Panic when calling `ExportedFunction` with WASI function name about wazero

[mathetake]

sorry for the delay - yeah first of all this cryptic panic is indeed a bug, and ExportedFunction should return nil or either panic saying this is forbidden. I will fix it. Having said that, host functions are not designed to be called directly like this vs normal Wasm modules in wazero - host module’s functions are invoked with the caller modules context, meaning it should have the access to the memory of the caller (e.g. wasip1 “host module” should be able to read/write the memory of the caller to perform system call). Which has the totally different semantics of the normal wasm modules obviously. (please note host module is not defined in the spec, but this is how generally host functions are implemented).
That’s the reason why api.Module is not returned by wasi_snapshot_preview1.MustInstantiate or similar functions but instead they just return api.Closer. That is intentional api decision.

copypasta my comment from slack