不支持新增成员变量？

请问后续版本修复，还是有限制原因？
public void addAddedFields(DexBackedField field) {
addedFields.add(field);
throw new RuntimeException("can,t add new Field:" +
field.getName() + "(" + field.getType() + "), " + "in class :" +
field.getDefiningClass());
}

public void addModifiedFields(DexBackedField field) {
modifiedFields.add(field);
throw new RuntimeException("can,t modified Field:" +
field.getName() + "(" + field.getType() + "), " + "in class :" +
field.getDefiningClass());
}

Start with the addAddedFields and addModifiedFields entry points shown in the issue and trace where addedFields and modifiedFields are handled. Determine whether adding or modifying member fields is intentionally unsupported; done should be a documented decision or a complete, tested implementation of the requested behavior.

Written by the indexing model from the issue text.