Surprised that I'm the only person so far mentioning F#, where units of measure have been built in to the language since 1.0: https://learn.microsoft.com/en-us/dotnet/fsharp/language-ref...

I wrote a longer comment in reply to nraynaud elsewhere describing how I found it useful for certain things at a past job. It's hardly a killer feature, but it's very nice to have the compiler (partially) verify the semantic correctness of certain floating-point computations. It's not just physics - finance has "units" as well, and the compiler can complain if you gave a function an array of dollars/week when it wanted dollars/month.

If you don't mind writing some (admittedly tedious) overhead it can save a lot of headaches.