When I read that, I thought "What a huge TCB versus what's typical." Additionally, there exist verified strategies for parsing that might be applicable to Scala

When I read that, I thought "What a huge TCB versus what's typical." Additionally, there exist verified strategies for parsing that might be applicable to Scala. Depends on if their formalisms can handle the language's grammar or whatever. Additionally, if they write untrusted parts in ML, they can supplant it with stuff like property-based testing or CakeML compiler.