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I don’t understand the desire to staple a GC into Rust. If you want this, you might just…want a different language? Which is fine and good! Putting a GC on Rus

I don’t understand the desire to staple a GC into Rust. If you want this, you might just…want a different language? Which is fine and good! Putting a GC on Rust feels like putting 4WD tyres on a Ferrari sports car and towing a caravan with it. You could (maybe) but it feels like using the wrong tool for the job.

dajonker 1y ago
If I understand the article correctly it's for those cases where you want memory safety (i.e. not using "unsafe") but where the borrow checker is really hard to work with such as a doubly linked list, where nodes can point to each other. For the rest you'd still use non-GC rust.
- FridgeSeal 1y ago
  I just foresee it become irrevocably viral, as it becomes the “meh, easier” option, and then suddenly half your crates depend on it, and then you’re losing one of the major advantages of the language.
- zozbot234 1y ago
  A doubly linked list is not the optimal case for GC. It can be implemented with some unsafe code, and there are approaches that implement it safely with GhostCell (or similar facilities, e.g. QCell) plus some zero-overhead (mostly) "compile time reference counting" to cope with the invariants involved in having multiple references simultaneously "own" the data. See e.g. https://github.com/matthieu-m/ghost-collections https://github.com/matthieu-m/ghost-collections for details. Where GC becomes necessary is the case where even static analysis cannot really mitigate the issue of having multiple, possibly cyclical references to the same data. This is actually quite common in some problem domains, but it's not quite as simple as linked lists.
lmm 1y ago
Adding a GC to Rust might honestly be easier than getting the OCaml ecosystem to adopt something that works as well as cargo. It's tragic, but that's the world we live in.
- debugnik 1y ago
  Of all the things I'd change about OCaml, dune is very much down the list. It's flat out better than cargo in that it's an actual build system with build rules driven by file dependencies, not simply a glorified frontend for a compiler. Not great, but better. Now, upstreaming OxCaml's unboxed types and stack allocations? That might actually take longer than adding a GC to Rust.

dajonker 1y ago

If I understand the article correctly it's for those cases where you want memory safety (i.e. not using "unsafe") but where the borrow checker is really hard to work with such as a doubly linked list, where nodes can point to each other. For the rest you'd still use non-GC rust.

FridgeSeal 1y ago
I just foresee it become irrevocably viral, as it becomes the “meh, easier” option, and then suddenly half your crates depend on it, and then you’re losing one of the major advantages of the language.
zozbot234 1y ago
A doubly linked list is not the optimal case for GC. It can be implemented with some unsafe code, and there are approaches that implement it safely with GhostCell (or similar facilities, e.g. QCell) plus some zero-overhead (mostly) "compile time reference counting" to cope with the invariants involved in having multiple references simultaneously "own" the data. See e.g. https://github.com/matthieu-m/ghost-collections https://github.com/matthieu-m/ghost-collections for details. Where GC becomes necessary is the case where even static analysis cannot really mitigate the issue of having multiple, possibly cyclical references to the same data. This is actually quite common in some problem domains, but it's not quite as simple as linked lists.

lmm 1y ago

Adding a GC to Rust might honestly be easier than getting the OCaml ecosystem to adopt something that works as well as cargo. It's tragic, but that's the world we live in.

debugnik 1y ago
Of all the things I'd change about OCaml, dune is very much down the list. It's flat out better than cargo in that it's an actual build system with build rules driven by file dependencies, not simply a glorified frontend for a compiler. Not great, but better. Now, upstreaming OxCaml's unboxed types and stack allocations? That might actually take longer than adding a GC to Rust.