Null Range (empty range)

In VHDL, you can use ranges with to and downto. But, if you use the wrong direction, you get an empty range, which is usually not what you want.

signal foo: std_logic_vector(7 downto 0)  -- range of 8;
signal foo: std_logic_vector(7 to 0)      -- null range;

We have a lint check that warns about this, even if you use constants or some simple arithmetic.

Project specific setting of these rules

These rules can be disabled for your project, or its severity can be modified in the project linting settings.

Manual configuration in ${project location}/.settings/com.sigasi.hdt.vhdl.linting.prefs: