message: Verify first body is not empty before testing last character.
  Avoids sigabrt where body is empty.
diff: @@ -266,7 +266,7 @@ OpMethodBody &OpMethodBody::operator<<(int content) {
  void OpMethodBody::writeTo(raw_ostream &os) const {
  os << body;
  - if (body.back() != '\n')
  + if (body.empty() || body.back() != '\n')
  os << "\n";
  }
  