Using @CompileStatic in Grails grails.util.PluginBuildSettings class causes this kind of compilation errors:
[Static type checking] - Cannot return value of type [Lorg.codehaus.groovy.grails.io.support.Resource; on method returning type org.codehaus.groovy.grails.io.support.Resource
I've tried to isolate the problem, but I didn't succeed. I pushed a branch that has the compile error in it.
git clone -b cs-bug-arrays https:cd grails-core
./gradlew install -PskipTests -x signArchives -x docs -x javadoc -x gdoc -x groovydoc -x javadocJar -x sourcesJar