Most of these uses are very rare, but the tail is incredibly long for Python, and the problem is that you can't even compile a "likely normal" and a "here be dragons" versions, and switch only when needed - you need to constantly verify. The same is not true, AFAIK, with Common Lisp - being a lisp1 and having a stronger lexical scope than python does.
Shedskin is a Python to C++ compiler that mostly requires the commonly-honoured constrained that a variable is only assigned a single type throughout its lifetime. (And that you don't modify classes after creation, and that you don't need integers longer than machine precision, and ....); While many programs seem to satisfy these requirements on superficial inspection, it turns out that almost all programs violate them in some way (directly or through a library).
The probability that Shedskin will manage to compile a program that was not written with Shedskin in mind is almost zero.
Nuitka was started with the idea that, unlike shedskin, it will start by compiling the bytecode to an interpreter-equivalent execution (which it does, quite well), to get a minor speed up - and then gradually compile "provably simple enough" things to fast C++; a decade or so later, that's not working out as well as hoped, AFAIK because everything depends on something that violates simplicity.
