error: future cannot be sent between threads safely
  --> $DIR/issue-68112.rs:34:5
   |
LL |     require_send(send_fut);
   |     ^^^^^^^^^^^^^^^^^^^^^^ future created by async block is not `Send`
   |
   = help: the trait `Sync` is not implemented for `RefCell<i32>`, which is required by `{async block@$DIR/issue-68112.rs:29:20: 29:25}: Send`
   = note: if you want to do aliasing and mutation between multiple threads, use `std::sync::RwLock` instead
note: future is not `Send` as it awaits another future which is not `Send`
  --> $DIR/issue-68112.rs:31:17
   |
LL |         let _ = non_send_fut.await;
   |                 ^^^^^^^^^^^^ await occurs here on type `impl Future<Output = Arc<RefCell<i32>>>`, which is not `Send`
note: required by a bound in `require_send`
  --> $DIR/issue-68112.rs:11:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: future cannot be sent between threads safely
  --> $DIR/issue-68112.rs:43:5
   |
LL |     require_send(send_fut);
   |     ^^^^^^^^^^^^^^^^^^^^^^ future created by async block is not `Send`
   |
   = help: the trait `Sync` is not implemented for `RefCell<i32>`, which is required by `{async block@$DIR/issue-68112.rs:39:20: 39:25}: Send`
   = note: if you want to do aliasing and mutation between multiple threads, use `std::sync::RwLock` instead
note: future is not `Send` as it awaits another future which is not `Send`
  --> $DIR/issue-68112.rs:40:17
   |
LL |         let _ = make_non_send_future1().await;
   |                 ^^^^^^^^^^^^^^^^^^^^^^^ await occurs here on type `impl Future<Output = Arc<RefCell<i32>>>`, which is not `Send`
note: required by a bound in `require_send`
  --> $DIR/issue-68112.rs:11:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error[E0277]: `RefCell<i32>` cannot be shared between threads safely
  --> $DIR/issue-68112.rs:62:5
   |
LL |     require_send(send_fut);
   |     ^^^^^^^^^^^^^^^^^^^^^^ `RefCell<i32>` cannot be shared between threads safely
   |
   = help: the trait `Sync` is not implemented for `RefCell<i32>`, which is required by `{async block@$DIR/issue-68112.rs:57:20: 57:25}: Send`
   = note: if you want to do aliasing and mutation between multiple threads, use `std::sync::RwLock` instead
   = note: required for `Arc<RefCell<i32>>` to implement `Send`
note: required because it's used within this `async` fn body
  --> $DIR/issue-68112.rs:47:31
   |
LL |   async fn ready2<T>(t: T) -> T {
   |  _______________________________^
LL | |     t
LL | | }
   | |_^
note: required because it appears within the type `impl Future<Output = Arc<RefCell<i32>>>`
  --> $DIR/issue-68112.rs:50:31
   |
LL | fn make_non_send_future2() -> impl Future<Output = Arc<RefCell<i32>>> {
   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: required because it's used within this `async` block
  --> $DIR/issue-68112.rs:57:20
   |
LL |     let send_fut = async {
   |                    ^^^^^
note: required by a bound in `require_send`
  --> $DIR/issue-68112.rs:11:25
   |
LL | fn require_send(_: impl Send) {}
   |                         ^^^^ required by this bound in `require_send`

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0277`.