#![feature(
no_core, lang_items, intrinsics, unboxed_closures, type_ascription, extern_types,
untagged_unions, decl_macro, rustc_attrs, transparent_unions, optin_builtin_traits,
- thread_local, track_caller
+ thread_local,
)]
#![no_core]
#![allow(dead_code)]
#[lang = "fn_once"]
#[rustc_paren_sugar]
pub trait FnOnce<Args> {
+ #[lang = "fn_once_output"]
type Output;
extern "rust-call" fn call_once(self, args: Args) -> Self::Output;