Visual Studio “Go to definition” disabled or gray out

Question

Visual Studio\'s Go To Definition is disabled and F12 doesn\'t work. Other commands like Alt-F12 may continue working.

Answer 1

I've just had this happen with a CMake-based C++ project in Visual Studio 2019. Everything was fine yesterday, then when I opened it up today all the Go To Definition/Declaration etc options were greyed out everywhere in every file in the project, even for things defined within the same file (and the syntax highlighting didn't look right either). It did work if I opened one of the .cpp files separately on its own (without loading the Project/Solution).

I tried various things including the answers here and telling it to generate the CMake cache again, but what finally fixed it was actually deleting the CMake cache. The Delete Cache option didn't seem to work (all the files were still there on disk, and there was some sort of failure message in the Output window) so I just deleted the entire "out" directory from the project directory (well, moved it somewhere outside of the project, just in case). Loaded up Visual Studio again, it rebuilt the cache again automatically and IntelliSense immediately started working again! I just had to wait 5 minutes for it to compile everything again when I wanted to run the project.

Maybe it wasn't necessary to remove the entire "out" directory, but when I clicked "Open in Explorer" under the "CMake Cache" menu it opened the actual build directory (which was the only thing in the "out" directory anyway) so I assumed the entire thing was related to the cache and was getting too fed up with it to try to narrow it down further. It's probably only certain files within that directory really.