// vtest build: !sanitize-address-gcc && !sanitize-address-clang
// vtest vflags: -autofree -gc none
// Regression test for the `-autofree` double-free of the `error_sentinel` singleton
// (review on https://github.com/vlang/v/pull/27544). Under `-autofree`, const cleanup
// frees every `IError` const's boxed object; the sentinel can also be copied/re-exported,
// so its shared `MessageError` object must be exempted from `free()` like `none__`.
// `-gc none` is required so `free()` actually returns memory (a double free would abort
// at program cleanup) instead of being a GC no-op.

const my_err = error_sentinel // re-export: shares the same boxed object

fn find(x int) !int {
    if x < 0 {
        return error_sentinel
    }
    return x
}

fn alias_find(x int) !int {
    if x < 0 {
        return my_err
    }
    return x
}

fn test_error_sentinel_autofree_no_double_free() {
    mut misses := 0
    for i := -50; i < 50; i++ {
        find(i) or { misses++ }
        alias_find(i) or { misses++ }
    }
    assert misses == 100
    assert my_err.msg() == 'error'
    assert error_sentinel.msg() == 'error'
}