| error[E0277]: `impl Sized` cannot be sent between threads safely | 
 |   --> $DIR/check-wf-on-non-defaulted-rpitit.rs:4:17 | 
 |    | | 
 | LL |     fn bar() -> Wrapper<impl Sized>; | 
 |    |                 ^^^^^^^^^^^^^^^^^^^ `impl Sized` cannot be sent between threads safely | 
 |    | | 
 |    = help: the trait `Send` is not implemented for `impl Sized` | 
 | note: required by a bound in `Wrapper` | 
 |   --> $DIR/check-wf-on-non-defaulted-rpitit.rs:1:19 | 
 |    | | 
 | LL | struct Wrapper<G: Send>(G); | 
 |    |                   ^^^^ required by this bound in `Wrapper` | 
 |  | 
 | error: aborting due to 1 previous error | 
 |  | 
 | For more information about this error, try `rustc --explain E0277`. |