I'm not sure what the issue is here, but consider this example: Module `example`: ```hcl variable "example" { type = map( object({ nested_a = object({ nested_b = list( object({ problem_variable = any }) ) }) }) ) default = {} } resource "null_resource" "example" { for_each = var.example } ``` Note the `any`. Now, assume this top-level module: ``` variable "example" { type = map( object({ name = string nested_a = object({ nested_b = list( object({ problem_variable = any }) ) }) }) ) } module "example" { source = "./example" example = var.example } ``` Now we define a variable `example`, and run `plan`: ```hcl example = { "example a" = { nested_a = { nested_b = [ { problem_variable = {foo = "bar"} } ] } } } ``` ```bash Terraform will perform the following actions: # module.example.null_resource.example["example a"] will be created + resource "null_resource" "example" { + id = (known after apply) } Plan: 1 to add, 0 to change, 0 to destroy. ``` Works fine. Now I add a second entry to the map: ``` "example b" = { name = "foo" nested_a = { nested_b = [ { problem_variable = { foo = "baz" } } ] } } ``` This too works fine: ``` Terraform will perform the following actions: # module.example.null_resource.example["example a"] will be created + resource "null_resource" "example" { + id = (known after apply) } # module.example.null_resource.example["example b"] will be created + resource "null_resource" "example" { + id = (known after apply) } ``` But now let's say I have an entry, `example_c`, where there is no list of values: ``` "example c" = { nested_a = { nested_b = [] # EMPTY. } } ``` I now get this error: ``` Error: Invalid value for module argument on main.tf line 17, in module "example": 17: example = var.example The given value is not suitable for child module variable "example" defined at example/main.tf:1,1-19: object is required. ``` So it appears it wants at least one object in the list (that matches the type of the other objects, of course). Is this by design? Seems wrong ...