The Problem
Every now and then I get this annoying problem in GGTS (Grails/Groovy Tool Suite – Version 3.6.2.RELEASE at the time of this writing), where the IDE just complains about how it can’t resolve a class. The weird thing is that the file that the IDE is complaining about is in the same package as the class that I’m trying to use. It built before, and the source hadn’t changed – so clearly this should not be happening.
The Fix
Hitting the Clean button on the Eclipse side (Project -> Clean) seems to make the errors go away.
This apparently has been a problem since June 2010 (forum post reference here), so I’m surprised that it is still an issue in the current version.