> It has shown that GC vs manual memory management has a third option.
Objective-C has only existed a few decades now.
Objective-C has only existed a few decades now.
Rust's ownership + borrowing instead of being somewhere on the axis of performance vs correctness trade-off, has traded off generality/flexibility instead (infamous for being unfit for doubly-linked lists). Unlike ARC, it works without a run-time, and on bare allocations and stack objects too. Unlike C++, it has zero-cost slices/substrings without a risk of dangling pointers.
AFAIK Objective-C has lots of reference counting.
The phrase "garbage collection" has also come to be somewhat associated with tracing's specific characteristics (IMO). Manual memory management is performant and deterministic, but unsafe. Tracing garbage collection is performant and safe, but nondeterministic. Reference counting is deterministic and safe, but not as performant. If you throw Rust into the mix as a fourth option I suppose you could add a "flexible" characteristic.
Not as performant in a theoretical model with unlimited memory that all costs the same to access. ie it’s not actually faster in practice when peak memory matters and swap exists.
Rust avoids copies and occasionally proves single ownership instead of having RCs. This seems to me to be overoptimization and a waste of programmer time. Copies are fine and you don’t need to prove them away.