Creating and attaching an inline policy to a group

Hi,

I can manually create and attach an inline policy to a group in AWS console. However, I cannot find an example to do this with Terrafom files. My attempts create normal policies under the group rather than an inline one. Definitely missing something or doing something wrong.

Thanks

resource "aws_iam_group" "devops" {
  name = "devops"
}

resource "aws_iam_policy" "terraform_access" {
  name = "terraform-access"

  policy = jsonencode(
    {
      "Version" : "2012-10-17",
      "Statement" : [
        {
          "Effect" : "Allow",
          "Action" : "*",
          "Resource" : "*"
        }
      ]
    }
  )
}

resource "aws_iam_role" "terraform" {
  name = "terraform"

  assume_role_policy = jsonencode(
    {
      "Version" : "2012-10-17",
      "Statement" : [
        {
          "Effect" : "Allow",
          "Action" : "sts:AssumeRole",
          "Principal" : {
            "AWS" : "arn:aws:iam::0123456789:root"
          }
        }
      ]
    }
  )
}

# THIS WAS MEANT TO BE THE INLINE POLICY!
resource "aws_iam_policy" "assume_terraform_role" {
  name = "assume-terraform-role"

  policy = jsonencode(
    {
      "Version" : "2012-10-17",
      "Statement" : [
        {
          "Effect" : "Allow",
          "Action" : "sts:AssumeRole",
          "Resource" : "arn:aws:iam::0123456789:role/terraform"
        }
      ]
    }
  )
}

resource "aws_iam_group_policy_attachment" "devops_assume_terraform_role" {
  group      = aws_iam_group.devops.name
  policy_arn = aws_iam_policy.assume_terraform_role.arn
}

I managed to solve by relying on Customer managed policy so this is not an issue anymore, please disregard.