[thedigitalengel]

(Disclaimer: I know nothing about Ruby, but I know some things about JIT compilers)

Another way to handle this is to assume that Fixnum#+ hasn't changed when compiling a method that is using it (maybe add a check at method entry); but when it does get redefined you "deoptimize" the methods that you compiled while holding that assumption.

[vidarh]

That's what this referred to:

> or you need to record every call-site with inlined code and be prepared to overwrite it with fixups if the implementation changes.