1 struct X<F> where F: FnOnce() + 'static + Send {
2     field: F,
3 }
4 
foo<F>(blk: F) -> X<F> where F: FnOnce() + 'static5 fn foo<F>(blk: F) -> X<F> where F: FnOnce() + 'static {
6     //~^ ERROR `F` cannot be sent between threads safely
7     return X { field: blk };
8 }
9 
main()10 fn main() {
11 }
12