no suitable constructor exists to convert from "int" to "std::expected<int, std::string>" but compiles fine

[akarampetsos]

Environment

• OS and Version: Fedora 38
• VS Code Version: 1.79.2
• C/C++ Extension Version: 1.16.3

Bug Summary and Steps to Reproduce

Bug Summary:

Using std::expected produces errors

Steps to reproduce:

1. Create main.cpp with the following code:

#include <iostream>

#include <string>
#include <expected>

int main() {
    std::expected<int, std::string> t = 1;

    std::cout << t.value() << std::endl;

    return 0;
}

2. Observe an error mark under 1 with the message no suitable constructor exists to convert from "int" to "std::expected<int, std::string>"C/C++(415)

Expected behavior:

No error message. Compiling with g++ main.cpp -std=c++23 works with an output of 1 as expected.

Configuration and Logs

• c_cpp_properties.json

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**"
            ],
            "defines": [],
            "intelliSenseMode": "${default}",
            "cppStandard": "c++23"
        }
    ],
    "version": 4
}

• C/C++: Log Diagnostics

-------- Diagnostics - 6/28/2023, 9:31:57 PM
Version: 1.16.3
Current Configuration:
{
    "name": "Linux",
    "includePath": [
        "/home/alex/dev/test-cpp-23/**"
    ],
    "defines": [],
    "intelliSenseMode": "linux-gcc-x64",
    "cppStandard": "c++23",
    "compilerPathIsExplicit": false,
    "cStandardIsExplicit": true,
    "cppStandardIsExplicit": true,
    "intelliSenseModeIsExplicit": false,
    "macFrameworkPath": [],
    "cStandard": "c23",
    "mergeConfigurations": false,
    "compilerPath": "/usr/bin/gcc",
    "browse": {
        "path": [
            "${workspaceFolder}/**"
        ],
        "limitSymbolsToIncludedHeaders": true
    }
}
cpptools version (native): 1.16.3.0
Translation Unit Mappings:
[ /home/alex/dev/test-cpp-23/main.cpp ]:
    /home/alex/dev/test-cpp-23/main.cpp
Translation Unit Configurations:
[ /home/alex/dev/test-cpp-23/main.cpp ]:
    Process ID: 18931
    Memory Usage: 70 MB
    Compiler Path: /usr/bin/gcc
    Includes:
        /usr/include/c++/13
        /usr/include/c++/13/x86_64-redhat-linux
        /usr/include/c++/13/backward
        /usr/lib/gcc/x86_64-redhat-linux/13/include
        /usr/local/include
        /usr/include
    Standard Version: c++23
    IntelliSense Mode: linux-gcc-x64
    Other Flags:
        --g++
        --gnu_version=130101
Total Memory Usage: 70 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 3684
Number of files parsed: 509

• Logs from the language server logging

LSP: cpptools/textEditorSelectionChange
LSP: cpptools/activeDocumentChange: file:///home/alex/dev/test-cpp-23/main.cpp
LSP: cpptools/textEditorSelectionChange
LSP: cpptools/getCodeActions: file:///home/alex/dev/test-cpp-23/main.cpp (id: 373)
LSP: textDocument/willSaveWaitUntil: file:///home/alex/dev/test-cpp-23/main.cpp (id: 374)
willSaveWaitUntil: 0ms
LSP: textDocument/didSave: file:///home/alex/dev/test-cpp-23/main.cpp
  tag parsing file: /home/alex/dev/test-cpp-23/main.cpp
LSP: cpptools/fileChanged: file:///home/alex/dev/test-cpp-23/main.cpp
idle loop: reparsing the active document
Checking for syntax errors: /home/alex/dev/test-cpp-23/main.cpp
Queueing IntelliSense update for files in translation unit of: /home/alex/dev/test-cpp-23/main.cpp
Error squiggle count: 1
Update IntelliSense time (sec): 0.262
LSP: cpptools/getSemanticTokens: file:///home/alex/dev/test-cpp-23/main.cpp (id: 375)
LSP: cpptools/getFoldingRanges: file:///home/alex/dev/test-cpp-23/main.cpp (id: 376)
LSP: cpptools/getCodeActions: file:///home/alex/dev/test-cpp-23/main.cpp (id: 377)

Additional context

I also found another user who had the same issue and posted a question on stack overflow about it. He suggested that changing the compiler to an older one helped but the issue still persists for me even if I do that. My version of gcc is gcc version 13.1.1 20230614 (Red Hat 13.1.1-4) (GCC)

[Colengms]

This is a duplicate of #11038 , due to underlying unchecked use of __is_convertible. Closing as a duplicate.

[michelleangela]

Fix available in pre-release https://github.com/microsoft/vscode-cpptools/releases/tag/v1.17.0.