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// General test of maybe_uninits state computed by MIR dataflow.
#![feature(core_intrinsics, rustc_attrs)]
use std::intrinsics::rustc_peek;
use std::mem::{drop, replace};
struct S(i32);
#[rustc_mir(rustc_peek_maybe_uninit,stop_after_dataflow)]
fn foo(test: bool, x: &mut S, y: S, mut z: S) -> S {
let ret;
// `ret` starts off uninitialized
rustc_peek(&ret);
// All function formal parameters start off initialized.
rustc_peek(&x); //~ ERROR rustc_peek: bit not set
rustc_peek(&y); //~ ERROR rustc_peek: bit not set
rustc_peek(&z); //~ ERROR rustc_peek: bit not set
ret = if test {
::std::mem::replace(x, y)
} else {
z = y;
z
};
// `z` may be uninitialized here.
rustc_peek(&z);
// `y` is definitely uninitialized here.
rustc_peek(&y);
// `x` is still (definitely) initialized (replace above is a reborrow).
rustc_peek(&x); //~ ERROR rustc_peek: bit not set
::std::mem::drop(x);
// `x` is *definitely* uninitialized here
rustc_peek(&x);
// `ret` is now definitely initialized (via `if` above).
rustc_peek(&ret); //~ ERROR rustc_peek: bit not set
ret
}
fn main() {
foo(true, &mut S(13), S(14), S(15));
foo(false, &mut S(13), S(14), S(15));
}
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