Ruby uses C underneath, so if there is an implementation issue of how C is used to implement a feature in Ruby, it could still lead to issues.

But most of the ruby language is tested at trunk by the big companies like shopify, github etc to patch any issues.

I largely agree with this though: > even “safe” code (in any language) will have to call traditional C or C++ code or be called by traditional code that does not offer specific safety guarantees.