diff --git a/common/common.go b/common/common.go
index 47d47dbde..36b654900 100644
--- a/common/common.go
+++ b/common/common.go
@@ -11,6 +11,7 @@ func Must(err error) {
 	}
 }
 
+// Must2 panics if the second parameter is not nil.
 func Must2(v interface{}, err error) {
 	if err != nil {
 		panic(err)