[buildartefact]

>There's no option to "turn the borrow checker off" - which means that when you're in prototyping mode, you pay this huge productivity penalty for no benefit

That’s not really true. The standard workaround for this is just to .clone() or Rc<RefCell<>> to unblock yourself, then come back later and fix it.

It is true that this needs to be done with some care otherwise you can end up infecting your whole codebase with the “workaround”. That comes with experience.

[throw10920]

> It is true that this needs to be done with some care otherwise you can end up infecting your whole codebase with the “workaround”

It's a "workaround" precisely because the language does not support it. My statement is correct - you cannot turn the borrow-checker off, and you pay a significant productivity penalty for no benefit. "Rc" can't detect cycles. ".clone()" doesn't work for complex data structures.

[mtsr]

You can’t turn off undefined behavior in C++ either. Lifetimes exist whether the language acknowledges them or not.

Except if you go to a GC language, but then you’re prototyping other types of stuff than you’d probably pick Rust for.

[lmm]

You can use unsafe if you really want to "turn the borrow-checker off", no?

[throw10920]

No, because that doesn't give you automatic memory management, which is the point. When I'm prototyping, there's zero reason for me to care about lifetimes - I just want to allocate an object and let the runtime handle it. When you mark everything in your codebase unsafe (a laborious and unnecessary process that then has to be laboriously undone), you still have to ask the Rust runtime for dynamic memory manually, and then track the lifetimes in your head.

[lmm]

If you're saying you want GC/Arc then that's more than just "turning off the borrow checker".

[throw10920]

Pedantry. Later on in my comment I literally say "manage memory for you" - it should be pretty clear that my intent was to talk about a hypothetical language that allowed you to change between use of a borrow checker and managed memory, even if I didn't use the correct wording ("turn off the borrow checker") in that particular very small section of it.

[lmm]

Bit much to complain about pedantry with how prickly your tone has been in this whole thread. If you only want this functionality for rapid iteration/prototyping, which was what you originally said, then leaking memory in those circumstances is not such a problem.