fn help(f: fn(a: &int, b: &int) -> int) {} // OK
fn help2<F: Fn(&int, &int) -> int>(f: F) {} // error
->
hhh.rs:3:16: 3:20 error: missing lifetime specifier [E0106]
hhh.rs:3 fn help2<F: Fn(&int, &int) -> int>(f: F) {}
^~~~
hhh.rs:3:22: 3:26 error: missing lifetime specifier [E0106]
hhh.rs:3 fn help2<F: Fn(&int, &int) -> int>(f: F) {}
^~~~
It seems like it can't possibly be right that this would work for one but not the other.