error[E0277]: `*mut &'a isize` cannot be sent between threads safely
  --> $DIR/kindck-send-unsafe.rs:6:19
   |
LL | fn assert_send<T:Send>() { }
   |    -----------   ---- required by this bound in `assert_send`
...
LL |     assert_send::<*mut &'a isize>();
   |                   ^^^^^^^^^^^^^^ `*mut &'a isize` cannot be sent between threads safely
   |
   = help: the trait `std::marker::Send` is not implemented for `*mut &'a isize`

error: aborting due to previous error

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