ICE: index out of bounds, instrument coverage

[matthiaskrgr]

auto-reduced (treereduce-rust):

use std::future::Future;

pub fn block_on<T>(fut: impl Future<Output = T>) -> T {}

async fn call_once(f: impl async FnOnce(DropMe)) {
    f(DropMe("world")).await;
}

struct DropMe(&'static str);

pub fn main() {
    block_on(async {
        let async_closure = async move |a: DropMe| {};
        call_once(async_closure).await;
    });
}

original:

#![feature(async_closure, noop_waker, async_fn_traits)]

use std::future::Future;
use std::pin::pin;
use std::task::*;

pub fn block_on<T>(fut: impl Future<Output = T>) -> T {
    let mut fut = pin!(fut);
    let ctx = &mut Context::from_waker(Waker::noop());

    loop {
        match fut.as_mut().poll(ctx) {
            Poll::Pending => {}
            Poll::Ready(t) => break t,
        }
    }
}

async fn call_once(f: impl async FnOnce(DropMe)) {
    f(DropMe("world")).await;
}

#[derive(Debug)]
struct DropMe(&'static str);

impl Drop for DropMe {
    fn drop(&mut self) {
        println!("{}", self.0);
    }
}

pub fn main() {
    block_on(async {
        let b = DropMe("hello");
        let async_closure = async move |a: DropMe| {
            println!("{a:?} {b:?}");
        };
        call_once(async_closure).await;
    });
}

Version information

rustc 1.83.0-nightly (888523978 2024-10-03)
binary: rustc
commit-hash: 8885239786c9efe5c6077de65536a5e092e34a55
commit-date: 2024-10-03
host: x86_64-unknown-linux-gnu
release: 1.83.0-nightly
LLVM version: 19.1.0

Command: /home/matthias/.rustup/toolchains/master/bin/rustc -Cinstrument-coverage --edition=2018

