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// run-pass
#![feature(unboxed_closures, fn_traits)]
struct S;
impl FnMut<(i32,)> for S {
extern "rust-call" fn call_mut(&mut self, (x,): (i32,)) -> i32 {
x * x
}
}
impl FnOnce<(i32,)> for S {
type Output = i32;
extern "rust-call" fn call_once(mut self, args: (i32,)) -> i32 { self.call_mut(args) }
}
fn call_it<F:FnMut(i32)->i32>(mut f: F, x: i32) -> i32 {
f(x) + 3
}
fn call_box(f: &mut dyn FnMut(i32) -> i32, x: i32) -> i32 {
f(x) + 3
}
fn main() {
let x = call_it(S, 1);
let y = call_box(&mut S, 1);
assert_eq!(x, 4);
assert_eq!(y, 4);
}
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