terraform variable usage - strange way to reference a variable - amazon-web-services

Question

I stuck at old code written by another developer 2 years before, that I can't pass the terraform validate. I tried validate with old terrafrom version as well, 0.11, 0.13, 0.15 and 1.0
variable "aws_name" {
default = "${aws:name}"
}
I am confused by the sytax, that looks the author try to reference variable from another variable in terraform, but I don't think terraform supports this feature, from beginning.
I mean no support by this way from old versions, such as terrafrom 0.6, to current version 1.0.x
If the code use ${var.xxxx}, I think it was the code created before terraform 0.12, because after that, we don't need "${ }" to reference a variable, we can directly reference it via var.aws_name
Second we can't reference a variable as "aws:name" without "var" in front of it, and colon will misleading in terraform as well.
Any one knew this way in terraform, is it validated in some of terrafrom versions?
Update
As #Matt Schuchard mentioned, the azure pipeline task replacetokens#4 does support other style for the replacement (the fourth)

Answer 1

try to reference variable from another variable in terraform, but I don't think terraform supports this feature
That's correct. You can't do this. The only reason for that I can think of is that the terraform was part of some CI/CD pipeline. Thus, maybe before the actual TF scripts were run, they were per-processed by an external tool, which made simple find-and-replace of ${aws:name} string to valid values.
One possibility could be Before Hooks in terragrunt.