Cannot see symbols in namespace std with arm-none-eabi.

[ljoseph01]

I am compiling for ARM embedded with arm-none-eabi using coc.nvim with Vim 9.1.

Trying to use std::array gives me the error no template named 'array' in namespace 'std' (ccls 2). I have included the correct header file before the usage and using COC's go to definition takes me to the correct version i.e. the arm-none-eabi file.

My COC setup is as follows:

{
  "inlayHint.enable": false,
  "workspace.rootPatterns": [
      ".cocws"
  ],
  "workspace.workspaceFolderCheckCwd": true,
  "workspace.bottomUpFiletypes": [
      "*.cpp",
      "*.h"
  ],
  "languageserver": {
      "ccls": {
          "command": "ccls",
          "filetypes": ["c", "cpp", "h", "hpp"],
          "rootPatterns": [".cocws", "compile_commands.json", ".vim"],
          "initializationOptions": {
              "cache": {
                  "directory": ".ccls-cache"
              },
              "client": {
                  "snippetSupport": true
              },
              "clang": {
                  "extraArgs": [
                      "--gcc-toolchain=/opt/gcc-arm-none-eabi-10.3-2021.10/",
                      "-isystem/opt/gcc-arm-none-eabi-10.3-2021.10/arm-none-eabi/include",
                      "-isystem/opt/gcc-arm-none-eabi-10.3-2021.10/arm-none-eabi/include/c++/10.3.1"
                  ]
              }
          }
      }
  }
}

As you can see, I have provided the correct compiler path with --gcc-toolchain and -isystem. This is how I got COC to find the correct header file. The header file itself clearly defines the templated array struct. Importantly, this code does compile correctly and I am using the compile commands generated with bear make. The problem is only with the language server.

It is possible that this is an error on my part. Perhaps there is a command line option in the compile commands which is not supported by clang. Any help would be greatly appreciated.

[MJAS1]

Not sure if you are still struggling with this but I had to solve a similar issue. The problem seems to be that bits/c++config.h cannot be found. You need to add one more isystem directory:

"-isystem/opt/gcc-arm-none-eabi-10.3-2021.10/arm-none-eabi/include",
"-isystem/opt/gcc-arm-none-eabi-10.3-2021.10/arm-none-eabi/include/c++/10.3.1"
"-isystem/opt/gcc-arm-none-eabi-10.3-2021.10/arm-none-eabi/include/c++/10.3.1/arm-none-eabi"