diff --git a/azurestack/resource_arm_route_table.go b/azurestack/resource_arm_route_table.go
index 1a7e399fe..7d553841a 100644
--- a/azurestack/resource_arm_route_table.go
+++ b/azurestack/resource_arm_route_table.go
@@ -249,10 +249,10 @@ func flattenRouteTableRoutes(input *[]network.Route) []interface{} {
 	return results
 }
 
-func flattenRouteTableSubnets(input *[]network.Subnet) []string {
+func flattenRouteTableSubnets(subnets *[]network.Subnet) []string {
 	output := []string{}
 
-	if subnets := input; subnets != nil {
+	if subnets != nil {
 		for _, subnet := range *subnets {
 			output = append(output, *subnet.ID)
 		}