Shared via Rust Playground

playground.rs

#![feature(unboxed_closures)]
#![feature(fn_traits)]

#[derive(Clone)]
struct Foo (i32);

type Bar = i32;

impl Foo {
    fn go(&self, _: &i32) { }
}

fn _ice() {
    let a = vec![].into_iter();
    let _ = a.map(Foo(1).clone());
}


impl FnOnce<(Bar,)> for Foo {
    type Output = ();
    extern "rust-call" fn call_once(self, (args,): (Bar,)) -> Self::Output {
        self.go(&args)
    }
}

impl FnMut<(Bar,)> for Foo {
    extern "rust-call" fn call_mut(&mut self, (args,): (Bar,)) -> Self::Output {
        self.go(&args)
    }
}


impl FnOnce<Bar> for Foo {
    type Output = ();
    extern "rust-call" fn call_once(self, args: Bar) -> Self::Output {
        self.go(&args)
    }
}
impl FnMut<Bar> for Foo {
    extern "rust-call" fn call_mut(&mut self, args: Bar) -> Self::Output {
        self.go(&args)
    }
}



fn main() {


}