alt Hacker News> Native interop with JS objects on the JS GC heap isn't supported as well.
Isn't that what the i31 type is for, that extra bit is a tag for...something, native GC'd object perhaps? Not so clear on that myself as Java's object model (minus synchronized) slots in perfectly so my Java 1.0 -> wasm compiler doesn't need it but that's my limited understanding of what it's for.
I'm not sure what they mean by "native" here but (ref extern) is for host references, JS or otherwise. The i31 type is for "immediate" values, things that can fit in 31 bits and thus don't need to be allocated on the heap.