[hajile]

The two reasons for tail calls are loops and CPS. Nobody is championing the idea that we need traces for each loop iteration. I would somewhat understand the CPS argument except that the event loop already destroys a huge amount of meaningful stack traces anyway (while not identical, it is somewhat similar). I don't see anyone insisting on stack traces there either.

Why do we need explicit tail calls with stack traces?

[nostrademons]

That's an argument in favor of explicit tail call syntax. If there are only two main use-cases (loops and CPS), then why not annotate those two use-cases and leave everything else untouched?

The problem with implicit tail call syntax is that suddenly stack traces will be elided from debugging info when you really just wanted a normal function call that happened to be in tail position. These are really hard-to-track-down bugs, since the stack frame that is elided is precisely the one that made the tail call.

[bzbarsky]

Browsers are adding stack traces across the event loop, precisely because people _do_ commonly want them.