[JonChesterfield]

Maximum stack usage can be calculated in the presence of recursion. Tail calls can be handled as branches instead of nested call frames, but also non-tail calls are tolerable if you have (or can infer) some measure to determine maximum call stack depth.

It's a pain, and the type system rejecting any recursion is certainly simpler, but that's not a strict requirement.

[_0w8t]

Inferring the number of loop integrations or recursion levels is in practice impossible when the number depends on the user input.

For a system language I would like to see that when the compiler cannot infer the bound on the stack size or when that static bound exceeds some static limit, a function call is treated as fallible.