title: groovy BUG! exception in phase 'canonicalization' in source unit (Groovy v 2.4.7 versus 2.4.8)
body: <p>I tried updating from Groovy v 2.4.7 to 2.4.8 as this version is supposed to fix a problem with keeping the transient effective for not serializing from subclasses. After updating to 2.4.8 I get:</p>
  
  <blockquote>
    <p>Caused by: BUG! exception in phase 'canonicalization' in source unit 'C:\Dev\Perseus\ContentManagement\core\src\main\groovy\com\agenabio\content\Content.groovy' unexpected NullpointerException
        at org.gradle.api.internal.tasks.compile.ApiGroovyCompiler.execute(ApiGroovyCompiler.java:174)</p>
  </blockquote>
  
  <p>Is there a solution for this?</p>