Empty Values Returned when Fragment is Used Inside Another Fragment to Query a Service Object

[ThisaruGuruge]

Description:
Consider the following scenario:

import ballerina/graphql;

service /graphql on new graphql:Listener(9000) {
    resource function get teacher() returns Teacher {
        return new (737, "Walter White", "Chemistry");
    }
}

distinct service class Teacher {
    private int id;
    private string name;
    private string subject;

    public isolated function init(int id, string name, string subject) {
        self.id = id;
        self.name = name;
        self.subject = subject;
    }

    isolated resource function get id() returns int {
        return self.id;
    }

    isolated resource function get name() returns string {
        return self.name;
    }

    isolated resource function get subject() returns string {
        return self.subject;
    }
}

When querying this using the following document:

query {
    ... QueryFragment
}

fragment QueryFragment on Query {
     teacher {
         ...TeacherFragment
     }
}

fragment TeacherFragment on Teacher {
    ...NameFragment
}

fragment NameFragment on Teacher {
    name
}

The result is the following:

{
    "data": {
        "teacher": {}
    }
}

Expected result:

{
    "data": {
        "teacher": {
            "name": "Walter White"
        }
    }
}