Invalid bound suggestion for argument-position impl trait

[Aaron1011]

The following code:

fn is_send<T: Send>(val: T) {}

fn use_impl_sync(val: impl Sync) {
    is_send(val);
}

gives the following error:

error[E0277]: `impl Sync` cannot be sent between threads safely
 --> src/lib.rs:4:5
  |
1 | fn is_send<T: Send>(val: T) {}
  | --------------------------- required by `is_send`
...
4 |     is_send(val);
  |     ^^^^^^^ `impl Sync` cannot be sent between threads safely
  |
  = help: the trait `std::marker::Send` is not implemented for `impl Sync`
  = help: consider adding a `where impl Sync: std::marker::Send` bound

The suggestion where impl Sync: std::marker::Send is invalid: it should be impl Sync + Send

[estebank]

Current output, only minor changes:

error[E0277]: `impl Sync` cannot be sent between threads safely
 --> src/lib.rs:4:13
  |
1 | fn is_send<T: Send>(val: T) {}
  |    -------    ---- required by this bound in `is_send`
...
4 |     is_send(val);
  |             ^^^ `impl Sync` cannot be sent between threads safely
  |
  = help: the trait `std::marker::Send` is not implemented for `impl Sync`
  = help: consider adding a `where impl Sync: std::marker::Send` bound