Fixes #83

viper.go

diff --git a/viper.go b/viper.go
index 3db9cd2..f2c09ce 100644
--- a/viper.go
+++ b/viper.go
@@ -522,11 +522,11 @@
 
 	switch flag.Value.Type() {
 	case "int", "int8", "int16", "int32", "int64":
-		SetDefault(key, cast.ToInt(flag.Value.String()))
+		v.SetDefault(key, cast.ToInt(flag.Value.String()))
 	case "bool":
-		SetDefault(key, cast.ToBool(flag.Value.String()))
+		v.SetDefault(key, cast.ToBool(flag.Value.String()))
 	default:
-		SetDefault(key, flag.Value.String())
+		v.SetDefault(key, flag.Value.String())
 	}
 	return nil
 }