typing for async function pointer to generic function #134817
Open
Description
Code
#![feature(async_trait_bounds)]
use std::future::Future;
use std::{process::Output, time::Duration};
use tokio::runtime::Runtime;
pub enum Hello<IF, LF> {
Foo(IF, LF, u64),
Bar(IF),
}
fn do_stuff<IF, LF, R>(hello: Hello<IF, LF>)
where
IF: async FnOnce() -> R + Send + 'static,
LF: async FnMut(&mut R) + Send + 'static,
{
match hello {
Hello::Foo(init_fn, mut loop_fn, sleep_dur) => {
let rt = Runtime::new().expect("cannot build async runtime");
rt.block_on(async {
let mut resources = init_fn().await;
loop {
loop_fn(&mut resources).await;
tokio::time::sleep(Duration::new(sleep_dur, 0)).await;
}
});
}
_ => todo!(),
}
}
fn main() {
do_stuff(Hello::Bar::<_, fn(&mut ()) -> dyn Future<Output = ()>>(
async || {
tokio::time::sleep(Duration::new(1, 0)).await;
},
));
}Meta
rustc --version --verbose:
rustc 1.85.0-nightly (917bfa784 2024-12-26)
binary: rustc
commit-hash: 917bfa78478cbcc77406e5ea37b24c3eedefacf4
commit-date: 2024-12-26
host: x86_64-unknown-linux-gnu
release: 1.85.0-nightly
LLVM version: 19.1.6
Error output
❯ cargo build
Compiling rustc_panic v0.1.0 (/home/heiseish/Projects/open_source/rustc_panic)
warning: unused import: `process::Output`
--> src/main.rs:4:11
|
4 | use std::{process::Output, time::Duration};
| ^^^^^^^^^^^^^^^
|
= note: `#[warn(unused_imports)]` on by default
error: internal compiler error: compiler/rustc_middle/src/ty/instance.rs:585:21: failed to resolve instance for <dyn Future<Output = ()> as IntoFuture>::into_future
--> src/main.rs:22:45
|
22 | loop_fn(&mut resources).await;
| ^^^^^
thread 'rustc' panicked at compiler/rustc_middle/src/ty/instance.rs:585:21:
Box<dyn Any>
Backtrace
stack backtrace:
0: 0x765e7d6bdaea - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h1d0ee148a2de4294
1: 0x765e7de138a6 - core::fmt::write::hf11d8a23ef99d1ee
2: 0x765e7ed3ad11 - std::io::Write::write_fmt::h5552168af656165a
3: 0x765e7d6bd942 - std::sys::backtrace::BacktraceLock::print::h796c6a285a4725f9
4: 0x765e7d6bfe3a - std::panicking::default_hook::{{closure}}::h325be6bc905d0158
5: 0x765e7d6bfc83 - std::panicking::default_hook::h4be7e4f43af8c145
6: 0x765e7c82cfd8 - std[576b7bfd2cf774ca]::panicking::update_hook::<alloc[f786130172a2e500]::boxed::Box<rustc_driver_impl[54dd4ff5a6961956]::install_ice_hook::{closure#1}>>::{closure#0}
7: 0x765e7d6c05f8 - std::panicking::rust_panic_with_hook::ha28ff0db34716bf7
8: 0x765e7c865ae1 - std[576b7bfd2cf774ca]::panicking::begin_panic::<rustc_errors[400d740334a151d5]::ExplicitBug>::{closure#0}
9: 0x765e7c85acc6 - std[576b7bfd2cf774ca]::sys::backtrace::__rust_end_short_backtrace::<std[576b7bfd2cf774ca]::panicking::begin_panic<rustc_errors[400d740334a151d5]::ExplicitBug>::{closure#0}, !>
10: 0x765e7c8576d9 - std[576b7bfd2cf774ca]::panicking::begin_panic::<rustc_errors[400d740334a151d5]::ExplicitBug>
11: 0x765e7c86fa41 - <rustc_errors[400d740334a151d5]::diagnostic::BugAbort as rustc_errors[400d740334a151d5]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
12: 0x765e7cdc98cc - <rustc_errors[400d740334a151d5]::DiagCtxtHandle>::span_bug::<rustc_span[5ca00d45d35c07fd]::span_encoding::Span, alloc[f786130172a2e500]::string::String>
13: 0x765e7ce4e6d7 - rustc_middle[b909414d40cb41fe]::util::bug::opt_span_bug_fmt::<rustc_span[5ca00d45d35c07fd]::span_encoding::Span>::{closure#0}
14: 0x765e7ce3376a - rustc_middle[b909414d40cb41fe]::ty::context::tls::with_opt::<rustc_middle[b909414d40cb41fe]::util::bug::opt_span_bug_fmt<rustc_span[5ca00d45d35c07fd]::span_encoding::Span>::{closure#0}, !>::{closure#0}
