When unmarshal XML, xSream pass incorrect "definedIn" in Mapper.shouldSerializeMember

When unmarshaling an XML the XStream verify if the field must be deserialized using Mapper.shouldSerializeMember(java.lang.Class definedIn, java.lang.String fieldName)

The verification done by com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.doUnmarshal(final Object result, final HierarchicalStreamReader reader, final UnmarshallingContext context)
The problem is that the class passed in shouldSerializeMember as "definedIn" parameter is incorrect.

Example:

class A{String a;}
class B extends A{String b;}

when unmarshaling the instance of the class B and verifying field "String a" , xStream pass into shouldSerializeMember the class B as "definedIn" instead of class A.

—
The problem is in the class com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter at line 302.
I suggest to you to change this line:

"|| !mapper.shouldSerializeMember(classDefiningField != null ? classDefiningField : result.getClass(), fieldName)) {"

by

"|| !mapper.shouldSerializeMember(field.getDeclaringClass(), fieldName)) {"

Failing unit test: