W2001: Parameter <name> not used inaccurate when used in Metadata

[gbudge]

CloudFormation Lint Version

cfn-lint 1.22.0

What operating system are you using?

Windows 10

Describe the bug

When using a template parameter in Metadata, cfn-lint incorrectly raises W2001 that the parameter is not used.

Expected behavior

cfn-lint should not raise W2001 when a parameter is used in Metadata.

Reproduction template

Description: CloudFormation template

Metadata:
  ExampleMetadata: !Sub BucketPurpose

Parameters:
  BucketName:
    Type: String
    Description: Example parameter
  BucketPurpose:
    Type: String
    Description: Example parameter

Resources:
  ExampleResource:
    Type: 'AWS::S3::Bucket'
    Properties:
      BucketName: !Ref BucketName

[kddejong]

I'm trying to find a way to validate this but template metadata section goes unresolved. How are you validating this Sub/Ref function actually does what you want?