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//@ run-pass
#![feature(test)]
#![allow(unused_mut)] // under NLL we get warning about `x` below: rust-lang/rust#54499
// This test is bogus (i.e., should be check-fail) during the period
// where #54986 is implemented and #54987 is *not* implemented. For
// now: just ignore it
//
//@ ignore-test (#54987)
// This test is checking that the space allocated for `x.1` does not
// overlap with `y`. (The reason why such a thing happened at one
// point was because `x.0: Void` and thus the whole type of `x` was
// uninhabited, and so the compiler thought it was safe to use the
// space of `x.1` to hold `y`.)
//
// That's a fine thing to test when this code is accepted by the
// compiler, and this code is being transcribed accordingly into
// the ui test issue-21232-partial-init-and-use.rs
extern crate test;
enum Void {}
fn main() {
let mut x: (Void, usize);
let mut y = 42;
x.1 = 13;
// Make sure `y` stays on the stack.
test::black_box(&mut y);
// Check that the write to `x.1` did not overwrite `y`.
// Note that this doesn't fail with optimizations enabled,
// because we can't keep `x.1` on the stack, like we can `y`,
// as we can't borrow partially initialized variables.
assert_eq!(y.to_string(), "42");
// Check that `(Void, usize)` has space for the `usize` field.
assert_eq!(std::mem::size_of::<(Void, usize)>(),
std::mem::size_of::<usize>());
}
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