Scala IDE (i.e., Eclipse) has a feature where there is a special icon in the left gutter on every line where an implicit argument is used invisibly. You can mouse over the icon and it will provide more detailed information. This feature is called "Implicit highlighting" in the Scala IDE manual.
Does IntelliJ have a similar feature? I miss this feature of Scala IDE.
P.S. I have figured out how to get IntelliJ to highlight implicit conversions, but that's not the same thing.