| // error-pattern: requires `generator` lang_item | |
| #![feature(no_core, lang_items, unboxed_closures)] | |
| #![no_core] | |
| #[lang = "sized"] pub trait Sized { } | |
| #[lang = "fn_once"] | |
| #[rustc_paren_sugar] | |
| pub trait FnOnce<Args> { | |
| type Output; | |
| extern "rust-call" fn call_once(self, args: Args) -> Self::Output; | |
| } | |
| pub fn abc() -> impl FnOnce(f32) { | |
| |_| {} | |
| } | |
| fn main() {} |