message: Amend assert message
  Summary: As title.
diff: @@ -674,7 +674,8 @@ void IRTypeChecker::run() {
  IRInstruction* insn = mie.insn;
  try {
  auto it = type_envs.find(insn);
  - always_assert(it != type_envs.end());
  + always_assert_log(
  + it != type_envs.end(), "%s in:\n%s", SHOW(mie), SHOW(code));
  check_instruction(insn, &it->second);
  } catch (const TypeCheckingException& e) {
  m_good = false;
  