[waf]

Visual Studio does semantic highlighting for at least C# (they call it enhanced highlighting). Static classes, parameters, internal structure of regex strings, etc. Basically anything returned by the Roslyn Classification API.

I personally like it, but I think other people feel that syntax highlighting plus semantic highlighting leads to rainbow soup.

[maxmouchet]

Semshi [1] does it for Python and I find it very useful for identifying errors such as missing imports, misspelled variables, etc.

[1] https://github.com/numirias/semshi

[deadbunny]

Oooh, this is very nice. Thanks for sharing!