optimize(value): less clone

src/stack.rs

@@ -51,20 +51,12 @@ impl<T, const CAP: usize> Stack<T, CAP> {
         unsafe { replace(item, MaybeUninit::uninit()).assume_init() }
     }
 
-    pub fn tos(&self) -> Result<&T> {
-        if self.top == 0 {
-            panic!("stack empty")
-        } else {
-            Ok(into!(&self.items[self.top - 1]))
-        }
+    pub fn tos(&self) -> &T {
+        into!(&self.items[self.top - 1])
     }
 
-    pub fn tos_mut(&mut self) -> Result<&mut T> {
-        if self.top == 0 {
-            panic!("stack empty")
-        } else {
-            Ok(into!(&mut self.items[self.top - 1]))
-        }
+    pub fn tos_mut(&mut self) -> &mut T {
+        into!(&mut self.items[self.top - 1])
     }
 }