Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 18.0 or earlier, you may see this error message if the 'std.env' package is imported in any VHDL source file. The error occurs when the VHDL 2008 standard is used to synthesize the project.
To work around this problem, remove the 'std.env' package for synthesis and include it only for simulation purposes.
This problem is fixed beginning with version 18.1 of the Intel® Quartus® Prime Pro Edition Software.