error: future cannot be sent between threads safely
  --> $DIR/issue-68112.rs:33:5
   |
LL | fn require_send(_: impl Send) {}
   |    ------------         ---- required by this bound in `require_send`
...
LL |     require_send(send_gen);
   |     ^^^^^^^^^^^^ generator is not `Send`
   |
   = help: the trait `std::marker::Sync` is not implemented for `std::cell::RefCell<i32>`
note: future is not `Send` as this value is used across an yield
  --> $DIR/issue-68112.rs:31:9
   |
LL |         let _non_send_gen = make_non_send_generator();
   |             ------------- has type `impl std::ops::Generator`
LL |         yield;
   |         ^^^^^ yield occurs here, with `_non_send_gen` maybe used later
LL |     };
   |     - `_non_send_gen` is later dropped here

error[E0277]: `std::cell::RefCell<i32>` cannot be shared between threads safely
  --> $DIR/issue-68112.rs:52:5
   |
LL | fn require_send(_: impl Send) {}
   |    ------------         ---- required by this bound in `require_send`
...
LL |     require_send(send_gen);
   |     ^^^^^^^^^^^^ `std::cell::RefCell<i32>` cannot be shared between threads safely
   |
   = help: the trait `std::marker::Sync` is not implemented for `std::cell::RefCell<i32>`
   = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Arc<std::cell::RefCell<i32>>`
   = note: required because it appears within the type `[generator@$DIR/issue-68112.rs:38:5: 41:6 t:std::sync::Arc<std::cell::RefCell<i32>> {()}]`
   = note: required because it appears within the type `impl std::ops::Generator`
   = note: required because it appears within the type `impl std::ops::Generator`
   = note: required because it appears within the type `{impl std::ops::Generator, ()}`
   = note: required because it appears within the type `[generator@$DIR/issue-68112.rs:48:20: 51:6 {impl std::ops::Generator, ()}]`

error: aborting due to 2 previous errors

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