Space Before the Physical Unit

If you type a numeric literal with a physical unit, there should be a space between the number and the unit.

    T := 25ns;  -- ILLEGAL, but accepted by ModelSim
    T := 25 ns; -- OK; according to VHDL language standard

Mentor Graphics’ ModelSim and QuestaSim accept the former (illegal) version. As a result, some VHDL designers got used to writing the incorrect version, producing code that is not portable to other simulators. Sigasi Visual HDL accepts the ModelSim-style physical literals but warns about this (rule 47).

Rule Configuration

This rule can be disabled for your project, or its severity and parameters can be modified in the project linting settings. Alternatively, it can be manually configured with the following template:

47/severity/${path}={error|warning|info|ignore}