Thanks, we confirm that VS 16.10 is missing one of the classes used by language services (such as Clang IntelliSense) to query information from Visual Studio using the backward-compatible COM interfaces. We are working on this and will release a hotfix in the next couple of hours.
Update: we have added a workaround to the issue to the following build: VisualGDB-220.127.116.1119.msi. We will also release hotfixes for VisualGDB 5.5 and VisualKernel 3.1 soon.
Update #2: we have also released VisualGDB 5.5R5 and VisualKernel 3.1R9 that include a fix to this issue. You can get them via the regular download pages if you do not want to install the beta.