syntax check incorrect for some C++ library

[yuanyangwangTJ]

Bug type: Language Service

Describe the bug

• OS and Version: win10
• VS Code Version: latest
• C/C++ Extension Version: v1.8.0
• A clear and concise description of what the bug is, including information about the workspace (i.e. is the workspace a single project or multiple projects, size of the project, etc).
  I use a C++ json library -- nlohmann/json, which is written by modern C++, and I install it by msys2 on win. But when I use it, vscode can't find all member function of this library, just part of it. Actually, my code can be compiled and run. It's terrible to see errors that do not exist in code. May it's my fault for intelliSense configuration? It's worth mentioning that when I open my code by vim editor with a autocomplete plugin YouCompleteMe, there is no error. So where is the problem?

Expected behavior

Vscode with C++ extension can find correct API and member function of library.

Code sample and logs

• Code sample

#include <iostream>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

int main()
{
    json j;
    j.push_back("foo");
    return 0;
}

• Configurations in c_cpp_properties.json

{
    "name": "MSYS2",
    "includePath": [
        "${workspaceFolder}/**"
    ],
    "defines": [],
    "windowsSdkVersion": "10.0.18362.0",
    "compilerPath": "C:/msys64/mingw64/bin/g++.exe",
    "cStandard": "c17",
    "cppStandard": "c++17",
    "intelliSenseMode": "windows-gcc-x64",
    "mergeConfigurations": false
}

• Logs from running C/C++: Log Diagnostics from the VS Code command palette

class "nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t, uint64_t, double, std::allocator, nlohmann::adl_serializer, std::vector<uint8_t, std::allocator<uint8_t>>>" has no member "push_back"

Screenshots

Additional context

[sean-mcmanus]

The bug doesn't repro with 1.7.1 -- a workaround is to change C_Cpp.updateChannel to "Default" instead of "Insiders" to downgrade to 1.7.1.

This is most likely a duplicate of #8475 .

[yuanyangwangTJ]

The bug doesn't repro with 1.7.1 -- a workaround is to change C_Cpp.updateChannel to "Default" instead of "Insiders" to downgrade to 1.7.1.

This is most likely a duplicate of #8475 .

Thanks, v1.7.1 is ok. Hope this extension can support more C++ feature in v1.8 !

[sean-mcmanus]

@yuanyangwangTJ FYI, you can add "-fno-ms-extensions" to compilerArgs with 1.8.0-insiders2 to work around this bug, which was "triggered" by a 1.8.0-insiders bug fix that added -fms-extensions (which is the default for mingw gcc).

[sean-mcmanus]

Fixed with https://github.com/microsoft/vscode-cpptools/releases/tag/1.8.0-insiders3 or 1.8.0 (via using VS Code's "Pre-Release Version" UI or https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools&ssr=false#version-history ).

Unless you're explicitly adding -fms-extensions, in which case that bug fix is still pending (#8353 ).

[sean-mcmanus]

The underlying issue is now fixed with https://github.com/microsoft/vscode-cpptools/releases/tag/1.8.1 , i.e. you can add back -fms-extensions -- however you may still hit other bugs when -fms-extensions are used (#8353).