Others have responded, but without much depth. Common Lisp on SBCL (maybe the proprietary compilers are similar/better, I haven't worked with them) has a remark

Others have responded, but without much depth. Common Lisp on SBCL (maybe the proprietary compilers are similar/better, I haven't worked with them) has a remarkably good type inference system. You need to declare, which is optional, but of course you'd need to declare all your types anyway in Rust or C++. The result is extremely good- for a highly dynamic language. Real number crunchy code actually gets very close to bare metal performance with type declarations, though if you're doing generic function calls it'll choke up fast. So to get fast, the compiler knows the types because you tell it. For safe, you don't need to do anything- CL is garbage collected. It's easy to have fast or safe in any language- doing both requires type declarations and a good optimizing compiler. That being said, none of that matters for this discussion. Nyxt uses Webkit under the hood because CL, even with SBCL pulling off genuine miracles, is not really intended to go toe to toe with C. I think of CL as occupying around the same niche as Java, which it's usually only a bit slower than.