message: Throw error on totally unknown section id
diff: @@ -46,9 +46,21 @@ Module parse(bytes_view input)
  case SectionId::code:
  std::tie(module.codesec, it) = parser<std::vector<Code>>{}(it);
  break;
  - default:
  + case SectionId::custom:
  + case SectionId::import:
  + case SectionId::function:
  + case SectionId::table:
  + case SectionId::global:
  + case SectionId::export_:
  + case SectionId::start:
  + case SectionId::element:
  + case SectionId::data:
  + // These sections are ignored for now.
  it += size;
  break;
  + default:
  + throw parser_error{
  + "unknown section encountered " + std::to_string(static_cast<int>(id))};
  }
  if (it != expected_end_pos)
  