Chapter 6

1. The Solidity linters do report some security issues at the Solidity level. They also help in finding common security issues. 
2. No, having 100% contract coverage does not mean that testing is done efficiently. It only suggests that all the possible branches have been covered by the test cases. However, there could be more test scenarios that are not covered by the test cases; they must be included in the test suite by the developers.
3. When you are trying to debug and find out the internal function traces of a specific function, function traces should be used. This will help you understand the transaction flow in the case of complex contract structures.
4. It is good practice to use the Solidity linters for projects. The linters find the common issues that would improve your code quality, and sometimes also report common security issues.

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