> Even better would be to just automatically insert a tail call - like every other language that has supported tail calls for decades - provided the callee has the same signature as the caller.
I've used Scala for many years and concluded this was a mistake. It makes it too easy to accidentally rely on an optimisation and then break your code much later with a seemingly innocuous change. Better to make it explicit.
Sure, but if you're relying on the TCO, you kind of have to actually state that, regardless? (At least if you want to avoid accidental regressions.)
I don't see any way around having to state your intent (as a programmer) for this. It's just a semantic difference in behavior unless your Abstract Machine allows for just ignoring the possibility of stack overflow entirely.