Program output

``` error[E0658]: async closures are unstable --> /tmp/icemaker_global_tempdir.oaNujPif49Om/rustc_testrunner_tmpdir_reporting.OG1eQwd5cy9L/mvce.rs:5:28 | 5 | async fn call_once(f: impl async FnOnce(DropMe)) { | ^^^^^ | = note: see issue #62290 for more information = help: add `#![feature(async_closure)]` to the crate attributes to enable = note: this compiler was built on 2024-10-03; consider upgrading it if it is out of date = help: to use an async block, remove the `||`: `async {` error[E0658]: async closures are unstable --> /tmp/icemaker_global_tempdir.oaNujPif49Om/rustc_testrunner_tmpdir_reporting.OG1eQwd5cy9L/mvce.rs:13:29 | 13 | let async_closure = async move |a: DropMe| {}; | ^^^^^ | = note: see issue #62290 for more information = help: add `#![feature(async_closure)]` to the crate attributes to enable = note: this compiler was built on 2024-10-03; consider upgrading it if it is out of date = help: to use an async block, remove the `||`: `async {` error[E0658]: use of unstable library feature 'async_closure' --> /tmp/icemaker_global_tempdir.oaNujPif49Om/rustc_testrunner_tmpdir_reporting.OG1eQwd5cy9L/mvce.rs:5:34 | 5 | async fn call_once(f: impl async FnOnce(DropMe)) { | ^^^^^^^^^^^^^^ | = note: see issue #62290 for more information = help: add `#![feature(async_closure)]` to the crate attributes to enable = note: this compiler was built on 2024-10-03; consider upgrading it if it is out of date error[E0308]: mismatched types --> /tmp/icemaker_global_tempdir.oaNujPif49Om/rustc_testrunner_tmpdir_reporting.OG1eQwd5cy9L/mvce.rs:3:53 | 3 | pub fn block_on(fut: impl Future

) -> T {} | -------- - ^ expected type parameter `T`, found `()` | | | | | expected this type parameter | implicitly returns `()` as its body has no tail or `return` expression | = note: expected type parameter `T` found unit type `()` warning: unused variable: `a` --> /tmp/icemaker_global_tempdir.oaNujPif49Om/rustc_testrunner_tmpdir_reporting.OG1eQwd5cy9L/mvce.rs:13:41 | 13 | let async_closure = async move |a: DropMe| {}; | ^ help: if this is intentional, prefix it with an underscore: `_a` | = note: `#[warn(unused_variables)]` on by default thread 'rustc' panicked at /rustc/8885239786c9efe5c6077de65536a5e092e34a55/compiler/rustc_middle/src/hir/mod.rs:167:84: index out of bounds: the len is 18 but the index is 18 stack backtrace: 0: 0x7beaa312055a - ::fmt::hb592cf74724b425e 1: 0x7beaa3803426 - core::fmt::write::hf5d6063860bea70f 2: 0x7beaa49e0e51 - std::io::Write::write_fmt::hffd3de1a22689c3f 3: 0x7beaa31203b2 - std::sys::backtrace::BacktraceLock::print::h63270fe5b69f528d 4: 0x7beaa3122886 - std::panicking::default_hook::{{closure}}::heab8066707c891e2 5: 0x7beaa31226d0 - std::panicking::default_hook::h04bff44e2827e0a1 6: 0x7beaa21d718f - std[a04536816f5670be]::panicking::update_hook::>::{closure#0} 7: 0x7beaa3122f98 - std::panicking::rust_panic_with_hook::h8c4b4462dd073994 8: 0x7beaa3122d6a - std::panicking::begin_panic_handler::{{closure}}::h3e8c389e20c1d0de 9: 0x7beaa3120a09 - std::sys::backtrace::__rust_end_short_backtrace::h8ff57cfb18e819fb 10: 0x7beaa3122a2c - rust_begin_unwind 11: 0x7bea9fec29e0 - core::panicking::panic_fmt::h1ebaebc26e6fd1b2 12: 0x7beaa19291ab - core::panicking::panic_bounds_check::hc44d35339120f09a 13: 0x7beaa3b2dd08 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 14: 0x7beaa3b2d31b - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 15: 0x7beaa3b2ce4f - rustc_query_impl[a29eb790b8655a40]::query_impl::local_def_id_to_hir_id::get_query_non_incr::__rust_end_short_backtrace 16: 0x7beaa295ea8c - rustc_middle[5107f05ab9282e45]::query::plumbing::query_get_at::>> 17: 0x7beaa29e35f6 - rustc_mir_transform[d3e5830c4043327a]::coverage::query::coverage_attr_on 18: 0x7beaa2c2d297 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 19: 0x7beaa4207ba9 - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 20: 0x7beaa2c367c7 - rustc_query_impl[a29eb790b8655a40]::query_impl::coverage_attr_on::get_query_non_incr::__rust_end_short_backtrace 21: 0x7beaa295e8ff - rustc_middle[5107f05ab9282e45]::query::plumbing::query_get_at::>> 22: 0x7beaa29e35b6 - rustc_mir_transform[d3e5830c4043327a]::coverage::query::is_eligible_for_coverage 23: 0x7beaa29e878e - ::run_pass 24: 0x7beaa0c88d94 - rustc_mir_transform[d3e5830c4043327a]::mir_promoted 25: 0x7beaa3c72152 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 26: 0x7beaa3c72421 - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 27: 0x7beaa47ba350 - rustc_query_impl[a29eb790b8655a40]::query_impl::mir_promoted::get_query_non_incr::__rust_end_short_backtrace 28: 0x7beaa4cc2c0d - rustc_middle[5107f05ab9282e45]::query::plumbing::query_get_at::>>.cold 29: 0x7beaa2a34aca - rustc_mir_transform[d3e5830c4043327a]::coroutine::mir_coroutine_witnesses 