Add From impls for wrapper types

- `From<T> for ThinBox<T>`
- `From<T> for UniqueRc<T>`
- `From<T> for UniqueArc<T>`
- `From<T> for ManuallyDrop<T>`
- `From<T> for AssertUnwindSafe<T>`

Author: Jules-Bertholet

library/alloc/src/boxed/thin.rs

@@ -430,3 +430,11 @@ impl<T: ?Sized + Error> Error for ThinBox<T> {
         self.deref().source()
     }
 }
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T> From<T> for ThinBox<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}

library/alloc/src/rc.rs

@@ -3816,6 +3816,14 @@ impl<T: ?Sized, A: Allocator> AsMut<T> for UniqueRc<T, A> {
 #[unstable(feature = "unique_rc_arc", issue = "112566")]
 impl<T: ?Sized, A: Allocator> Unpin for UniqueRc<T, A> {}
 
+#[unstable(feature = "unique_rc_arc", issue = "112566")]
+impl<T> From<T> for UniqueRc<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}
+
 #[unstable(feature = "unique_rc_arc", issue = "112566")]
 impl<T: ?Sized + PartialEq, A: Allocator> PartialEq for UniqueRc<T, A> {
     /// Equality for two `UniqueRc`s.

library/alloc/src/sync.rs

@@ -4242,6 +4242,14 @@ impl<T: ?Sized, A: Allocator> AsMut<T> for UniqueArc<T, A> {
     }
 }
 
+#[unstable(feature = "unique_rc_arc", issue = "112566")]
+impl<T> From<T> for UniqueArc<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}
+
 #[unstable(feature = "unique_rc_arc", issue = "112566")]
 impl<T: ?Sized, A: Allocator> Unpin for UniqueArc<T, A> {}
 

library/core/src/mem/manually_drop.rs

@@ -276,3 +276,11 @@ impl<T: ?Sized> DerefMut for ManuallyDrop<T> {
 
 #[unstable(feature = "deref_pure_trait", issue = "87121")]
 unsafe impl<T: ?Sized> DerefPure for ManuallyDrop<T> {}
+
+#[stable(feature = "from_wrapper_impls", since = "CURRENT_RUSTC_VERSION")]
+impl<T> From<T> for ManuallyDrop<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self::new(value)
+    }
+}

library/core/src/panic/unwind_safe.rs

@@ -311,3 +311,11 @@ impl<S: AsyncIterator> AsyncIterator for AssertUnwindSafe<S> {
         self.0.size_hint()
     }
 }
+
+#[stable(feature = "from_wrapper_impls", since = "CURRENT_RUSTC_VERSION")]
+impl<T> From<T> for AssertUnwindSafe<T> {
+    #[inline(always)]
+    fn from(value: T) -> Self {
+        Self(value)
+    }
+}