News such as this one do not build confidence though: https://internals.rust-lang.org/t/type-inference-breakage-in...
Though I suspect it’s fair to say the entire settlement is built of glass houses here :-)
https://news.ycombinator.com/item?id=43798312
I suppose if one wants absolutely no surprises, they will need to lock the entire toolchain as well, regardless of the language…