Good questions. I'm afraid the documentation is seriously out of date about the GC: It used to implement a variant of "trial deletion" so that "never scans the whole heap" used to refer to the fact that it doesn't use traditional mark&sweep, but only scans the subgraph(s) leading to the cycles. Of course you can always create a "subgraph" that spans the whole heap, so even for trial deletion it is a dubious claim.
Since version 0.14 (iirc) however, Nim uses a traditional mark&sweep backup GC to collect cycles. Reasons: Trial deletion in practice is much slower.
For all versions of the GC is stack is scanned conservatively as precise stack scanning is simply too expensive when C is your main target.
Since version 0.14 (iirc) however, Nim uses a traditional mark&sweep backup GC to collect cycles. Reasons: Trial deletion in practice is much slower.
For all versions of the GC is stack is scanned conservatively as precise stack scanning is simply too expensive when C is your main target.