Many rules in ACR detect either wrong code, or code that is more likely to result in bugs or other problems.
ACR is a static analysis tool that scans your Mendix model and compares it against a database of rules based on Mendix best practices and other developer guidelines. It then reports when a rule is violated. These violations are grouped into categories that helps you find bugs, code smells, and security vulnerabilities.
Bugs
Violations that fall under the Reliability category often point to buggy code. Buggy code is code that is likely not working as intended. For example, referring to the currentUser in a system process will result in an error during runtime.

Code smells
Smelly code probably does what it should, but it is hard to maintain. As new features are built, smelly code tends to develop into real issues. Violations in the Maintainability category point to different code smells such as large microflows or entities.

Security vulnerabilities
See detailed descriptions of potential security vulnerabilities in your project. By fixing the Security violations you can secure your app and it’s data.
