impl CloneToUninit for Path and OsStr

library/std/src/path/tests.rs

@@ -3,6 +3,8 @@ use core::hint::black_box;
 use super::*;
 use crate::collections::{BTreeSet, HashSet};
 use crate::hash::DefaultHasher;
+use crate::mem::MaybeUninit;
+use crate::ptr;
 
 #[allow(unknown_lints, unused_macro_rules)]
 macro_rules! t (
@@ -2054,3 +2056,20 @@ fn bench_hash_path_long(b: &mut test::Bencher) {
 
     black_box(hasher.finish());
 }
+
+#[test]
+fn clone_to_uninit() {
+    let a = Path::new("hello.txt");
+
+    let mut storage = vec![MaybeUninit::<u8>::uninit(); size_of_val::<Path>(a)];
+    unsafe { a.clone_to_uninit(ptr::from_mut::<[_]>(storage.as_mut_slice()) as *mut Path) };
+    assert_eq!(a.as_os_str().as_encoded_bytes(), unsafe {
+        MaybeUninit::slice_assume_init_ref(&storage)
+    });
+
+    let mut b: Box<Path> = Path::new("world.exe").into();
+    assert_eq!(size_of_val::<Path>(a), size_of_val::<Path>(&b));
+    assert_ne!(a, &*b);
+    unsafe { a.clone_to_uninit(ptr::from_mut::<Path>(&mut b)) };
+    assert_eq!(a, &*b);
+}