examples, tests: prepare to enable clippy::undocumented_unsafe_blocks lint

Signed-off-by: Paolo Bonzini <[email protected]>

Author: bonzini

examples/linked_list.rs

@@ -1,3 +1,4 @@
+#![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 
 use core::{

examples/mutex.rs

@@ -1,3 +1,4 @@
+#![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 
 use core::{

examples/pthread_mutex.rs

@@ -1,4 +1,5 @@
 // inspired by https://github.com/nbdd0121/pin-init/blob/trunk/examples/pthread_mutex.rs
+#![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 #[cfg(not(windows))]
 mod pthread_mtx {

examples/static_init.rs

@@ -1,3 +1,4 @@
+#![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 
 use core::{

tests/many_generics.rs

@@ -22,6 +22,7 @@ where
     T: Bar<'b, 1>,
 {
     fn drop(self: Pin<&mut Self>) {
+        // SAFETY: we do not move out of `self`
         let me = unsafe { Pin::get_unchecked_mut(self) };
         for t in &mut *me.r {
             Bar::<'a, 1>::bar(*t);

tests/ring_buf.rs

@@ -1,3 +1,4 @@
+#![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 
 use core::{

tests/zeroing.rs

@@ -19,7 +19,8 @@ impl Foo {
         pin_init!(&this in Self {
             marks: {
                 let ptr = this.as_ptr();
-                let ptr = unsafe { addr_of_mut!((*ptr).buf)}.cast::<u8>();
+                // SAFETY: project from the NonNull<Foo> to the buf field
+                let ptr = unsafe { addr_of_mut!((*ptr).buf) }.cast::<u8>();
                 [ptr; MARKS]},
             ..Zeroable::zeroed()
         })