error[E0277]: `F` cannot be shared between threads safely
  --> $DIR/closure-bounds-subtype.rs:13:22
   |
LL |     take_const_owned(f);
   |     ---------------- ^ `F` cannot be shared between threads safely
   |     |
   |     required by a bound introduced by this call
   |
note: required by a bound in `take_const_owned`
  --> $DIR/closure-bounds-subtype.rs:4:50
   |
LL | fn take_const_owned<F>(_: F) where F: FnOnce() + Sync + Send {
   |                                                  ^^^^ required by this bound in `take_const_owned`
help: use parentheses to call this type parameter
   |
LL |     take_const_owned(f());
   |                       ++
help: consider further restricting this bound
   |
LL | fn give_owned<F>(f: F) where F: FnOnce() + Send + std::marker::Sync {
   |                                                 +++++++++++++++++++

error: aborting due to previous error

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