alt Hacker NewsIt’s precisely not the semantics of the program that will crash the program, but the behavior of the language implementation. It’s similar to when a program in a GC language fails with OOM because the language implementation uses a no-op collector. That’s usually not part of programming language semantics.
Replies
If you wrote a correct binary search algorithm and you observed that, under one language implementation, the time complexity scaled linearly with the size of the input instead of logarithmically, you would think the semantics of the program were changed.
If you used an in-place sort algorithm and observed memory requirements that scale super-linearly with the size of the input, you would think the semantics of the program were changed.
In languages with such tail call guarantees, tail recursion _is_ a loop. It semantically encodes constant space complexity.
The specification allows implementations to have limits on maximum call stack depth and all sorts of other things. It's absolutely semantically meaningful in C to allocate a new stack frame.
Tail call elimination often is part of the language semantics though, for the reason others in this thread have described. E.g. Scheme specifies when a conformant implementation is required to eliminate tail calls: https://conservatory.scheme.org/schemers/Documents/Standards...