My suggestion for these issues of correctness and my suggestion for issues of performance/static compilation are basically the same – there should be a Julia “core” (in both Base and in other libraries) that is not at all generic and is essentially C code written in Julia. This code won’t need to cover an infinite set of types (so rigorous testing is feasible) and this code could be trivially statically compiled if the compiler got better because exactly which methods exist and which are called could be fully determined statically.
In general, I fear the ever-growing push for more generic code makes both performance and correctness worse with no end in sight. And I don’t think most people actually need that much generic code.