compile error with covariant bridge method added for already existing method

Open groovyConsole, enter:

class Foo {
@Delegate Date d = new Date();
}

Press Ctrl+Enter. Error displayed:

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed, Script14: -1: Repetitive method name/signature for method 'int compareTo(java.lang.Object)' in class 'Foo'.
@ line -1, column -1.Script14: -1: Repetitive method name/signature for method 'int compareTo(java.lang.Object)' in class 'Foo'.
@ line -1, column -1.
2 errors

Note: changing Date to other classes such as Map works fine, seems to be something specific about Date.