// run-pass #[derive(Debug)] struct MyStruct; trait Repro { fn repro(self, s: MyStruct) -> String; } impl Repro for F where F: FnOnce(MyStruct) -> String { fn repro(self, s: MyStruct) -> String { self(s) } } fn do_stuff(r: R) -> String { r.repro(MyStruct) } pub fn main() { assert_eq!("MyStruct".to_string(), do_stuff(|s: MyStruct| format!("{:?}", s))); }