4 ms·

The last time I looked (which has been a while, I admit), that meant that you had a very hard time using any of the standard library types with an arena or what

• tialaramex 4y ago
  If you're willing to write Nightly Rust, you can use the allocator_api feature to have the types which allocate take an allocator parameter so e.g. Vec::with_capacity_in(10, arena_allocator) ... obviously user-defined types don't know these allocators exist and so may not provide a way to pick which allocator is used, whereas in Zig this is "always" how it worked. For stable Rust, until/ unless allocator_api is stabilized, you will need to replace the global allocator for your code with one that has the desired behaviour. That applies to everything using an allocator, but on the other hand you lose considerable flexibility.