30: 0x7beaa2c2d8b2 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 31: 0x7beaa382f5ae - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 32: 0x7beaa2c35d0e - rustc_query_impl[a29eb790b8655a40]::query_impl::mir_coroutine_witnesses::get_query_non_incr::__rust_end_short_backtrace 33: 0x7beaa40fe2f4 - rustc_mir_transform[d3e5830c4043327a]::mir_drops_elaborated_and_const_checked 34: 0x7beaa40fd595 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 35: 0x7beaa3b2d0fa - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 36: 0x7beaa3b2caa5 - rustc_query_impl[a29eb790b8655a40]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace 37: 0x7beaa3a45b6a - rustc_mir_transform[d3e5830c4043327a]::optimized_mir 38: 0x7beaa3a442a1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 39: 0x7beaa382f5ae - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 40: 0x7beaa382eb5f - rustc_query_impl[a29eb790b8655a40]::query_impl::optimized_mir::get_query_non_incr::__rust_end_short_backtrace 41: 0x7beaa3e29f01 - rustc_middle[5107f05ab9282e45]::query::plumbing::query_get_at::>> 42: 0x7beaa2848a5e - ::coroutine_layout 43: 0x7beaa3ec8ad9 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached 44: 0x7beaa3eb9646 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 45: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 46: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 47: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 48: 0x7beaa3eb763c - , rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached::{closure#13}>>, core[cb6fe1446f4e495e]::result::Result> as core[cb6fe1446f4e495e]::iter::traits::iterator::Iterator>::next 49: 0x7beaa3ebe0d0 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached 50: 0x7beaa3eb9646 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 51: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 52: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 53: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 54: 0x7beaa3eb79bd - , rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached::{closure#13}>>, core[cb6fe1446f4e495e]::result::Result> as core[cb6fe1446f4e495e]::iter::traits::iterator::Iterator>::next 55: 0x7beaa3ebe0d0 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached 56: 0x7beaa3eb9646 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 57: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 58: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 59: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 60: 0x7beaa3eb511d - rustc_middle[5107f05ab9282e45]::query::plumbing::query_get_at::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>> 61: 0x7beaa3eb99f2 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 62: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 63: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 64: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 65: 0x7beaa3eb511d - rustc_middle[5107f05ab9282e45]::query::plumbing::query_get_at::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>> 66: 0x7beaa309b19a - ::spanned_layout_of 67: 0x7beaa308717e - >, rustc_ty_utils[40b1ed103802e44]::layout::coroutine_layout::{closure#2}>, core[cb6fe1446f4e495e]::iter::sources::once::Once, &rustc_middle[5107f05ab9282e45]::ty::layout::LayoutError>>>, core[cb6fe1446f4e495e]::iter::adapters::map::Map, rustc_ty_utils[40b1ed103802e44]::layout::coroutine_layout::{closure#1}>>>, core[cb6fe1446f4e495e]::result::Result> as core[cb6fe1446f4e495e]::iter::traits::iterator::Iterator>::next 68: 0x7beaa3ec9199 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached 69: 0x7beaa3eb9646 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 70: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 71: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 72: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 73: 0x7beaa3eb763c - , rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached::{closure#13}>>, core[cb6fe1446f4e495e]::result::Result> as core[cb6fe1446f4e495e]::iter::traits::iterator::Iterator>::next 74: 0x7beaa3ebe0d0 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached 75: 0x7beaa3eb9646 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 76: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 77: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 78: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 79: 0x7beaa3eb79bd - , rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached::{closure#13}>>, core[cb6fe1446f4e495e]::result::Result> as core[cb6fe1446f4e495e]::iter::traits::iterator::Iterator>::next 80: 0x7beaa3ebe0d0 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached 81: 0x7beaa3eb9646 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 82: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 