Merge pull request #1470 from bytecodealliance/pch/wiggle_error_model

Wiggle: changes to traits used for error conversion and reporting

crates/wiggle/generate/src/funcs.rs

@@ -62,9 +62,10 @@ pub fn define_func(
                 _ => unreachable!("err should always be passed by value"),
             };
             let err_typename = names.type_ref(&tref, anon_lifetime());
+            let err_method = names.guest_error_conversion_method(&tref);
             quote! {
                 let e = wiggle::GuestError::InFunc { funcname: #funcname, location: #location, err: Box::new(e.into()) };
-                let err: #err_typename = wiggle::GuestErrorType::from_error(e, ctx);
+                let err: #err_typename = GuestErrorConversion::#err_method(ctx, e); // XXX replace with conversion method on trait!
                 return #abi_ret::from(err);
             }
         } else {