Noticed T10038, but adding this in case others run into the same problem.
The function getLintCodeFromLinterConfigurationKey($code) in ArcanistCppLinter checks whether a lint message code is valid using:
if (!preg_match('@^[a-z_]+/[a-z_]+$@', $code)) {
...
}However, this is no longer correct, since the there now exist lint codes such as build/c++11 which fail in this regex. We currently use a modified CppLint class that fixes this as follows:
if (!preg_match('@^[a-z_]+/[a-z0-9_+]+$@', $code)) {
...
}