I chuckled at this passage: "flint is written in the D language, making it the first D codebase open-sourced by Facebook. In fact, our initial version of flint was written in C++; the D rewrite started as an experiment. From the measurements and anecdotes we gathered, the translation turned out to be a win on all fronts: the D version of the linter turned out smaller, dramatically faster to build, significantly faster to run, and easier to contribute to."

Seems like the argument is stronger to rewrite the code being linted, than to use the linter itself ;-)