rust/tests/ui/structs-enums/struct-order-of-eval-3.rs

// run-pass
// Checks that functional-record-update order-of-eval is as expected
// even when no Drop-implementations are involved.

use std::sync::atomic::{Ordering, AtomicUsize};

struct W { wrapped: u32 }
struct S { f0: W, _f1: i32 }

pub fn main() {
    const VAL: u32 = 0x89AB_CDEF;
    let w = W { wrapped: VAL };
    let s = S {
        f0: { event(0x01); W { wrapped: w.wrapped + 1 } },
        ..S {
            f0: { event(0x02); w},
            _f1: 23
        }
    };
    assert_eq!(s.f0.wrapped, VAL + 1);
    let actual = event_log();
    let expect = 0x01_02;
    assert!(expect == actual,
            "expect: 0x{:x} actual: 0x{:x}", expect, actual);
}

static LOG: AtomicUsize = AtomicUsize::new(0);

fn event_log() -> usize {
    LOG.load(Ordering::SeqCst)
}

fn event(tag: u8) {
    let old_log = LOG.load(Ordering::SeqCst);
    let new_log = (old_log << 8) + tag as usize;
    LOG.store(new_log, Ordering::SeqCst);
}