I've seen projects like this in the past - either you have skilled people and use a strict CSP from the start, or the footguns of dynamiically crafting objects ultimately leads to a bunch of XSS that (probably) wouldn't have happened with mature frameworks
To be fair, a trait gets you 98% there. It can have default implementations for most functions, you just overwrite the ones you want to change.
You'll still need to declare the underlying struct though, so a bit of extra code
Why not have multiple with different strengths for different users, though? Honggfuzz is also really good.
That being said, most distributions replace afl with afl++ these days.
Yes, LTE makes heavy use of ASN.1, too - the parsers are an interesting target indeed (and some of the fuzzed ones referred to in the paper are such parsers).
Although these days, ASN.1 usually get auto-generated so the attack vector is not as large anymore.
More interesting can be the places where parsed structs then get processed afterward.
I ended up using it over just because it felt easier to use cross platform, and toml seemed like a right choice