Busy editing .groovy file containing trait (when changed to class, same error). @CompileStatic turned on (no effect really by removing it).
Busy with https://github.com/mvniekerk/GrOSHI/ (gradle+groovy project)
Any .groovy file code completion (CTRL+SPACE) results in
"The 'Groovy Code Completions' proposal computer from the 'org.codehaus.groovy.eclipse.codeassist.completion' plug-in did not complete normally." error.