ValType toString surprising behavior

[andreaTP]

Noticed when printing function signatures, ValType.ExternRef prints as RefNull[-17] which is a little confusing.

[andreaTP]

After digging a bit, I'm not sure about the Parser, the problem is that I cannot match on Externref , for example here.
I'm about to be out for a week and don't have time to dig deeper now, I leave my wip here.

Maybe @hypercubestart have a clue on top of his head? This is the kind of wasm file I'm targeting.