Have you changed the implementation in the meantime? I'm asking that because according to the error message, the error should be found in line 15 inside the method Application::alt_text_bhvr_cls.recursive_check(). From the above screenshots the method ends with line 3.
Nevertheless, in the last screenshot in line 20 you assign a value to an object. This is an error. The object exists already. You can change the content of the object by accessing and modifying its variables/properties. The object itself can't be replaced by other object. This explains the error message. The operand on the left of the assignment operator can#T receive a value.
If you want to store an object, which later is replaced by other object, use variable:
1. Select and delete alt_prop_clss.
2. Add a new variable member.
3. Name the variable member alt_prop_clss.
4. Configure the type of the variable to be Application::alt_prop_cls.
Please note, as long as the variable is not explicitly initialized, it will contain null. That means 'null-object'. You can initialize the variable with new Application::alt_prop_cls then it will refer a valid object . Later when you assign a new object to the variable, the old object will be freed and new object will be stored in the variable.
I hope it helps you further.
bnest regards
Paul Banach