we have some classes using @Delegate on generic classes:
Sometime compilation fails with compiler errors like
BUG! exception in phase 'class generation' in source unit '/Users/andre/Development/Projects/Adternity/grf/grails-app/jobs/com/grf/reports/ScheduledReportExecutionJob.groovy' Type is null. Most probably you let a transform reuse existing ClassNodes with generics information, that is now used in a wrong context. (Use --stacktrace to see the full trace)
I assume this has to do with DelegateASTTransformation#nonGeneric handling of generic types, which is setting the generic type to null, but it's hard to reproduce the error in a determined way.