Incorrect calculation of long double

Environment

• OS and Version: Debian 12
• VS Code Version: 1.96.2
• C/C++ Extension Version: 1.23.6

Bug Summary and Steps to Reproduce

Bug Summary:
The extension produces wrong value for calculations related to long double.

A. int cast to long double

Steps to reproduce:

1. Write code like this:

const long double a = 1;

2. Move the mouse pointer to a
3. See error: the popup window shows -0.0L

Expected behavior:
The popup window shows 1.0L or so.

B. double cast to long double

Similar.

C. long double * long double

Steps to reproduce:

1. Write code like this:

const long double a = 1.0L * 2.0L;

2. Move the mouse pointer to a
3. See error: the popup window shows 0.0L

Expected behavior:
The popup window shows 2.0L or so.

Configuration and Logs

{
    "configurations": [
        {
            "name": "Linux",
            "cppStandard": "c++23",
            "compilerPath": "${HOME}/usr/bin/g++",
            "includePath": [
                "${workspaceFolder}/**"
            ],
            "defines": [],
            "intelliSenseMode": "linux-gcc-x64"
        }
    ],
    "version": 4
}


-------- Diagnostics - 3/21/2025, 5:22:04 PM
Version: 1.23.6
Current Configuration:
{
    "name": "Linux",
    "cppStandard": "c++23",
    "compilerPath": "/home/iw17/usr/bin/g++",
    "includePath": [
        "/home/iw17/Documents/cpp/**"
    ],
    "defines": [],
    "intelliSenseMode": "linux-gcc-x64",
    "compilerPathIsExplicit": true,
    "cStandardIsExplicit": true,
    "cppStandardIsExplicit": true,
    "intelliSenseModeIsExplicit": true,
    "compilerPathInCppPropertiesJson": "${HOME}/usr/bin/g++",
    "cStandard": "c23",
    "mergeConfigurations": false,
    "browse": {
        "path": [
            "/home/iw17/Documents/cpp/**",
            "${workspaceFolder}"
        ]
    }
}
Modified Settings:
{
    "C_Cpp.suggestSnippets": false,
    "C_Cpp.errorSquiggles": "enabled",
    "C_Cpp.default.cStandard": "c23",
    "C_Cpp.default.cppStandard": "c++23",
    "C_Cpp.default.browse.limitSymbolsToIncludedHeaders": false,
    "C_Cpp.vcFormat.indent.braces": true,
    "C_Cpp.vcFormat.indent.caseContentsWhenBlock": true,
    "C_Cpp.vcFormat.newLine.beforeCatch": false,
    "C_Cpp.vcFormat.newLine.beforeElse": false,
    "C_Cpp.vcFormat.space.withinInitializerListBraces": false,
    "C_Cpp.vcFormat.space.groupSquareBrackets": false,
    "C_Cpp.vcFormat.space.beforeInheritanceColon": false,
    "C_Cpp.vcFormat.space.beforeConstructorColon": false,
    "C_Cpp.vcFormat.space.pointerReferenceAlignment": "ignore",
    "C_Cpp.autoAddFileAssociations": false,
    "C_Cpp.addNodeAddonIncludePaths": true
}
Additional Tracked Settings:
{
    "editorTabSize": 4,
    "editorInsertSpaces": true,
    "editorAutoClosingBrackets": "languageDefined",
    "filesEncoding": "utf8",
    "filesAssociations": {},
    "filesExclude": {
        "**/.git": true,
        "**/.svn": true,
        "**/.hg": true,
        "**/CVS": true,
        "**/.DS_Store": true,
        "**/Thumbs.db": true,
        "**/.classpath": true,
        "**/.factorypath": true,
        "**/.project": true,
        "**/.settings": true
    },
    "filesAutoSaveAfterDelay": false,
    "editorInlayHintsEnabled": true,
    "editorParameterHintsEnabled": true,
    "searchExclude": {
        "**/node_modules": true,
        "**/bower_components": true,
        "**/*.code-search": true
    },
    "workbenchSettingsEditor": "json"
}
cpptools version (native): 1.23.6.0
Current database path: /home/iw17/.cache/vscode-cpptools/ebd2e673b3dd5949bad93a40e0f18162/.browse.VC.db
Translation Unit Mappings:
[ /home/iw17/Documents/cpp/nongli-test/clean.cpp - source TU]:
[ /home/iw17/Documents/cpp/test/test.cpp - source TU]:
    /usr/include/x86_64-linux-gnu/bits/stdint-uintn.h
Translation Unit Configurations:
[ /home/iw17/Documents/cpp/nongli-test/clean.cpp ]
    Process ID: 61200
    Memory Usage: 51 MB
    Compiler Path: /home/iw17/usr/bin/g++
    Includes:
    System Includes:
        /home/iw17/usr/include/c++/14.2.0
        /home/iw17/usr/include/c++/14.2.0/x86_64-pc-linux-gnu
        /home/iw17/usr/include/c++/14.2.0/backward
        /home/iw17/usr/lib/gcc/x86_64-pc-linux-gnu/14.2.0/include
        /usr/local/include
        /home/iw17/usr/include
        /home/iw17/usr/lib/gcc/x86_64-pc-linux-gnu/14.2.0/include-fixed
        /usr/include/x86_64-linux-gnu
        /usr/include
    Standard Version: c++23
    IntelliSense Mode: linux-gcc-x64
    Other Flags:
        --g++
        --gnu_version=140200
[ /home/iw17/Documents/cpp/test/test.cpp ]
    Process ID: 64755
    Memory Usage: 19 MB
    Compiler Path: /home/iw17/usr/bin/g++
    Includes:
    System Includes:
        /home/iw17/usr/include/c++/14.2.0
        /home/iw17/usr/include/c++/14.2.0/x86_64-pc-linux-gnu
        /home/iw17/usr/include/c++/14.2.0/backward
        /home/iw17/usr/lib/gcc/x86_64-pc-linux-gnu/14.2.0/include
        /usr/local/include
        /home/iw17/usr/include
        /home/iw17/usr/lib/gcc/x86_64-pc-linux-gnu/14.2.0/include-fixed
        /usr/include/x86_64-linux-gnu
        /usr/include
    Standard Version: c++23
    IntelliSense Mode: linux-gcc-x64
    Other Flags:
        --g++
        --gnu_version=140200
Total Memory Usage: 70 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 6405
Number of files parsed: 1593

Other Extensions

The issue persists no matter whether all the other extensions are enabled or disabled.

Additional context

No response

Riproduci i valori al passaggio del mouse in clean.cpp e test.cpp usando la configurazione indicata Debian, GCC 14.2.0, C++23 e linux-gcc-x64. Parti dal percorso di valutazione del passaggio del mouse di IntelliSense e confronta la gestione delle espressioni int, double e long double; il lavoro è completato quando le dichiarazioni segnalate e la moltiplicazione mostrano i valori previsti senza influire sugli altri risultati al passaggio del mouse.