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

Reproduce the hover values in clean.cpp and test.cpp using the reported Debian, GCC 14.2.0, C++23, and linux-gcc-x64 configuration. Start from the IntelliSense hover evaluation path and compare handling of int, double, and long double expressions; done means the reported declarations and multiplication show their expected values without affecting other hover results.