1error[E0277]: `F` cannot be sent between threads safely
2  --> $DIR/closure-bounds-cant-promote-superkind-in-struct.rs:5:22
3   |
4LL | fn foo<F>(blk: F) -> X<F> where F: FnOnce() + 'static {
5   |                      ^^^^ `F` cannot be sent between threads safely
6   |
7note: required by a bound in `X`
8  --> $DIR/closure-bounds-cant-promote-superkind-in-struct.rs:1:43
9   |
10LL | struct X<F> where F: FnOnce() + 'static + Send {
11   |                                           ^^^^ required by this bound in `X`
12help: consider further restricting this bound
13   |
14LL | fn foo<F>(blk: F) -> X<F> where F: FnOnce() + 'static + std::marker::Send {
15   |                                                       +++++++++++++++++++
16
17error: aborting due to previous error
18
19For more information about this error, try `rustc --explain E0277`.
20