Really depends on your IDE. As an example, Visual Studio ships Microsoft's CPP compiler (MSVC [0]), but uses a completely different compiler frontend (namely EDG [1]) for IntelliSense.

In a way, it does use a compiler to resolve the candidate functions, but it doesn't go through all the compilation stages. And it's not even the same compiler as when you hit compile :)

[0]: https://en.wikipedia.org/wiki/Microsoft_Visual_C%2B%2B

[1]: https://www.edg.com/