terraform plan throws error "concat: argument 1 should be type list, got type string"

[oveits]

With terraform 0.7.4, the line

Name = "${concat("node", count.index)}"

in ec2/main.tf is causing the following error message:

$ terraform plan
There are warnings and/or errors related to your configuration. Please
fix these before continuing.

Errors:

  * At column 3, line 1: concat: argument 1 should be type list, got type string in:

${concat("node", count.index)}
  * At column 3, line 1: concat: argument 1 should be type list, got type string in:

${concat("node", count.index)}

I have found following closed terraform issue #6792 that is telling us that concat is not supported for strings anymore.

How about changing the line to

Name = "node${count.index}"

?
This yields Names like

    tags.Name:                                 "node0"

and

    tags.Name:                                 "node1"

when running terraform plan.

[oveits]

This issue is now followed up on issue #4 with the corresponding pull request. Therefore, I close this as a duplicate.