enum used as a key does not work

In my YANG model, I'm using an enum leaf as key. That passes POJO generation, but fails the Java compilation. For instance, if I use the following perfectly valid model, it fails mvn build (when I use Beryllium-SR1 yangtools).

module model1 {
namespace "model1";
prefix "model1";
revision 2016-04-21 { }

grouping A {
leaf B {
type enumeration {
enum X {}
enum Y {}
}
}
}

container C {
list D

}
}

mvn compilation generates the following error.

[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] model/src/main/yang-gen-code/org/opendaylight/yang/gen/v1/model1/rev160421/c/DBuilder.java:[40,32] incompatible types: java.lang.Enum cannot be converted to org.opendaylight.yang.gen.v1.model1.rev160421.A.B
[ERROR] model/src/main/yang-gen-code/org/opendaylight/yang/gen/v1/model1/rev160421/c/DBuilder.java:[150,36] incompatible types: java.lang.Enum cannot be converted to org.opendaylight.yang.gen.v1.model1.rev160421.A.B
[INFO] 2 errors
[INFO] -------------------------------------------------------------

When I look deeper into the code generated, I see that DKey generates with the field of type Enum instead of type B (which is what DBuilder.java is expecting). The only way to get pass this issue is to define the enumeration separately as a typedef. If I do that, things work fine.