I am getting Error in terraform execution with “Can’t access attributes on a primitive-typed value (number).”

Here are the details .

Getting Error on ebs_block_mapping variables , I have requirement to add the ebs volumes with different size & type so i have included with mappings .

However ebs_block_mapping variable doesn’t get substituted properly.

main.tf

### EC2 Instance creation
resource "aws_instance" "instance" {
  ami                    = var.ami_id
  subnet_id              = var.subnet_id
  instance_type          = var.instance_type
  key_name               = var.key_pair
  iam_instance_profile   = var.iam_instance_profile
  vpc_security_group_ids = var.security_group_id
  root_block_device {
    volume_type           = var.root_volume_type
    volume_size           = var.root_volume_size
    delete_on_termination = var.delete_on_termination
    encrypted             = "true"
    tags = {
      "Name" = "${var.instance_name}-root"
    }
  }
  dynamic "ebs_block_device" {
    for_each = [for s in var.ebs_device_mappings != null ? [0] : [] : {
      name = s.name
      size = s.size
      type = s.type
    }]
    content {
      device_name           = ebs_block_device.value["name"]
      volume_size           = ebs_block_device.value["size"]
      volume_type           = ebs_block_device.value["type"]
      delete_on_termination = true
      encrypted             = true
      tags = {
        "Name" = "${var.instance_name}-ebs"
      }
    }
  }
}

test.tfvars

instance_type         = "t2.xlarge"
ami_id                = "ami-05de6de"
ebs_device_mappings   = [{ name = "/dev/sdd", size = 50, type = "gp3" }]
security_group_id     = ["sg-xxxxxxxxxxx"]
root_volume_type      = "gp3"
root_volume_size      = "60"
delete_on_termination = "true"
subnet_id             = "subnet-xxxxxxxxxxxx"
iam_instance_profile  = "test-role"
instance_name         = "test"

variables.tf

variable "instance_name" {
  description = "Name tag for EC2 instance"
}
variable "ami_id" {
  description = "AMI ID for EC2 instance"
}
variable "subnet_id" {
  description = "Subnet ID for EC2 instance"
}
variable "instance_type" {
  description = "Instance type for EC2 instance"
}
variable "key_pair" {
  description = "Key pair name for EC2 instance"
  default     = null
}
variable "iam_instance_profile" {
  description = "IAM Instance Profile to launch the instance with"
}
variable "security_group_id" {
  description = "Security group ID for EC2"
}
variable "root_volume_type" {
  description = "EBS root volume type"
}
variable "root_volume_size" {
  description = "EBS root volume size"
}
variable "delete_on_termination" {
  description = "EBS volume deletion on EC2 termination"
}
variable "ebs_device_mappings" {
  default     = null
  description = "Need to provide the device name,volume size and volume type"
}