[snicker7]

> So if your unoptimized Julia program relies upon traditional "dynamic" features like

Dynamic dispatch is slow in any language, including C/C++ (provided that the compiler can't devirtualize the method). This is why such things are never done in an inner loop.

In C++, its harder to "accidentally" use dynamic dispatch because you have to explicitly annotate a function as being virtual. In Julia, which is much more concise, type stability or instability is implicit. But it can be inspected statically via @code_warntype. Good IDE plug-ins can make it easier.