diff --git a/func_test.go b/func_test.go
index 8f3b81a..b56291e 100644
--- a/func_test.go
+++ b/func_test.go
@@ -26,7 +26,7 @@
 		},
 	}
 	ev := NewEvaluator(make(map[string]Var))
-	var buf buffer
+	var buf evalBuffer
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -45,7 +45,7 @@
 		},
 	}
 	ev := NewEvaluator(make(map[string]Var))
-	var buf buffer
+	var buf evalBuffer
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -66,7 +66,7 @@
 		},
 	}
 	ev := NewEvaluator(make(map[string]Var))
-	var buf buffer
+	var buf evalBuffer
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {