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// RFC 736 (and Issue 21407): functional struct update should respect privacy.
// The `foo` module attempts to maintains an invariant that each `S`
// has a unique `u64` id.
use self::foo::S;
mod foo {
use std::cell::{UnsafeCell};
static mut COUNT : UnsafeCell<u64> = UnsafeCell::new(1);
pub struct S { pub a: u8, pub b: String, secret_uid: u64 }
pub fn make_secrets(a: u8, b: String) -> S {
let val = unsafe { let p = COUNT.get(); let val = *p; *p = val + 1; val };
println!("creating {}, uid {}", b, val);
S { a: a, b: b, secret_uid: val }
}
impl Drop for S {
fn drop(&mut self) {
println!("dropping {}, uid {}", self.b, self.secret_uid);
}
}
}
fn main() {
let s_1 = foo::make_secrets(3, format!("ess one"));
let s_2 = foo::S { b: format!("ess two"), ..s_1 }; // FRU ...
//~^ ERROR field `secret_uid` of struct `S` is private
println!("main forged an S named: {}", s_2.b);
// at end of scope, ... both s_1 *and* s_2 get dropped. Boom!
}
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