rust/tests/ui/async-await/async-closures/implements-fnmut.rs

28 lines
646 B
Rust

//@ build-pass
//@ edition: 2021
// Demonstrates that an async closure may implement `FnMut` (not just `async FnMut`!)
// if it has no self-borrows. In this case, `&Ty` is not borrowed from the closure env,
// since it's fine to reborrow it with its original lifetime. See the doc comment on
// `should_reborrow_from_env_of_parent_coroutine_closure` for more detail for when we
// must borrow from the closure env.
#![feature(async_closure)]
fn main() {
hello(&Ty);
}
fn needs_fn_mut<T>(mut x: impl FnMut() -> T) {
x();
}
fn hello(x: &Ty) {
needs_fn_mut(async || { x.hello(); });
}
struct Ty;
impl Ty {
fn hello(&self) {}
}