panel_type cannot be both const char* and PanelType you have to rename one of these two variables.

Since "panel_type" is much longer than "pt" some long lines like this need reformatting. Clang format can take care of that for you: https://wiki.blender.org/wiki/Tools/ClangFormat

People sometimes forget to run clang format before committing, so it can happen that areas you haven't touched get reformatted as well. If that happens, make sure to not include those changes in your patch - they will be taken care of by someone in a cleanup commit. ;)

In the new developers' guide it is written that the clang format is already available in the c/c++ tools in vscode, and installing the separate extension is the old procedure and not needed now, which is the method specified in the link you have suggested. I am already using clang format and format on save in vscode, and the formatting seemed alright to me. If there is anything wrong with my setup, please guide me on how to fix it.

Well, applying your patch and running make format in the console changes a bunch of stuff: P2879 (Not only your stuff, btw...)
Maybe try running make format through the console yourself. If it changes anything, there probably is an issue with the setup.

Since I don't use vscode a lot, I unfortunately can't help you much, except suggest to recheck, if you setup everything according to the description you mentioned.

I wasn't aware that the setup for clang format changed. So that's good to know, thanks!