Apex unused methods and variables to find dead code

[sumitshingavi]

Is your feature request related to a problem? Please describe.
Complex customer orgs. often have lots of Apex and need bulk code cleanup tool where we can find unused methods and variables in apex and generate a report to hand it off to the partner for cleanup. Currently, few IDEs do provide this functionality but very expensive license.

Describe the solution you'd like

1. If you open an Apex class if the developer can see highlighted unused methods and variables will help.
2. If we can also detect copy-pasted blocks then it would be the icing on the cake.

Describe alternatives you've considered

1. CodeScan.io provides this analysis but it is expensive for customers
2. PMD Java ruleset does have these rules but transforming them for Apex is not easy.

Additional context
Add any other context or screenshots about the feature request here.