Emacs, ccls, LSP and C++

[Alexandru-Sergiu Marton <brown121407@posteo.ro>]

Hi,

I have some problems setting up a C++ development environment on Guix
System.

I'm using Emacs with lsp-mode and emacs-ccls. This setup works very well
for C projects, but ccls doesn't seem to like anything related to
C++. Take this simple program for example:

--8<---------------cut here---------------start------------->8---
#include <iostream>

int
main ()
{
  std::cout << "Hello, World!\n";
  return 0;
}
--8<---------------cut here---------------end--------------->8---

Both lsp-mode and eglot tell me that ccls reports: "no member named
'cout' in namespace 'std'".

I have gcc-toolchain installed and I can compile the project just
fine. I tried using bear to generate a compile_commands.json, from this
simple Makefile:

--8<---------------cut here---------------start------------->8---
all:
	g++ main.cpp -o main
--8<---------------cut here---------------end--------------->8---

but ccls still fails to recognize the members of the std
namespace. Irony seems to fail too (same problem), but I haven't tried
playing with it too much, I just tested the default Doom Emacs config.

One more thing: ccls also complains about this, and I don't know what to
make of it:

main.cpp error:20 unknown type name '_GLIBCXX17_DEPRECATED'

Do any of you have experience with setting up a C++ development
environment on Guix System in Emacs? Did you run into similar problems,
and if yes, how did you solve them?

Cheers,
Alexandru-Sergiu Marton