad33b - std::panicking::default_hook::{{closure}}::h642e95a669718f6e
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/panicking.rs:210:50
   9:     0x7fc0c52aceb0 - std::panicking::default_hook::hc5055134d92c4284
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/panicking.rs:227:9
  10:     0x7fc0c5a8d731 - rustc_driver::DEFAULT_HOOK::{{closure}}::{{closure}}::h304e91c4dd9ccf1e
  11:     0x7fc0c52adb69 - std::panicking::rust_panic_with_hook::h6f45f3f96085621d
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/panicking.rs:628:17
  12:     0x7fc0c6a4dd5b - std::panicking::begin_panic::{{closure}}::ha486b1482929756f
  13:     0x7fc0c6a4dce6 - std::sys_common::backtrace::__rust_end_short_backtrace::h3f9d04b762f19ede
  14:     0x7fc0c6a4edff - std::panicking::begin_panic::h08c493e41a1b6bd8
  15:     0x7fc0c6a6327d - std::panic::panic_any::hcbbea2fdace6d4dc
  16:     0x7fc0c6a65cda - rustc_errors::HandlerInner::bug::hf98d0be0ebba3966
  17:     0x7fc0c6a65790 - rustc_errors::Handler::bug::h04eb0f7808456322
  18:     0x7fc0c69c233c - rustc_middle::ty::context::tls::with_opt::hde5a02b3e340c168
  19:     0x7fc0c69c2540 - rustc_middle::util::bug::opt_span_bug_fmt::h9a28451e10b9fa93
  20:     0x7fc0c69c24b6 - rustc_middle::util::bug::bug_fmt::h23a56cbc4ca6dee5
  21:     0x7fc0c735cfaa - rustc_infer::infer::InferCtxtBuilder::enter::h2c875bb32a972d15
  22:     0x7fc0c73b5ef7 - rustc_trait_selection::traits::codegen::codegen_fulfill_obligation::h64001017f09350a7
  23:     0x7fc0c7ab8900 - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h15dacd4ce886ebae
  24:     0x7fc0c7b6a225 - rustc_data_structures::stack::ensure_sufficient_stack::hd63598e46c5cd730
  25:     0x7fc0c70eacba - rustc_query_system::query::plumbing::get_query_impl::h5771d252c00e96d7
  26:     0x7fc0c71627f2 - <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::codegen_fulfill_obligation::ha77cd79506ae5449
  27:     0x7fc0c6d77333 - rustc_ty_utils::instance::inner_resolve_instance::h64355d6972112dfe
  28:     0x7fc0c6d76186 - rustc_ty_utils::instance::resolve_instance::h99586070619f4be5
  29:     0x7fc0c7ac4b3e - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h5a353927bfbbe82e
  30:     0x7fc0c7b5f464 - rustc_data_structures::stack::ensure_sufficient_stack::h12f961eef1da38a0
  31:     0x7fc0c710eadb - rustc_query_system::query::plumbing::get_query_impl::hefa4374c8aca5d4c
  32:     0x7fc0c7163f45 - <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::resolve_instance::h37b1745f8a1fae47
  33:     0x7fc0c74aaa74 - rustc_middle::ty::instance::Instance::resolve_opt_const_arg::ha9dd19d17d2fa702
  34:     0x7fc0c74a9fe9 - rustc_middle::ty::instance::Instance::resolve::h3c499c49724ee011
  35:     0x7fc0c70d1fd0 - <rustc_mir::monomorphize::collector::MirNeighborCollector as rustc_middle::mir::visit::Visitor>::visit_terminator::h992a7e10a89b7b17
  36:     0x7fc0c70d4cfc - rustc_mir::monomorphize::collector::collect_neighbours::h5a3f80fec8cd8ab1
  37:     0x7fc0c70cf30d - rustc_mir::monomorphize::collector::collect_items_rec::h44c2beac1ba7820d
  38:     0x7fc0c70cf45a - rustc_mir::monomorphize::collector::collect_items_rec::h44c2beac1ba7820d
  39:     0x7fc0c70ce413 - rustc_mir::monomorphize::collector::collect_crate_mono_items::hd9a6bcfd88bea354
  40:     0x7fc0c6fa65b7 - rustc_mir::monomorphize::partitioning::collect_and_partition_mono_items::h1a9a53fc99b46dc9
  41:     0x7fc0c63da80a - rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps::h1996e29bec96e763
  42:     0x7fc0c63acbcd - rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl::h6c4f76e4f6e71592
  43:     0x7fc0c644f414 - rustc_data_structures::stack::ensure_sufficient_stack::hc1ea62e05a73757d
  44:     0x7fc0c6208996 - rustc_query_system::query::plumbing::force_query_with_job::h5e7331dd38f3e059
  45:     0x7fc0c79dec2d - rustc_query_system::query::plumbing::get_query_impl::h15204a6dd2a7e64a
  46:     0x7fc0c7b22ac6 - <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::collect_and_partition_mono_items::h7c997d6b7c345890
  47:     0x7fc0c75deca8 - rustc_codegen_ssa::base::codegen_crate::he5549afa8d35de5a
  48:     0x7fc0c75fa8ba - <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate::h249f326ee2c13441
  49:     0x7fc0c757ac15 - rustc_interface::passes::QueryContext::enter::hd50f2d8d11038ed6
  50:     0x7fc0c7572a56 - rustc_interface::queries::Queries::ongoing_codegen::hca1e84ea243aab86
  51:     0x7fc0c754fe25 - rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter::hfc676051f08a93ae
  52:     0x7fc0c753f21c - rustc_span::with_source_map::h01f7ec78329392f8
  53:     0x7fc0c7550fda - rustc_interface::interface::create_compiler_and_run::h9515a6b09b966b58
  54:     0x7fc0c7543229 - scoped_tls::ScopedKey<T>::set::h8d6a24e36deb1132
  55:     0x7fc0c753f8ea - std::sys_common::backtrace::__rust_begin_short_backtrace::h652864f7c1a77965
  56:     0x7fc0c753eb25 - core::ops::function::FnOnce::call_once{{vtable.shim}}::h9a66d3b50f91b159
  57:     0x7fc0c52ba683 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he2a466339cf4c9af
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/alloc/src/boxed.rs:1636:9
  58:     0x7fc0c52ba683 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h1f2d848478877ebe
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/alloc/src/boxed.rs:1636:9
  59:     0x7fc0c52ba683 - std::sys::unix::thread::Thread::new::thread_start::h12773e412063ea14
                               at /rustc/ae90dcf0207c57c3034f00b07048d63f8b2363c8/library/std/src/sys/unix/thread.rs:91:17
  60:     0x7fc0c51e6450 - start_thread
  61:     0x7fc0c50f4e73 - clone
  62:                0x0 - <unknown>

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 1.56.0-nightly (ae90dcf02 2021-08-09) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [codegen_fulfill_obligation] checking if `std::ops::Fn` fulfills its obligations
#1 [resolve_instance] resolving instance `<[closure@src/main.rs:33:38: 33:44] as std::ops::Fn<((),)>>::call`
#2 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack
error: could not compile `abc`

@rustbot modify labels: -E-needs-mcve

[hellow554]

I think this is a dup of #62529 and should be fixed by #85499

Let's hope it gets merged soon ;)

[jackh726]

Closing as duplicate of #62529