Description
Due to a limitation in the Quartus® II software, you cannot have functions and units with the same name. Min is defined as a unit of time in the package STANDARD along with fs, ps, ns, us, ms, sec and hr. Therefore, if you have a function called min in your VHDL code, this definition causes a conflict.
Resolution
To work around this limitation, either rename your function to something other than min or reference the function explicitly. For example:
work.min_max_package.min