Validation of IAM ARNs

[volphy]

Would it be possible to add validation of IAM ARNs?

For example the following ARN is incorrect and leads to issues that are reported only by AWS Management Console's IAM Role JSON edit mode:
'arn:aws:logs::eu-west-1::log-group:/aws/vpc/flowlogs/'

Correct IAM Role ARN:
'arn:aws:logs:eu-west-1::log-group:/aws/vpc/flowlogs/'

This validation would be really useful if it could be applied not only to statically hard-coded ARNs but to dynamically created (Fn::Join) ARNs as well.