switch to go way of checking for key existence so that go doesn't crash when the value doesn't exist

builtin/providers/aws/resource_aws_nat_gateway.go

@@ -108,7 +108,7 @@ func resourceAwsNatGatewayRead(d *schema.ResourceData, meta interface{}) error {
 		"failed":   true,
 	}
 
-	if ngRaw == nil || status[strings.ToLower(state)] {
+	if _, ok := status[strings.ToLower(state)]; ngRaw == nil || ok {
 		log.Printf("[INFO] Removing %s from Terraform state as it is not found or in the deleted state.", d.Id())
 		d.SetId("")
 		return nil

builtin/providers/aws/resource_aws_nat_gateway_test.go

@@ -43,13 +43,13 @@ func testAccCheckNatGatewayDestroy(s *terraform.State) error {
 		resp, err := conn.DescribeNatGateways(&ec2.DescribeNatGatewaysInput{
 			NatGatewayIds: []*string{aws.String(rs.Primary.ID)},
 		})
-		status := map[string]bool{
-			"deleted":  false,
-			"deleting": false,
-			"failed":   false,
-		}
 		if err == nil {
-			if len(resp.NatGateways) > 0 && status[strings.ToLower(*resp.NatGateways[0].State)] {
+			status := map[string]bool{
+				"deleted":  true,
+				"deleting": true,
+				"failed":   true,
+			}
+			if _, ok := status[strings.ToLower(*resp.NatGateways[0].State)]; len(resp.NatGateways) > 0 && !ok {
 				return fmt.Errorf("still exists")
 			}