error[E0277]: `&'a (dyn Dummy + 'a)` cannot be sent between threads safely --> $DIR/kindck-send-object1.rs:10:19 | LL | assert_send::<&'a dyn Dummy>(); | ^^^^^^^^^^^^^ `&'a (dyn Dummy + 'a)` cannot be sent between threads safely | = help: the trait `Sync` is not implemented for `(dyn Dummy + 'a)`, which is required by `&'a (dyn Dummy + 'a): Send` = note: required for `&'a (dyn Dummy + 'a)` to implement `Send` note: required by a bound in `assert_send` --> $DIR/kindck-send-object1.rs:5:18 | LL | fn assert_send() { } | ^^^^ required by this bound in `assert_send` error[E0277]: `(dyn Dummy + 'a)` cannot be sent between threads safely --> $DIR/kindck-send-object1.rs:29:19 | LL | assert_send::>(); | ^^^^^^^^^^^^^^^^^^^ `(dyn Dummy + 'a)` cannot be sent between threads safely | = help: the trait `Send` is not implemented for `(dyn Dummy + 'a)`, which is required by `Box<(dyn Dummy + 'a)>: Send` = note: required for `Unique<(dyn Dummy + 'a)>` to implement `Send` note: required because it appears within the type `Box<(dyn Dummy + 'a)>` --> $SRC_DIR/alloc/src/boxed.rs:LL:COL note: required by a bound in `assert_send` --> $DIR/kindck-send-object1.rs:5:18 | LL | fn assert_send() { } | ^^^^ required by this bound in `assert_send` error: lifetime may not live long enough --> $DIR/kindck-send-object1.rs:14:5 | LL | fn test52<'a>() { | -- lifetime `'a` defined here LL | assert_send::<&'a (dyn Dummy + Sync)>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static` error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0277`.