diff --git a/semaphore/semaphore_test.go b/semaphore/semaphore_test.go
index ad35dc2..867f71a 100644
--- a/semaphore/semaphore_test.go
+++ b/semaphore/semaphore_test.go
@@ -33,6 +33,7 @@
 	var wg sync.WaitGroup
 	wg.Add(n)
 	for i := 0; i < n; i++ {
+		i := i
 		go func() {
 			defer wg.Done()
 			HammerWeighted(sem, int64(i), 1000)