IntelliJ show errors in scala source files but the project compiles successfully

Question

I'm working with project in intellij IDEA IDE based in maven. I can perform all maven goals but IntelliJ is showing a lot of errors in the source code like bellow:

Everything worked fine a few hours ago. I don't understand why the IDE continue showing errors. When I rebuild or compile the entire project (CTRL + F9) or a single scala class I always receive a success message like that:

I already had configured scala plugin before, so I don't know what is happen.

thanks for your help

Answer 1

Sometimes the IntelliJ cache gets corrupted. You can fix this by the following:

File > "Invalidate Caches / Restart"

After choosing "Invalidate and Restart" when prompted, IntelliJ will restart and rebuild its cache.

Answer 2

If IDEA has lost track of obviously correct types such as Database or DateTime it probably means the configuration of the project is wrong or corrupted. Most commonly it does not have the required 3rd part dependencies such as Joda Time.

If you're not already doing so, define your project solely in SBT and use the sbt-idea plug-in to produce your IDEA project definition. Then whenever you change the project dependencies, re-run gen-idea to regenerate your IDEA project files. No muss, no fuss.