ID:13670 VHDL error at <location>: invalid formal parameter

CAUSE: In a VHDL Design File (.vhd) at the specified location, you used a formal parameter. However, the formal parameter is invalid, for example, the implied type of the formal parameter may not be the same as the type of the return value in a Subprogram Declaration. Refer to Section 6 of the IEEE Std 1076-1993 IEEE Standard VHDL Language Reference Manual for more information on the restrictions for formal parameters.

ACTION: Remove the formal parameter, or make sure the formal parameter is legal.