Can Local Transformer be added to Trait?

[杨波]

Hello,

Is it possible to add a local transformer to the Trait like this?

```groovy
@Retention(RetentionPolicy.RUNTIME)
@GroovyASTTransformationClass(["swagger.grails4.compiler.ApiDocTransformer"])
@interface ApiDoc {
  String value() default ""
}

@CompileStatic
@GroovyASTTransformation(phase = CompilePhase.SEMANTIC_ANALYSIS)
class ApiDocTransformer extends AbstractASTTransformation {

    @Override
    void visit(ASTNode[] nodes, SourceUnit source) {
        // processing Class node it should be an Interface because trait is 
transformed to Interface and some helper classes
        // But The trasformer will not be triggered for Trait
    }
}

@ApiDoc("My Trait")
trait MyTrait {
}
```

I have tried like this but the transformer can not be invoked for Trait.

If I add the @ApiDoc annotation to implementing class the transformer can be 
invoked, 
but how can I transform trait methods such as adding an annotation to getter 
method?

Thanks.



Best Regards,

Bob Yang