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//@ normalize-stderr-test: "(\n)ALLOC \(.*\) \{\n(.*\n)*\}(\n)" -> "${1}ALLOC DUMP${3}"
//@ normalize-stderr-test: "\[0x[0-9a-z]..0x[0-9a-z]\]" -> "[0xX..0xY]"
#![feature(core_intrinsics)]
use std::mem::{self, MaybeUninit};
fn main() {
// This constructs a `(usize, bool)` pair: 9 bytes initialized, the rest not.
// Ensure that these 9 bytes are indeed initialized, and the rest is indeed not.
// This should be the case even if we write into previously initialized storage.
let mut x: MaybeUninit<Box<[u8]>> = MaybeUninit::zeroed();
let z = std::intrinsics::add_with_overflow(0usize, 0usize);
unsafe { x.as_mut_ptr().cast::<(usize, bool)>().write(z) };
// Now read this bytewise. There should be (`ptr_size + 1`) def bytes followed by
// (`ptr_size - 1`) undef bytes (the padding after the bool) in there.
let z: *const u8 = &x as *const _ as *const _;
let first_undef = mem::size_of::<usize>() as isize + 1;
for i in 0..first_undef {
let byte = unsafe { *z.offset(i) };
assert_eq!(byte, 0);
}
let v = unsafe { *z.offset(first_undef) };
//~^ ERROR: uninitialized
if v == 0 {
println!("it is zero");
}
}
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