Description
Due to a problem in the Intel® Quartus® Prime Standard edition software version 17.1 Update 1 and later, you may get this error message when assigning a value to a structure member inside a function.
Resolution
To work around this problem, assign a value to a structure member within a module scope and outside the function. This problem has been fixed beginning with the Intel® Quartus® Prime Pro edition software version 18.1.