... because objects cannot be zero-sized in C++. It's also a much better default, as it gives us some kind of idea of what magnitude of space we are talking about for types that haven't specialized JS::ubi::Node::size yet.

The old default was zero, but one is a better default in a couple ways: (1) there are no zero-sized things in C++ so one is closer to the truth, and (2) it gives us an idea of what magnitude of space is consumed by node specializations which don't have a JS::ubi::Node::size override yet.

Casting a wide try push net, because I have a sneaking suspicion that some test somewhere depends on the old default (boo). https://treeherder.mozilla.org/#/jobs?repo=try&revision=8ba65929231d

Comment on attachment 8653477 [details] [diff] [review] Make JS::ubi::Node::size return 1 by default Review of attachment 8653477 [details] [diff] [review]: ----------------------------------------------------------------- Fine with me, though I see how it could play havoc with tests.

Semi-surprisingly, the try push looks fine!