Local variable not inferred causing failures

[t-botz]

• terrascan version: v1.12.0
• Operating System: Mac and Linux

Description

When using a local variable instead of hardcoded value, I get an error. Minimal example

locals {
  engine      = "redis"
}

resource "aws_elasticache_cluster" "redis" {
  engine       = local.engine.    # Cause error "ElastiCache for Memcached is not in use in AWS PCI DSS environments"
  cluster_id  = "aa"
}

The following code doesnt code any error:

resource "aws_elasticache_cluster" "redis" {
  engine       = "redis"
  cluster_id  = "aa"
}

What I Did

$ terrascan scan -f test.tf


Violation Details -
    
        Description    :        ElastiCache for Memcached is not in use in AWS PCI DSS environments
        File           :        test.tf
        Module Name    :        root
        Line           :        6
        Severity       :        HIGH
        -----------------------------------------------------------------------
        

Scan Summary -

        File/Folder         :   /Users/thibault.delor/workspace/graphql-gateway/terraform/environments/modules/redis/test.tf
        IaC Type            :   terraform
        Scanned At          :   2021-12-21 01:07:28.168827 +0000 UTC
        Policies Validated  :   3
        Violated Policies   :   1
        Low                 :   0
        Medium              :   0
        High                :   1

On my CI/CD, I use github super linter (which always lint file by file)