remove dedicated MacroExpansion variable (reuse Definition)
added empty MACRO test

I have also moved the expansion out of the location checking branch. I think it's to find out if a macro actually has a definition which isn't always the case especially for special macros like __FILE__.

resolve review comment

fix patch context

fix line end to LF

It looks like my inline comment wasn't submitted (didn't click the submit button on the bottom). Here's my old comment.

use a rebased patch

Sorry I'm a little occupied lately.

• add context to patch
• use a fixed size buffer for expansion text

To elaborate on known situation where expansion isn't available:

1. expansion doesn't work on site of #define
2. expansion doesn't work for _Pragma(...) and alike
3. expansion doesn't work with builtin macro
4. expansion doesn't work for macros as arguments of function-like macro

I have a similar change recently presented in https://github.com/clangd/clangd/issues/1181 that makes all conditional preprocessor lines active. Please refer to the change if that's helpful :)

Yes, please do so. I'm using the web interface since the arc tool isn't very friendly to Windows user :(

squashed commits.
updated comments.

added unit test
moved redundant visit