error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:3:1
   |
LL | async fn foo() {}
   | ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:5:12
   |
LL | fn baz() { async fn foo() {} }
   |            ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:7:1
   |
LL | async fn async_baz() {
   | ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:8:5
   |
LL |     async fn bar() {}
   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:14:5
   |
LL |     async fn foo() {}
   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:18:5
   |
LL |     async fn foo() {}
   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:37:9
   |
LL |         async fn bar() {}
   |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:27:9
   |
LL |         async fn foo() {}
   |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0670]: `async fn` is not permitted in Rust 2015
  --> $DIR/edition-deny-async-fns-2015.rs:32:13
   |
LL |             async fn bar() {}
   |             ^^^^^ to use `async fn`, switch to Rust 2018 or later
   |
   = help: pass `--edition 2021` to `rustc`
   = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0706]: functions in traits cannot be declared `async`
  --> $DIR/edition-deny-async-fns-2015.rs:18:5
   |
LL |     async fn foo() {}
   |     -----^^^^^^^^^
   |     |
   |     `async` because of this
   |
   = note: `async` trait functions are not currently supported
   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable

error[E0308]: mismatched types
  --> $DIR/edition-deny-async-fns-2015.rs:18:20
   |
LL |     async fn foo() {}
   |                    ^^ expected associated type, found opaque type
   |
  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
   |
LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
   |                                           ------------------------------- the found opaque type
   |
   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/edition-deny-async-fns-2015.rs:18:20>)
                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)

error: aborting due to 11 previous errors

Some errors have detailed explanations: E0308, E0670, E0706.
For more information about an error, try `rustc --explain E0308`.