This is the write up I was looking for as this is the use case I've had in mind for Racket of late after reading Felleisen's LOP paper.
Would love to know more about your experiences with doing Racket FFI. How hard were the bugs around GC to discover and workaround? What were you building in Racket?
See my responses to a sibling comment for Github bug reports. I had a great experience with them: very fast triage and fixes, plus a lot of help developing a workaround so we could target a range of Racket versions. (Distros still ship some old versions!)
These bugs were found while working on Herbie <http://herbie.uwplse.org/>. We use the FFI to bind to your machine's math libraries so we can properly evaluate how accurate a floating-point expression is on your machine.
Would love to know more about your experiences with doing Racket FFI. How hard were the bugs around GC to discover and workaround? What were you building in Racket?