| // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // General test of maybe_uninits state computed by MIR dataflow. |
| |
| #![feature(nll)] |
| #![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 |
| unsafe { rustc_peek(&ret); } |
| |
| // All function formal parameters start off initialized. |
| |
| unsafe { rustc_peek(&x) }; //~ ERROR rustc_peek: bit not set |
| unsafe { rustc_peek(&y) }; //~ ERROR rustc_peek: bit not set |
| unsafe { 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. |
| unsafe { rustc_peek(&z); } |
| |
| // `y` is definitely uninitialized here. |
| unsafe { rustc_peek(&y); } |
| |
| // `x` is still (definitely) initialized (replace above is a reborrow). |
| unsafe { rustc_peek(&x); } //~ ERROR rustc_peek: bit not set |
| |
| ::std::mem::drop(x); |
| |
| // `x` is *definitely* uninitialized here |
| unsafe { rustc_peek(&x); } |
| |
| // `ret` is now definitely initialized (via `if` above). |
| unsafe { 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)); |
| } |