implement zeroed and uninitialized with MaybeUninit

src/test/ui/init-large-type.rs

@@ -10,17 +10,13 @@
 
 #![feature(intrinsics)]
 
-use std::thread;
-
-extern "rust-intrinsic" {
-    pub fn init<T>() -> T;
-}
+use std::{mem, thread};
 
 const SIZE: usize = 1024 * 1024;
 
 fn main() {
     // do the test in a new thread to avoid (spurious?) stack overflows
     thread::spawn(|| {
-        let _memory: [u8; SIZE] = unsafe { init() };
+        let _memory: [u8; SIZE] = unsafe { mem::zeroed() };
     }).join();
 }

src/test/ui/init-unsafe.rs

@@ -1,9 +0,0 @@
-#![allow(deprecated)]
-#![feature(core_intrinsics)]
-
-use std::intrinsics::{init};
-
-// Test that the `init` intrinsic is really unsafe
-pub fn main() {
-    let stuff = init::<isize>(); //~ ERROR call to unsafe function is unsafe
-}

src/test/ui/init-unsafe.stderr

@@ -1,11 +0,0 @@
-error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
-  --> $DIR/init-unsafe.rs:8:17
-   |
-LL |     let stuff = init::<isize>();
-   |                 ^^^^^^^^^^^^^^^ call to unsafe function
-   |
-   = note: consult the function's documentation for information on how to avoid undefined behavior
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0133`.

src/test/ui/intrinsics/intrinsic-move-val.rs

@@ -5,7 +5,6 @@
 
 mod rusti {
     extern "rust-intrinsic" {
-        pub fn init<T>() -> T;
         pub fn move_val_init<T>(dst: *mut T, src: T);
     }
 }
@@ -15,17 +14,17 @@ pub fn main() {
         // sanity check
         check_drops_state(0, None);
 
-        let mut x: Box<D> = box D(1);
-        assert_eq!(x.0, 1);
+        let mut x: Option<Box<D>> = Some(box D(1));
+        assert_eq!(x.as_ref().unwrap().0, 1);
 
         // A normal overwrite, to demonstrate `check_drops_state`.
-        x = box D(2);
+        x = Some(box D(2));
 
         // At this point, one destructor has run, because the
         // overwrite of `x` drops its initial value.
         check_drops_state(1, Some(1));
 
-        let mut y: Box<D> = rusti::init();
+        let mut y: Option<Box<D>> = std::mem::zeroed();
 
         // An initial binding does not overwrite anything.
         check_drops_state(1, Some(1));
@@ -51,9 +50,9 @@ pub fn main() {
         // during such a destructor call. We do so after the end of
         // this scope.
 
-        assert_eq!(y.0, 2);
-        y.0 = 3;
-        assert_eq!(y.0, 3);
+        assert_eq!(y.as_ref().unwrap().0, 2);
+        y.as_mut().unwrap().0 = 3;
+        assert_eq!(y.as_ref().unwrap().0, 3);
 
         check_drops_state(1, Some(1));
     }

src/test/ui/intrinsics/intrinsic-uninit.rs

@@ -1,13 +0,0 @@
-// run-pass
-// pretty-expanded FIXME #23616
-
-#![feature(intrinsics)]
-
-mod rusti {
-    extern "rust-intrinsic" {
-        pub fn uninit<T>() -> T;
-    }
-}
-pub fn main() {
-    let _a : isize = unsafe {rusti::uninit()};
-}