Deprecated interpolation TF-L0037

Terraform v0.12 introduces a new interpolation syntax, but continues to support the old 0.11-style interpolation syntax for compatibility. Terraform will currently print diagnostic warnings when deprecated interpolations are used. Consistent with its deprecation policy, they will raise errors in the next major release (v0.13). It is recommended to switch to the new interpolation syntax.

Example:

resource "aws_instance" "deprecated" {
    instance_type = "${var.type}"
}

resource "aws_instance" "new" {
    instance_type = var.type
}