After raising this [issue](https://github.com/hashicorp/terraform/issues/23231) I started to replace all my empty tuples with `toset([])`. While doing that I found out that there was a configuration in my code where an empty tuple doesn't throw an error. That's the code: ```hcl resource "random_string" "random" { for_each = var.test != null ? var.test : [] length = 16 } variable "test" { type = set(string) default = null } ``` The strange thing is that I got a configuration which is almost the same but throws the right error. The setup is something like that: ```hcl resource "random_string" "random" { for_each = var.test != null ? var.test.list : [] length = 16 } variable "test" { type = object({ list = set(string) string = string }) default = null } ``` In both cases I don't pass in any value for the test variable, `var.test` will be null and the for_each should get an empty tuple from the condition. ### Terraform Version <!--- Run `terraform -v` to show the version, and paste the result between the ``` marks below. If you are not running the latest version of Terraform, please try upgrading because your issue may have already been fixed. --> ``` Terraform v0.12.13 + provider.random v2.2.1 ``` ### Terraform Configuration Files <!-- Paste the relevant parts of your Terraform configuration between the ``` marks below. For large Terraform configs, please use a service like Dropbox and share a link to the ZIP file. For security, you can also encrypt the files using our GPG public key. --> ```hcl resource "random_string" "random" { for_each = var.test != null ? var.test : [] length = 16 } variable "test" { type = set(string) default = null } ``` ### Expected Behavior <!-- What should have happened? --> Terraform should throw an error because of the empty tuple. ### Actual Behavior <!-- What actually happened? --> The code is running without any problems. ### Steps to Reproduce <!-- Please list the full steps required to reproduce the issue, for example: 1. `terraform init` 2. `terraform apply` --> 1. `terraform init` 2. `terraform apply`