[kreetx]

I don't quite get the argument. Isn't this similar to e.g requiring the `z` parameter to be annotated with something that ensures that it is a small number? ("What is the downside of having special syntax for that?")

My undrstanding is that a tail call is a tail call, and the variant with +1 is not that, thus being a candidate to be looked at.

Perhaps also IDEs can help here if it's difficult to spot?

[ajuc]

> Isn't this similar to e.g requiring the `z` parameter to be annotated with something that ensures that it is a small number?

You mean something like "unsigned short int" :) ? Another example would be "const". What's the point - either the variable is const or it isn't. Programmer can just remove the mutation.

> My undrstanding is that a tail call is a tail call, and the variant with +1 is not that, thus being a candidate to be looked at.

Sure, but don't you agree it's an easy mistake to make? Especially when the recursion goes through several different functions. Additionally - you reading the code might not realize it's important for this function to continue to be tail-recursive.

> Perhaps also IDEs can help here if it's difficult to spot?

Or perhaps a compiler can do it?

[kreetx]

I guess we can just agree to disagree here.

Regarding compiler vs IDE, I'd say that since it doesn't change the meaning of the code, just the depth of recursion, then IDE would fit better. Perhaps you could also ask for info on tail-call optimized functions from the compiler giving it a flag, but otherwise I don't think whether something was optimized or not doesn't matter much (depending on what you work on, of course).