unstably constify ptr::drop_in_place

Author: Qelxiros

library/core/src/ptr/mod.rs

@@ -801,7 +801,8 @@ pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
 #[lang = "drop_in_place"]
 #[allow(unconditional_recursion)]
 #[rustc_diagnostic_item = "ptr_drop_in_place"]
-pub unsafe fn drop_in_place<T: PointeeSized>(to_drop: *mut T) {
+#[rustc_const_unstable(feature = "const_drop_in_place", issue = "109342")]
+pub const unsafe fn drop_in_place<T: PointeeSized>(to_drop: *mut T) {
     // Code here does not matter - this is replaced by the
     // real drop glue by the compiler.