VS2022 Version 17.6.0 Preview 3.0 - Standard Library Modules warnings (std.ixx)

So, this morning I’m back from my Easter break and working on some code for a client and the first thing I do is kick off my CI build and things start failing. It seems that my “cunning plan” to have my CI build use the preview version of Visual Studio 2022 whilst the client uses earlier versions has paid off again…

We build with all warnings enabled and treat warnings as errors. Of course, I suppress quite a few warnings that are false positives but in general this works well, especially since we build like this with VS2017, 2019, 2022, 2022 Preview and then various flavours of GCC and CLang on Windows and MacOs. Enabling all warnings and having to think about which ones I suppress is useful and has found some issues in the past.

Today we have VS2022 Version 17.6.0 Preview 3.0 generating warnings for MSVC\14.36.32522\include\ppltaskscheduler.h MSVC\14.36.32522\include\pplwin.h, neither of which I was aware of before as we don’t explicitly use them… Also, lots of random noise during the compile from std.ixx …

Rather annoyingly the warnings that are popping up are all things that my suppressions normally deal with, but they all come out of the std.ixx compilation.

It seems to be related to support for Standard Library Modules which appear to be enabled by default in this preview and which I will now disable explicitly here..

Luckily, I have a project file updater that I can adjust so that this is less painful when updating all of the projects involved…