//@ edition:2015 async fn foo() {} //~ ERROR `async fn` is not permitted in Rust 2015 fn baz() { async fn foo() {} } //~ ERROR `async fn` is not permitted in Rust 2015 async fn async_baz() { //~ ERROR `async fn` is not permitted in Rust 2015 async fn bar() {} //~ ERROR `async fn` is not permitted in Rust 2015 } struct Foo {} impl Foo { async fn foo() {} //~ ERROR `async fn` is not permitted in Rust 2015 } trait Bar { async fn foo() {} //~ ERROR `async fn` is not permitted in Rust 2015 } fn main() { macro_rules! accept_item { ($x:item) => {} } accept_item! { async fn foo() {} //~ ERROR `async fn` is not permitted in Rust 2015 } accept_item! { impl Foo { async fn bar() {} //~ ERROR `async fn` is not permitted in Rust 2015 } } let inside_closure = || { async fn bar() {} //~ ERROR `async fn` is not permitted in Rust 2015 }; }