Reflection-based schema not loading types

Avro reflection is unable to generate a schema for the following definition:

 
public class Definition {
    public Map<String, Type>
}

public enum Type {
  A,
  B,
  C
}

// Test code
Schema schema = ReflectData.get().getSchema(Definition.class)

Fails with:
Undefined name: "FieldType"
org.apache.avro.SchemaParseException: Undefined name: "Type"