Intellij IDEA doesn't grey out some unused methods

Question

In intellij IDEA, if a method is unused, the method is shown in a gray color. But in some cases, IDEA doesn't grey out the method, but when I check the references of those methods using alt + F7, IDEA says that the method is unused.

Is this a IDEA bug or is there any reason why IDEA wouldn't grey out these specific methods? If it is a bug, is there some workaround to make IDEA identify that method is unused?

Answer 1

I used to have it working like charm, but one time, I by mistake clicked on alt+Enter on an unused method, and chose to suppress the inspection on unused code. Ever since then, I stopped getting the grayed out methods and code, so since there is a way to get it undone, there sure must be a way to get it back working.

After 5 minutes of searching, I found a solution:

Settings --> Editor --> Inspections --> Java --> Declaration Redundancy --> Unused Declaration

Make sure you check "Unused Declaration"

And I just checked by creating a new useless method, working like a charm.

Answer 2

Most likely it's not a bug, it's a limitation for performance reasons. Methods likely to take a long time when searching for usages are skipped.

A workaround is to run Unused Declaration inspection explicitly in all your project via Analyze | Inspect Code or Analyze | Run Inspection by Name. That'll take some time. You can also set up TeamCity server to do it for you automatically every night.