1 // error-pattern: requires `generator` lang_item
2 #![feature(no_core, lang_items, unboxed_closures)]
5 #[lang = "sized"] pub trait Sized { }
9 pub trait FnOnce<Args> {
12 extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
15 pub fn abc() -> impl FnOnce(f32) {