Roslyn analyzers that spot Bugs, Vulnerabilities and Code Smells in your code. For an even better overall experience, you can use SonarQube for IDE (Visual Studio, Rider, see https://www.sonarsource.com/products/sonarlint), which is a free extension that can be used standalone or with SonarQube (Server, Cloud, see: https://www.sonarsource.com/products/sonarqube/ and https://www.sonarsource.com/products/sonarcloud/).