turn `ManuallyDrop::new` into a constant function

diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs
index e3f08926610f69592ecb583a7165b05d5fc0ddad..6d64d91312e0f525a89e2957a2eb48a69812c301 100644 (file)
--- a/src/libcore/mem.rs
+++ b/src/libcore/mem.rs
@@ -960,7 +960,7 @@ impl<T> ManuallyDrop<T> {
     /// ```
     #[stable(feature = "manually_drop", since = "1.20.0")]
     #[inline]
-    pub fn new(value: T) -> ManuallyDrop<T> {
+    pub const fn new(value: T) -> ManuallyDrop<T> {
         ManuallyDrop { value: value }
     }