BeefLang will report leaks as they occur, not when the program shuts down. There's a tracing "GC" in debug mode for detecting unreachable memory in realtime. It's also used for reliably detecting use-after-free since memory is held when there are references and released when the last reference goes away -- again, a debug-only feature.

This is totally possible with custom allocators in Odin too. You'll be surprised by how much custom allocators can do, but so many people know little about them.

Am I understanding correctly that in Odin feature could even be provided by a third party library implementing such a custom collector? If so, that's seriously cool.