Description
Due to a problem in the Intel® Quartus® Prime Pro Edition software version 19.1 and earlier, you may see this error when the design does not contains a complete Case declaration.
Resolution
To work around this problem, make sure your design contains the default state within the Case declaration.
case (XX)
1: <user defined conditions>;
2: <user defined conditions>;
3: <user defined conditions>;
default: <user defined conditions>;
endcase