message: check for anonymous operations
diff: @@ -112,10 +112,13 @@ function getConstructor(extAttrs: webidl2.ExtendedAttributes[], parent: string)
  }
  function convertOperation(operation: webidl2.OperationMemberType): Browser.Method {
  + if (!operation.name || !operation.idlType) {
  + throw new Error("Unexpected anonymous operation");
  + }
  return {
  - name: operation.name!,
  + name: operation.name,
  signature: [{
  - ...convertIdlType(operation.idlType!),
  + ...convertIdlType(operation.idlType),
  param: operation.arguments.map(convertArgument)
  }],
  getter: operation.getter ? 1 : undefined,
  