---
AWSTemplateFormatVersion: "2010-09-09"
Mappings:
  CertificateMap:
    us-east-1:
      Arn: arn:aws:acm:us-east-1:<account>:certificate/<id>
    2:
      Arn: "" # Empty string is a valid value
Resources:
  AppAlbListener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      Certificates:
        - CertificateArn:
            Fn::FindInMap: [CertificateMap, !Ref 'AWS::Region', !Ref 'AWS::Region']
            # Doesn't fail when a Ref is used
  AppAlbListener1:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      Certificates:
        - CertificateArn:  # Doesn't fail with hardcoded string
            Fn::FindInMap: [CertificateMap, 'us-east-1', Arn]
  AppAlbListener2:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      Certificates:
        - CertificateArn:  # Doesn't fail with map is dynamic
            Fn::FindInMap: [!Ref 'AWS::Region', 'us-west-2', id]
  AppAlbListener3:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      Certificates:
        - CertificateArn:  # Doesn't fail with integer
            Fn::FindInMap: [!Ref 'AWS::Region', 2, id]