Restructure early break in recreate_vacant_list() (#132)

Author: CosmicHorrorDev

src/lib.rs

@@ -442,17 +442,21 @@ impl<T> Slab<T> {
         self.next = self.entries.len();
         // We can stop once we've found all vacant entries
         let mut remaining_vacant = self.entries.len() - self.len;
+        if remaining_vacant == 0 {
+            return;
+        }
+
         // Iterate in reverse order so that lower keys are at the start of
         // the vacant list. This way future shrinks are more likely to be
         // able to remove vacant entries.
         for (i, entry) in self.entries.iter_mut().enumerate().rev() {
-            if remaining_vacant == 0 {
-                break;
-            }
             if let Entry::Vacant(ref mut next) = *entry {
                 *next = self.next;
                 self.next = i;
                 remaining_vacant -= 1;
+                if remaining_vacant == 0 {
+                    break;
+                }
             }
         }
     }