Hi all, Please see attached CMakeLists and cpp file for minimal reproducible example. The throw seems to not always trigger (roughly 20-30% failure rate for me). Compiler: hoc$ clang --version Apple LLVM version 9.0.0 (clang-900.0.39.2) Target: x86_64-apple-darwin17.4.0 Thread model: posix InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin hoc$ system_profiler SPSoftwareDataType | grep Version System Version: macOS 10.13.3 (17D47) Kernel Version: Darwin 17.4.0 -- This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.