15: 0x765e7ce335fb - rustc_middle[b909414d40cb41fe]::ty::context::tls::with_context_opt::<rustc_middle[b909414d40cb41fe]::ty::context::tls::with_opt<rustc_middle[b909414d40cb41fe]::util::bug::opt_span_bug_fmt<rustc_span[5ca00d45d35c07fd]::span_enco
ding::Span>::{closure#0}, !>::{closure#0}, !>
16: 0x765e7b34dab7 - rustc_middle[b909414d40cb41fe]::util::bug::span_bug_fmt::<rustc_span[5ca00d45d35c07fd]::span_encoding::Span>
17: 0x765e7e4853cc - <rustc_middle[b909414d40cb41fe]::ty::instance::Instance>::expect_resolve
18: 0x765e7b5b988e - rustc_monomorphize[599c2cf5d481a779]::collector::items_of_instance
19: 0x765e7e23ccd0 - rustc_query_impl[6b10eca21df4ac6c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[6b10eca21df4ac6c]::query_impl::items_of_instance::dynamic_query::{closure#2}::{closure#0}, rustc_middle[b909414d40cb41fe]::query::era
se::Erased<[u8; 32usize]>>
20: 0x765e7e23ac45 - rustc_query_system[913920e265418f40]::query::plumbing::try_execute_query::<rustc_query_impl[6b10eca21df4ac6c]::DynamicConfig<rustc_query_system[913920e265418f40]::query::caches::DefaultCache<(rustc_middle[b909414d40cb41fe]::ty:
:instance::Instance, rustc_middle[b909414d40cb41fe]::mir::mono::CollectionMode), rustc_middle[b909414d40cb41fe]::query::erase::Erased<[u8; 32usize]>>, false, false, false>, rustc_query_impl[6b10eca21df4ac6c]::plumbing::QueryCtxt, true>
21: 0x765e7e2398e4 - rustc_query_impl[6b10eca21df4ac6c]::query_impl::items_of_instance::get_query_incr::__rust_end_short_backtrace
22: 0x765e7e238f4c - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec::{closure#0} 16:41:22 [10/57]
23: 0x765e7ef1774e - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
24: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
25: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
26: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
27: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
28: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
29: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
30: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
31: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
32: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
33: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
34: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
35: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
36: 0x765e7ef18093 - rustc_monomorphize[599c2cf5d481a779]::collector::collect_items_rec
37: 0x765e7e3495ea - rustc_monomorphize[599c2cf5d481a779]::partitioning::collect_and_partition_mono_items
38: 0x765e7e348756 - rustc_query_impl[6b10eca21df4ac6c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[6b10eca21df4ac6c]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2}::{closure#0}, rustc_middle[b909414d40cb41
fe]::query::erase::Erased<[u8; 24usize]>>
39: 0x765e7e348727 - <rustc_query_impl[6b10eca21df4ac6c]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2} as core[c1b327b82653d6c1]::ops::function::FnOnce<(rustc_middle[b909414d40cb41fe]::ty::context::TyCtxt, ())>>::call_on
ce
40: 0x765e7ed467d6 - rustc_query_system[913920e265418f40]::query::plumbing::try_execute_query::<rustc_query_impl[6b10eca21df4ac6c]::DynamicConfig<rustc_query_system[913920e265418f40]::query::caches::SingleCache<rustc_middle[b909414d40cb41fe]::query
::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[6b10eca21df4ac6c]::plumbing::QueryCtxt, true>
41: 0x765e7ed45f89 - rustc_query_impl[6b10eca21df4ac6c]::query_impl::collect_and_partition_mono_items::get_query_incr::__rust_end_short_backtrace
42: 0x765e7edcde70 - <rustc_codegen_llvm[cdec4fa7cea21c2d]::LlvmCodegenBackend as rustc_codegen_ssa[8d2a18b1528a2a1b]::traits::backend::CodegenBackend>::codegen_crate
43: 0x765e7edd7e64 - <rustc_interface[c17f2d9f8580ef84]::queries::Linker>::codegen_and_build_linker
