typing for async function pointer to generic function #134817
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heiseish
added
C-bug
rustbot
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|
Reduction for the original error: use std::future::Future;
use std::task::Context;
fn make_context() -> Context<'static> {
todo!()
}
fn do_stuff<F>(mut async_fn: F)
where
F: AsyncFnMut(),
{
let _ = Box::pin(async {
async_fn().await;
})
.as_mut()
.poll(&mut make_context());
}
fn make_fn() -> fn() -> dyn Future<Output = ()> {
todo!()
}
fn main() {
do_stuff(make_fn());
}Going further gives use std::future::Future;
use std::task::Context;
fn make_context() -> Context<'static> {
todo!()
}
fn do_stuff<F>(mut async_fn: F)
where
F: AsyncFnMut(),
{
let _ = Box::pin(async_fn()).as_mut().poll(&mut make_context());
}
fn make_fn() -> fn() -> dyn Future<Output = ()> {
todo!()
}
fn main() {
do_stuff(make_fn());
}and removing the last layer gives use std::future::Future;
fn do_stuff<F>(mut async_fn: F)
where
F: AsyncFnMut(),
{
async_fn();
}
fn make_fn() -> fn() -> dyn Future<Output = ()> {
todo!()
}
fn main() {
do_stuff(make_fn());
} |
//@ compile-flags: --crate-type lib -Clink-dead-code --edition=2021
#![feature(async_closure)]
use std::future::Future;
use std::task::Context;
fn make_context() -> Context<'static> {
todo!()
}
fn do_stuff<F>(mut async_fn: F)
where
F: AsyncFnMut(),
{
let _ = Box::pin(async {
async_fn().await;
})
.as_mut()
.poll(&mut make_context());
}
fn make_fn() -> fn() -> dyn Future<Output = ()> {
todo!()
}
fn main() {
do_stuff(make_fn());
}bisects to #132611 cc @compiler-errors |
|
#132611 just added the |
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when I do it like this #![feature(async_closure)]
#![feature(async_fn_traits)]
use std::ops::AsyncFnMut;
use std::future::Future;
use std::task::Context;
fn make_context() -> Context<'static> {
todo!()
}
fn do_stuff<F>(mut async_fn: F)
where
F: AsyncFnMut(),
{
let _ = Box::pin(async {
async_fn().await;
})
.as_mut()
.poll(&mut make_context());
}
fn make_fn() -> fn() -> dyn Future<Output = ()> {
todo!()
}
fn main() {
do_stuff(make_fn());
}it goes to nightly-2024-02-11 commit[0] 2024-02-09: Auto merge of #120852 - matthiaskrgr:rollup-01pr8gj, r=matthiaskrgr |
saethlin
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rustc --version --verbose:Error output
Backtrace
In
mainfn, the argumentHello::Barto do_stuff requires 2nd parameter to be annotated as compiler will complain about not being able to infer otherwise. I tried to providefn(&mut ()) -> dyn Future<Output = ()>, and it crashes the compiler. The following code works without crashing the compilerThe text was updated successfully, but these errors were encountered: