[jkrejcha]

> No mainstream implementation does that for memory unsafety due to the performance overhead

It depends on what is considered memory safety here (especially when some of them are arguably unforced errors in the standards), but many implementations do in fact have options for this ("no delete null pointer checks" for example is an example of one such option, for example, which is used extensively by the Linux kernel for example).

The performance impact tends to be much more negligible outside of, sometimes contrived, benchmarks, especially when compared to algorithmic efficiencies or the like.