'import os' not used. Wrong Error Message

[Clavismax]

This code only works fine with the import statement:
    
    
    import os
    
    when not (declared(commandLineParams)): # POSIX available?
        echo("Your System ist not POSIX-Compatible.",
            "Your Parameters cannot be determined because the required",
            "Function is not available (commandLineParams).")
    else: # Found POSIX!
        echo("bla bla")
    
    
    Run

But VSCode marks 'os' as import not used... but it is used!

Is this a nim or a VSCode bug? and how can i fix it? (or work around: turn off 
this message!?)