AtomicCell: Make as_ptr const

Author: taiki-e

crossbeam-utils/Cargo.toml

@@ -47,6 +47,7 @@ loom = { version = "0.7.1", optional = true }
 
 [dev-dependencies]
 fastrand = "2"
+rustversion = "1"
 
 [lints]
 workspace = true

crossbeam-utils/src/atomic/atomic_cell.rs

@@ -181,7 +181,7 @@ impl<T> AtomicCell<T> {
     /// let ptr = a.as_ptr();
     /// ```
     #[inline]
-    pub fn as_ptr(&self) -> *mut T {
+    pub const fn as_ptr(&self) -> *mut T {
         self.value.get().cast::<T>()
     }
 }

crossbeam-utils/tests/atomic_cell.rs

@@ -73,12 +73,6 @@ fn is_lock_free() {
     };
 }
 
-#[test]
-fn const_is_lock_free() {
-    const _U: bool = AtomicCell::<usize>::is_lock_free();
-    const _I: bool = AtomicCell::<isize>::is_lock_free();
-}
-
 #[test]
 fn drops_unit() {
     static CNT: AtomicUsize = AtomicUsize::new(0);
@@ -279,7 +273,15 @@ fn garbage_padding() {
 }
 
 #[test]
-fn const_atomic_cell_new() {
+fn const_atomic_cell() {
+    const _IS_LOCK_FREE_U: bool = AtomicCell::<usize>::is_lock_free();
+    const _IS_LOCK_FREE_I: bool = AtomicCell::<isize>::is_lock_free();
+    #[rustversion::since(1.83)]
+    static _AS_PTR: AtomicCell<usize> = {
+        let v = AtomicCell::new(!0);
+        let _p = v.as_ptr();
+        v
+    };
     static CELL: AtomicCell<usize> = AtomicCell::new(0);
 
     CELL.store(1);