Antoine: The scaling is deliberate higher in the recursion limit finder because we just want to ensure it hits the recursion limit (or blows the stack, if the scaling is wrong). In the tests, I cut it finer because I wanted to ensure we were straddling the allowed/disallowed boundary fairly closely in order to properly test the code that accounts for the *existing* recursion depth when initialising the compiler's internal state.

Mark: same answer I gave Antoine earlier. Without the scaling factor, a test fails. If you want to advocate for removing or changing that test instead, track down why it was added and provide a rationale for why it's no longer applicable. However, before you invest too much time in that, note that the trees generated by binary operators of the same precedence in CPython are *not* balanced (IIRC, the LHS is handled as a leaf expression), thus they also suffer from this recursion problem (if you look at the patch I committed, I added an extra test beyond those Andrea provided: a multiplication expression with a ridiculously large number of terms). I agree that path is the only one generated code is likely to hit, though, which is why I added a specific test for it.