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by throw10920 1014 days ago
> 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.
2 comments
mtsr 1014 days ago
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.

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lmm 1014 days ago
You can use unsafe if you really want to "turn the borrow-checker off", no?
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throw10920 1014 days ago
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.
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lmm 1014 days ago
If you're saying you want GC/Arc then that's more than just "turning off the borrow checker".
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throw10920 1014 days ago
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.
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lmm 1012 days ago
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.
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throw10920 1012 days ago
You're right, I have been overly aggressive. I apologize.

> 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.

There's use-cases for wanting your language to be productive outside of prototyping, such as scripting (which I explicitly mentioned earlier in this thread[1] - omission here was not intentional), and quickly setting up tools (such as long-running web services) that don't need to be fast, but should not leak memory.

"Use Rust, but turn the borrow checker off" is inadequate.

[1] https://news.ycombinator.com/item?id=37441120

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