Prototype of @AnnotationMixing Feature for ProjectLombok

after-ejcSLASHAnnotationMixinSimple.java

@interface Base{
	String a() default "A";
	int b();
	int c();
}

@interface Custom1{
	String a() default "AA";
	int b();
	int c();
}

AnnotationMixin.java

package lombok.experimental;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.ANNOTATION_TYPE)
@Retention(RetentionPolicy.SOURCE)
public @interface AnnotationMixin {
	
	AnyAnnotation[] copyMethodsFrom() default {};
	
	/**
	  * Placeholder annotation to enable the placement of annotations on the generated code.
	  * @deprecated Don't use this annotation, ever - Read the documentation.
	  */
	@Deprecated
	@Retention(RetentionPolicy.SOURCE)
	@Target({})
	@interface AnyAnnotation {}
}

beforeSLASHAnnotationMixinSimple.java

import lombok.experimental.AnnotationMixin;

@interface Base{
	String a() default "A";
	int b();
	int c();
}

@AnnotationMixin(copyMethodsFrom=@__({@Base}))
public @interface Custom1{
	String a() default "AA";
}

HandleAnnotationMixin.java

package lombok.javac.handlers;

import static lombok.javac.handlers.JavacHandlerUtil.*;
import lombok.core.AnnotationValues;
import lombok.experimental.AnnotationMixin;
import lombok.javac.JavacASTVisitor;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;

import org.mangosdk.spi.ProviderFor;

import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.util.List;

@ProviderFor(JavacAnnotationHandler.class)
public class HandleAnnotationMixin extends JavacAnnotationHandler<AnnotationMixin> {
	
	@Override public void handle(AnnotationValues<AnnotationMixin> annotation, JCAnnotation ast, JavacNode annotationNode) {
		annotationNode.getAst().traverse(new JavacASTVisitor.Printer(false));
		
		deleteAnnotationIfNeccessary(annotationNode, AnnotationMixin.class);
		deleteImportFromCompilationUnit(annotationNode, "lombok.experimental.AnnotationMixin");
		
		List<JCAnnotation> copyMethodsFrom = unboxAndRemoveAnnotationParameter(ast, "copyMethodsFrom", "@AnnotationMixin(", annotationNode);
		for (JCAnnotation anno : copyMethodsFrom) {
			
			// FYI annotationNode.getImportList() -> defs seems to contain the Type
			// definition of the @Base annotation that I'm looking for, but I can't find a way to access it... :-( 
			
			// Question: How can I access the method definitions of the annotations 
			// found in copyMethodsFrom?
			
			// TODO inject method declarations of the annotations found in
			// copyMethodsFrom if such method declarations do not exist yet.
		}
	}
}