Coroutines: error when non-copyable/non-movable returned from `await_resume`

Bắt đầu bằng cách tái hiện báo cáo trong main.cpp với C++20 và cấu hình Windows MSVC IntelliSense được mô tả. Theo dõi chẩn đoán tại biểu thức co_await khi await_resume trả về foo không thể sao chép; được xem là hoàn tất khi IntelliSense không báo dấu gạch chân lượn sóng lỗi nào trong khi các trình biên dịch được liệt kê vẫn tiếp tục chấp nhận mã.

Environment

• OS and Version: Windows 11 25H2
• VS Code Version: 1.110.0
• C/C++ Extension Version: 1.30.5
• If using SSH remote, specify OS of remote machine: None

When returning a non-copyable and non-movable value from await_resume of an awaiter, intellisense reports this error at the co_await point (using MSVC as compiler): function "foo::foo(foo &&)" cannot be referenced -- it is a deleted function.

Nevertheless, MSVC, GCC and Clang accept the code and the program behaves as expected.

Bug Summary and Steps to Reproduce

Bug Summary:

Steps to reproduce: Paste the following snippet:

#include <coroutine>
#include <exception>

struct fire_and_forget final
{
    struct promise_type;
};

struct fire_and_forget::promise_type final
{
    static constexpr fire_and_forget get_return_object() noexcept { return {}; }
    static constexpr std::suspend_never initial_suspend() noexcept { return {}; }
    static constexpr std::suspend_never final_suspend() noexcept { return {}; }

    static constexpr void return_void() noexcept {}
    inline static void unhandled_exception() noexcept { std::terminate(); }
};


struct foo final
{
    foo() = default;

    foo(foo const &) = delete;
    foo &operator=(foo const &) = delete;

    foo(foo &&) = delete;
    foo &operator=(foo &&) = delete;
};

struct my_awaiter final
{
    bool await_ready() { return false; }
    void await_suspend(auto) {}
    foo await_resume() { return foo{}; }
};

fire_and_forget test()
{
    auto x = co_await my_awaiter{}; // error here
}

Expected behavior: No error squiggles

Configuration and Logs

// c_cpp_properties.json

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**",
                "${workspaceFolder}/src"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE"
            ],
            "windowsSdkVersion": "10.0.26100.0",
            "intelliSenseMode": "windows-msvc-x64"
        }
    ],
    "version": 4
}

C/C++: Log Diagnostics

-------- Diagnostics - 3/5/2026, 12:04:00 PM
Version: 1.30.5
Current Configuration:
{
    "name": "Win32",
    "includePath": [
        "<User>/thing/cpp/entt_scheduler_demo/**",
        "<User>/thing/cpp/entt_scheduler_demo/src"
    ],
    "defines": [
        "_DEBUG",
        "UNICODE",
        "_UNICODE"
    ],
    "windowsSdkVersion": "10.0.26100.0",
    "intelliSenseMode": "windows-msvc-x64",
    "compilerPathIsExplicit": true,
    "cStandardIsExplicit": true,
    "cppStandardIsExplicit": true,
    "intelliSenseModeIsExplicit": true,
    "recursiveIncludesReduceIsExplicit": false,
    "recursiveIncludesPriorityIsExplicit": false,
    "recursiveIncludesOrderIsExplicit": false,
    "cStandard": "c17",
    "cppStandard": "c++20",
    "mergeConfigurations": false,
    "recursiveIncludes": {},
    "compilerPath": "${env:CXX}",
    "browse": {
        "limitSymbolsToIncludedHeaders": true
    }
}
Modified Settings:
{
    "C_Cpp.inlayHints.autoDeclarationTypes.enabled": true,
    "C_Cpp.inlayHints.parameterNames.enabled": true,
    "C_Cpp.autocompleteAddParentheses": true,
    "C_Cpp.errorSquiggles": "enabled",
    "C_Cpp.default.compilerPath": "${env:CXX}",
    "C_Cpp.default.cStandard": "c17",
    "C_Cpp.default.cppStandard": "c++20",
    "C_Cpp.commentContinuationPatterns": [
        "/*"
    ],
    "C_Cpp.codeAnalysis.clangTidy.enabled": true,
    "C_Cpp.codeAnalysis.clangTidy.args": [
        "-isystem=CMakeLists.txt",
        "*"
    ],
    "C_Cpp.codeAnalysis.clangTidy.checks.disabled": [
        "cppcoreguidelines-avoid-magic-numbers",
        "cppcoreguidelines-avoid-c-arrays",
        "fuchsia-default-arguments-calls",
        "fuchsia-default-arguments-declarations",
        "fuchsia-overloaded-operator",
        "hicpp-avoid-c-arrays",
        "llvm-include-order",
        "llvm-header-guard",
        "llvmlibc-*",
        "modernize-avoid-c-arrays",
        "readability-magic-numbers"
    ],
    "C_Cpp.experimentalFeatures": "enabled"
}
Additional Tracked Settings:
{
    "editorTabSize": 4,
    "editorInsertSpaces": true,
    "editorAutoClosingBrackets": "languageDefined",
    "filesEncoding": "utf8",
    "filesAssociations": {},
    "filesExclude": {
        "**/.git": true,
        "**/.svn": true,
        "**/.hg": true,
        "**/.DS_Store": true,
        "**/Thumbs.db": true
    },
    "filesAutoSaveAfterDelay": false,
    "editorInlayHintsEnabled": true,
    "editorParameterHintsEnabled": true,
    "searchExclude": {
        "**/node_modules": true,
        "**/bower_components": true,
        "**/*.code-search": true
    },
    "workbenchSettingsEditor": "ui"
}
cpptools version (native): 1.30.5.0
Current database path: <User>\APPDATA\LOCAL\MICROSOFT\VSCODE-CPPTOOLS\8867B49488CF20A004321616C2AF107D\.BROWSE.VC.DB
Translation Unit Mappings:
[ <User>\thing\cpp\entt_scheduler_demo\main.cpp - source TU]:
Translation Unit Configurations:
[ <User>\thing\cpp\entt_scheduler_demo\main.cpp ]
    Process ID: 25624
    Memory Usage: 85 MB
    Compiler Path: C:\Program Files\Microsoft Visual Studio\18\Community\VC\Tools\MSVC\14.50.35717\bin\Hostx64\x64\cl.exe
    Include paths:
        include: <User>\thing\cpp\entt_scheduler_demo\src
        system include: C:\Program Files\Microsoft Visual Studio\18\Community\VC\Tools\MSVC\14.50.35717\include
        system include: C:\Program Files\Microsoft Visual Studio\18\Community\VC\Tools\MSVC\14.50.35717\atlmfc\include
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\um
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\ucrt
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\shared
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\winrt
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\cppwinrt
    Defines:
        _DEBUG
        UNICODE
        _UNICODE
    Standard Version: ms_c++20
    IntelliSense Mode: windows-msvc-x64
Total Memory Usage: 85 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 5892

Other Extensions

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Additional context

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