44: 0x765e7ef0d152 - rustc_interface[c17f2d9f8580ef84]::passes::create_and_enter_global_ctxt::<core[c1b327b82653d6c1]::option::Option<rustc_interface[c17f2d9f8580ef84]::queries::Linker>, rustc_driver_impl[54dd4ff5a6961956]::run_compiler::{closure#0
}::{closure#2}>::{closure#2}::{closure#0}
45: 0x765e7ed69956 - rustc_interface[c17f2d9f8580ef84]::interface::run_compiler::<(), rustc_driver_impl[54dd4ff5a6961956]::run_compiler::{closure#0}>::{closure#1}
46: 0x765e7ec44011 - std[576b7bfd2cf774ca]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[c17f2d9f8580ef84]::util::run_in_thread_with_globals<rustc_interface[c17f2d9f8580ef84]::util::run_in_thread_pool_with_globals<rustc_interface[
c17f2d9f8580ef84]::interface::run_compiler<(), rustc_driver_impl[54dd4ff5a6961956]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
47: 0x765e7ec444a6 - <<std[576b7bfd2cf774ca]::thread::Builder>::spawn_unchecked_<rustc_interface[c17f2d9f8580ef84]::util::run_in_thread_with_globals<rustc_interface[c17f2d9f8580ef84]::util::run_in_thread_pool_with_globals<rustc_interface[c17f2d9f85
80ef84]::interface::run_compiler<(), rustc_driver_impl[54dd4ff5a6961956]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[c1b327b82653d6c1]::ops::function::FnOnce<()>>::call_once::{shim:v
table#0}
48: 0x765e7ec45a6f - std::sys::pal::unix::thread::Thread::new::thread_start::he1f2589b932bd245
49: 0x765e78e9ca94 - start_thread
at ./nptl/pthread_create.c:447:8
50: 0x765e78f29c3c - clone3
at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78
51: 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: please attach the file at `/home/heiseish/Projects/open_source/rustc_panic/rustc-ice-2024-12-27T08_40_34-90427.txt` to your bug report
note: compiler flags: --crate-type bin -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED]
note: some of the compiler flags provided by cargo are hidden
query stack during panic:
#0 [items_of_instance] collecting items used by `do_stuff::<{async closure@src/main.rs:33:9: 33:17}, for<'a> fn(&'a mut ()) -> dyn core::future::future::Future<Output = ()>, ()>::{closure#0}`
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack
warning: `rustc_panic` (bin "rustc_panic") generated 1 warning (run `cargo fix --bin "rustc_panic"` to apply 1 suggestion)
error: could not compile `rustc_panic` (bin "rustc_panic"); 1 warning emitted
Caused by:
process didn't exit successfully: `/home/heiseish/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc --crate-name rustc_panic --edition=2021 src/main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnost
ic-width=254 --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=26ab0fcf5b8dc6c6 -C extra-filename=-673f8cce13ac8c1d --out-dir /home/heiseish/Projects/o
pen_source/rustc_panic/target/debug/deps -C incremental=/home/heiseish/Projects/open_source/rustc_panic/target/debug/incremental -L dependency=/home/heiseish/Projects/open_source/rustc_panic/target/debug/deps --extern tokio=/home/heiseish/Projects/open_s
ource/rustc_panic/target/debug/deps/libtokio-516589f016b48863.rlib` (exit status: 101)
In main fn, the argument Hello::Bar to do_stuff requires 2nd parameter to be annotated as compiler will complain about not being able to infer otherwise. I tried to provide fn(&mut ()) -> dyn Future<Output = ()>, and it crashes the compiler. The following code works without crashing the compiler
type BoxedFuture<T = ()> = Pin<Box<dyn Future<Output = T>>>;
fn main() {
do_stuff(Hello::Bar::<_, fn(&mut ()) -> BoxedFuture>(
async || {
tokio::time::sleep(Duration::new(1, 0)).await;
},
));
}
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