Arrays with constant runtime length in Nim, with destructors to support Nim's memory management, as well as a choice between value (Array[T]) or reference (RefArray[T]) semantics. Very basic examples in tests. Potential place for more user-managed collection types in the future.
Depends on the unsafeNew API from Nim to work which seems to have existed for a long time but may be unstable on the new memory management options.
Warning for security critical applications: Not vetted for leaks/UB/memory access issues, ideally would be done with CI.