83: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 84: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 85: 0x7beaa3eb511d - rustc_middle[5107f05ab9282e45]::query::plumbing::query_get_at::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>> 86: 0x7beaa309b19a - ::spanned_layout_of 87: 0x7beaa308717e - >, rustc_ty_utils[40b1ed103802e44]::layout::coroutine_layout::{closure#2}>, core[cb6fe1446f4e495e]::iter::sources::once::Once, &rustc_middle[5107f05ab9282e45]::ty::layout::LayoutError>>>, core[cb6fe1446f4e495e]::iter::adapters::map::Map, rustc_ty_utils[40b1ed103802e44]::layout::coroutine_layout::{closure#1}>>>, core[cb6fe1446f4e495e]::result::Result> as core[cb6fe1446f4e495e]::iter::traits::iterator::Iterator>::next 88: 0x7beaa3ec9199 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of_uncached 89: 0x7beaa3eb9646 - rustc_ty_utils[40b1ed103802e44]::layout::layout_of 90: 0x7beaa3eb95d1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 91: 0x7beaa3eb884d - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::, rustc_middle[5107f05ab9282e45]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 92: 0x7beaa3eb84e7 - rustc_query_impl[a29eb790b8655a40]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace 93: 0x7beaa0dcd2ad - ::run_lint 94: 0x7beaa3806acc - rustc_mir_transform[d3e5830c4043327a]::run_analysis_to_runtime_passes 95: 0x7beaa40fdc52 - rustc_mir_transform[d3e5830c4043327a]::mir_drops_elaborated_and_const_checked 96: 0x7beaa40fd595 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 97: 0x7beaa3b2d0fa - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 98: 0x7beaa3b2caa5 - rustc_query_impl[a29eb790b8655a40]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace 99: 0x7beaa3b26cd2 - rustc_interface[ec6f4c50e1aefefe]::passes::run_required_analyses 100: 0x7beaa463d41e - rustc_interface[ec6f4c50e1aefefe]::passes::analysis 101: 0x7beaa463d3f1 - rustc_query_impl[a29eb790b8655a40]::plumbing::__rust_begin_short_backtrace::> 102: 0x7beaa46d772e - rustc_query_system[fcc792b70dcbd9a8]::query::plumbing::try_execute_query::>, false, false, false>, rustc_query_impl[a29eb790b8655a40]::plumbing::QueryCtxt, false> 103: 0x7beaa46d740f - rustc_query_impl[a29eb790b8655a40]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace 104: 0x7beaa454051e - rustc_interface[ec6f4c50e1aefefe]::interface::run_compiler::, rustc_driver_impl[d8d06b747560f99c]::run_compiler::{closure#0}>::{closure#1} 105: 0x7beaa4624810 - std[a04536816f5670be]::sys::backtrace::__rust_begin_short_backtrace::, rustc_driver_impl[d8d06b747560f99c]::run_compiler::{closure#0}>::{closure#1}, core[cb6fe1446f4e495e]::result::Result<(), rustc_span[3db820fc671a7841]::ErrorGuaranteed>>::{closure#0}, core[cb6fe1446f4e495e]::result::Result<(), rustc_span[3db820fc671a7841]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[cb6fe1446f4e495e]::result::Result<(), rustc_span[3db820fc671a7841]::ErrorGuaranteed>> 106: 0x7beaa4624ed7 - <::spawn_unchecked_, rustc_driver_impl[d8d06b747560f99c]::run_compiler::{closure#0}>::{closure#1}, core[cb6fe1446f4e495e]::result::Result<(), rustc_span[3db820fc671a7841]::ErrorGuaranteed>>::{closure#0}, core[cb6fe1446f4e495e]::result::Result<(), rustc_span[3db820fc671a7841]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[cb6fe1446f4e495e]::result::Result<(), rustc_span[3db820fc671a7841]::ErrorGuaranteed>>::{closure#1} as core[cb6fe1446f4e495e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 107: 0x7beaa4625dc1 - std::sys::pal::unix::thread::Thread::new::thread_start::heca97faccc80f502 108: 0x7bea9eaa339d - 109: 0x7bea9eb2849c - 110: 0x0 - 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: rustc 1.83.0-nightly (888523978 2024-10-03) running on x86_64-unknown-linux-gnu note: compiler flags: -C instrument-coverage -Z dump-mir-dir=dir query stack during panic: #0 [local_def_id_to_hir_id] getting HIR ID of `main::{closure#0}::{closure#0}::{closure#1}` #1 [coverage_attr_on] checking for `#[coverage(..)]` on `main::{closure#0}::{closure#0}::{closure#1}` end of query stack error: aborting due to 4 previous errors; 1 warning emitted Some errors have detailed explanations: E0308, E0658. For more information about an error, try `rustc --explain E0308`. ```

@rustbot label +F-async_closure +F-noop_waker +F-async_fn_traits

[traviscross]

@rustbot labels -needs-triage +AsyncAwait-Triaged

Interesting, as always, @matthiaskrgr. Thanks for the report.

[ranger-ross]

Bisected to nightly-2024-09-18,

Regression in 41a3e06d0e0b1104e4adf3332f8c0876bec14b00 from #130201

[traviscross]

cc @compiler-errors given bisection.

[compiler-errors]

I'll look

[compiler-errors]

side note, @traviscross: in async triage, if you're gonna remove the needs-triage label please consider adding the relevant F- labels too