[ufo]

In theory if you call map again with an identical function it should still fall inside the original trace. Tracing JITs effectively inline all function calls that happen inside the trace so if two functions contain the same body they would be indistinguishable.

But there are all sorts of reasons why this might not be happening in that bug report I linked to. It might be due to the definition of the map and reduce functions (luafun adds lots of features to them, so its not just a simple straightforward loop) or it could be due to something about luajit (it is a complex piece of software after all).

The only way to know for sure would be to examine the traces with "luajit -jdump"