wasm-core-2 Spec 5.5.12. Element Section decoding funcref/func types do not match elem.wast or 3.0 Spec

[kelnishi]

When decoding an element section according to 5.5.12. Element Section, the segment type is incorrectly listed as func (ref func) for case 4. This is covered under elem.wast and should be (ref null func) like in the 3.0 draft spec. Posted versions of the core 2.0 spec also have a similar discrepancy where both decode case 0 and case 4 are listed as funcref (ref null func). According to elem.wast testing, the types of case 0 and case 4 differ and should be (ref func) and (ref null func), respectively.

[rossberg]

The GC proposal has been merged into the main repo's Wasm 3.0 branch, so the gc repo generally isn't updated with upstream changes anymore. It is correct in the Wasm 3.0 draft.

[rossberg]

As for the 2.0 spec, that is correct as is, since non-nullable references do not exist in 2.0 yet. The change in 3.0 (and according tests) is a backwards-compatible refinement.

[kelnishi]

Thank you for the explanation. I've been building against the gc spec and testing with the gc test suite. Maybe I missed it, but I did not see any information on where to find the appropriate spec for a given test suite. I had just assumed that the test suite from gc would have matched the spec that was also it linked in the gc repo's readme.

[rossberg]

It was a spec bug in the funcref proposal that got fixed in that repo. Not sure why the fix didn't make it downstream to the GC repo in the first place, might have been some screw-up when resolving merge conflicts. To avoid further confusion, I added it now.