[SOLVED] How do I track down the cause of the Modelsim error(vsim-86) ?

[dpaul]

I am compiling my RTL written in VHDL2008 using Modelsim DE 64 10.5.
THe compiler throws the following error just at simulation start...

# ** Error: (vsim-86) Argument value -8 is not in bounds of subtype NATURAL.
#    Time: 0 ps  Iteration: 1  Instance: /top_tb/path_inst1/path_inst2/......./ff_inst
# ** Error: (vsim-86) Argument value -1 is not in bounds of subtype NATURAL
.
.

I understand that natural is a subtype for integer and has values: 0 to integer'high.

For the sub_module ff_inst, none of my signal declarations are of type natural.

So how to find in my code the source of this error?

 

[FvM]

I presume the reason can be revealed if you show the code.

 

[dpaul]

Ok....got the problem at the end of the day.
So my colleague changed values of two top level design constants and moved them from the top TB to the package file (I was not looking thorouglhy through the committed changes). I could only track it down after reverting to my last working commit.
The ModelSim error confused me and I was focusing at what the heck could be wrong with my sub-module (which was untouched from my colleague's commit) which was not showing any problem till yesterday night and before I pulled in the new changes.